Mapping Mountains – Summit Relocations – 30-99m Twmpau

30-99m Twmpau – Summit Relocations

The 30-99m Twmpau (thirty welsh metre prominences and upward) are the Welsh hills at or above 30m and below 100m in height that have 30m minimum drop.  Accompanying the main list are two sub lists entitled the 30-99m Sub-Twmpau with the criteria being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, and the Double Sub-Twmpau with the criteria being all Welsh hills at or above 20m and below 30m in height with 20m or more and below 30m of drop.

The list is authored by Myrddyn Phillips and the posts that have appeared on Mapping Mountains detailing the Summit Relocations to the main P30 list and the sub lists appear below presented chronologically in receding order.

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Yr Allt (SN 552 024) - 35th summit relocation

Hill Reclassifications post for Yr Allt

Significant Name Changes post for Yr Allt

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Yr Allt (SN 552 024)

The criteria for the list that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

30-99m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Yr Allt and this was drived from the Tithe map, and it is adjoined to the Mynydd Sylen group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with minor roads to its north and west, and the A4138 road to its south, and has the town of Llanelli towards the west south-west.

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with 26m of drop, based on the 97m summit spot height positioned at SN 55266 02448 and the 71m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis gives the highest ground on this hill as 97.4m positioned at SN 55275 02452 and SN 55274 02450.  However, this is a part of a raised field boundary and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Yr Allt (SN 552 024)

The height produced by LIDAR analysis to the natural summit of this hill is 96.8m and this is positioned at SN 55279 02446, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the height produced by LIDAR analysis to the natural summit of this hill is 96.8m and is positioned at SN 55279 02446, this position is relatively close to where the spot height appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, and is approximately 6 metres south-eastward from where the high point of the raised field boundary is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Yr Allt 

OS 1:50,000 map:  159

Summit Height:  96.8m (LIDAR) 

Summit Grid Reference (New Position):  SN 55279 02446 (LIDAR)               

Bwlch Height:  71.05m (LIDAR) 

Bwlch Grid Reference:  SN 54918 02542 (LIDAR) 

Drop:  25.75m (LIDAR) 

 

Myrddyn Phillips (August 2024)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Coed Abergwynant (SH 677 178) - 34th summit relocation

Significant Name Changes post for Coed Abergwynant

 

There has been confirmation of a Summit Relocation to a hill that is listed in the 30-99m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Coed Abergwynant (SH 677 178)

The criteria for the list that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

30-99m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Coed Abergwynant, and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and it is positioned with the A493 road to its south-east, and has the town of Dolgellau towards the east.

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a non-interpolated summit height of c 90m, with the prioritised summit positioned at SH 681 177, with an accompanying note stating; Three points of same height – other at SH 679 178 and SH 676 177, a reference to the three uppermost 90m ring contours that appear on the contemporary Ordnance Survey 1:25,000 Explorer map.

When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 51m of drop, based on an estimated c 97m summit height positioned at SH 67728 17847 and a 46m bwlch height, based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis gives the highest ground on this hill as 97.1m positioned at SH 67725 17843, and when compared to the original prioritised summit position this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the height produced by LIDAR analysis to the summit of this hill is 97.1m and is positioned at SH 67725 17843, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 390 metres westward and placed in a different map contour compared to where the original prioritised listed summit is positioned. 

 

The full details for the hill are:

Group:  Cadair Idris 

Name:  Coed Abergwynant 

OS 1:50,000 map:  124

Summit Height:  97.1m (LIDAR) 

Summit Grid Reference (New Position):  SH 67725 17843 (LIDAR)               

Bwlch Height:  46.7m (LIDAR) 

Bwlch Grid Reference:  SH 68287 17879 (LIDAR) 

Drop:  50.4m (LIDAR) 

 

Myrddyn Phillips (July 2024)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

The Head (SM 731 046) - 33rd summit relocation

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau, Y Trechol – The Dominant Hills of Wales and Y Pellennig – The Remotest Hills of Wales, with the summit height and its location, the drop, dominance, remoteness and status of the hill prompted by detail produced by Joe Nuttall in his surface analysis programme (JNSA). 

The criteria for the three listings that this summit relocation applies to are: 

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

30-99m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

Y Pellennig – The Remotest Hills of Wales - Welsh hills whose summit is at least 2.5km from the nearest paved public road and the hill has 15m minimum drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is available as a downloadable e-booklet and print-booklet version on Mapping Mountains Publications with the up-to-date master list available to download on the Mapping Mountains site in Google Doc format.

Y Pellennig - The Remotest Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is The Head, and it is adjoined to the Garn Fawr group of hills which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned on the island of Skokholm which is positioned to the south-west of the Pembrokeshire coast.

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a 55m summit height positioned at SM 730 047, with an accompanying note stating; Height from 1:10000 map, details from David Purchase.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 56m summit height and drop, based on interpolation of its largest 55m uppermost contour positioned at SM 72969 04698.  The summit position was subsequently and slightly amended to SM 72970 04701 from detail that appeared on the Hill Bagging website. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until Joe Nuttall developed his surface analysis programme that the details of this hill could be analysed via the OS Terrain product.  The height produced by the surface analysis programme is 55.0m and this is positioned at SM 73112 04672, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the height produced by the surface analysis programme developed by Joe Nuttall is 55.0m and is positioned at SM 73112 04672, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is positioned to a different 55m contour and approximately 42 metres eastward from where the previously listed summit is positioned. 

 

The full details for the hill are: 

Group:  Garn Fawr

Name:  The Head

OS 1:50,000 map:  157

Summit Height:  55.0m (JNSA)

Summit Grid Reference (New Position):  SM 73112 04672 (JNSA)

Bwlch Height:  N/A (island)

Bwlch Grid Reference:  N/A (island)

Drop:  55.0m (JNSA)

Dominance:  100.00% (island)

Remoteness:  5.21km (JNSA)

 

Myrddyn Phillips (May 2024)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Cefn y Coed (SH 667 172) - 32nd summit relocation

Significant Height Revisions post for Cefn y Coed

Significant Name Changes post for Cefn y Coed

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Cefn y Coed (SH 667 172)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

30-99m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is now listed by is Cefn y Coed and this was derived from the Tithe map, and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and it is positioned with the A493 road to its south-east, and has the town of Dolgellau towards the east.

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a non-interpolated summit height of c 90m positioned at SH 666 172, with an accompanying note stating; Two points of same height, a reference to the two uppermost 90m ring contours that appear on the contemporary Ordnance Survey 1:25,000 Explorer map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 64m of drop, based on an estimated c 91m summit height positioned at SH 66668 17206 and an estimated c 27m bwlch height, based on interpolation of 10m contouring between 20m – 30m, with these values giving this hill 70.33% dominance.

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis gives the highest ground on this hill as 89.0m positioned at SH 66751 17241, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the height produced by LIDAR analysis to the highest ground on this hill is 89.0m and is positioned at SH 66751 17241, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 83 metres north-eastward and placed in a different map contour compared to where the previously listed summit is positioned. 

 

The full details for the hill are:

Group:  Cadair Idris 

Name:  Cefn y Coed 

OS 1:50,000 map:  124

Summit Height:  89.0m (LIDAR) 

Summit Grid Reference (New Position):  SH 66751 17241 (LIDAR)               

Bwlch Height:  26.7m (LIDAR) 

Bwlch Grid Reference:  SH 67045 17182 (LIDAR) 

Drop:  62.3m (LIDAR) 

Dominance:  69.98% (LIDAR) 

 

Myrddyn Phillips (May 2024)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Cae Pen y Cefn (SH 532 377) - 31st summit relocation

Hill Reclassifications post for Cae Pen y Cefn

Significant Name Changes post for Cae Pen y Cefn

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Cae Pen y Cefn (SH 532 377)

The criteria for the list that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

30-99m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Cae Pen y Cefn and this was derived from the Tithe map, and it is adjoined to the Moel Hebog group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with a minor road to its north and south, and the A497 road farther to its north, and has the town of Porthmadog towards the east north-east.

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 20m of drop, based on the 58m summit spot height that appears on the contemporary Ordnance Survey 1:25000 Explorer map and which is positioned at SH 53282 37746, and an estimated c 38m bwlch height, based on interpolation of 5m contouring between 35m – 40m. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis gives the highest ground on this hill as 58.5m positioned at SH 53278 37755.  However, this is a part of a raised field boundary and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Cae Pen y Cefn (SH 532 377)

The height produced by LIDAR analysis to the highest remaining natural ground on this hill is 57.8m and this is positioned at SH 53267 37729, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the height produced by LIDAR analysis to the highest remaining natural ground on this hill is 57.8m and is positioned at SH 53267 37729, this position is relatively close to where the spot height appears on the contemporary Ordnance Survey 1:25,000 Explorer map, and is approximately 26 metres south-westward from where the high point of the raised field boundary is positioned. 

 

The full details for the hill are: 

Group:  Moel Hebog 

Name:  Cae Pen y Cefn 

OS 1:50,000 map:  124

Summit Height:  57.8m (LIDAR) 

Summit Grid Reference (New Position):  SH 53267 37729 (LIDAR)               

Bwlch Height:  37.3m (LIDAR) 

Bwlch Grid Reference:  SH 53729 38357 (LIDAR) 

Drop:  20.5m (LIDAR) 

 

Myrddyn Phillips (May 2024)

 

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Hill Park (SM 955 102) - 30th summit relocation

Significant Name Changes post for Hill Park

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill prompted by detail produced by Joe Nuttall in his surface analysis programme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Myrddyn Phillips. 

LIDAR image of Hill Park (SM 955 102)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is now listed by is Hill Park, and this was derived from the Tithe map, and it is adjoined to the Garn Fawr group of hills which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned encircled by minor roads, with the A4076 road farther to its west, and the A477 road to its south-west, and has the village of Johnston towards the west.

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a 99m summit height positioned at SM 95593 10231, based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 31m of drop, based on the 99m summit spot height and an estimated c 68m bwlch height, based on interpolation of 5m contouring between 65m – 70m, resulting with the drop value being insufficient in relation to the summit height for consideration to Lesser Dominant status. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis gives the highest ground on this hill as 101.7m positioned at SM 95588 10281.  However, LIDAR contouring indicates this is a mound constituting disturbed ground, implying that it is not natural and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Hill Park (SM 955 102)

The height produced by LIDAR analysis to the highest remaining natural ground on this hill is 99.5m and this is positioned at SM 95585 10244, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the height produced by LIDAR analysis to the highest remaining natural ground on this hill is 99.5m and is positioned at SM 95585 10244, this position is close to where the 99m spot height appears on the contemporary Ordnance Survey 1:25,000 Explorer map, and is approximately 37 metres southward from where the mound is positioned. 

 

The full details for the hill are: 

Group:  Garn Fawr

Name:  Hill Park

OS 1:50,000 map:  157, 158

Summit Height:  99.5m (LIDAR)

Summit Grid Reference (New Position):  SM 95585 10244 (LIDAR)

Bwlch Height:  63.6m (LIDAR)

Bwlch Grid Reference:  SM 93281 10622 (LIDAR)

Drop:  35.9m (LIDAR)

Dominance:  36.16% (LIDAR)

 

Myrddyn Phillips (January 2024)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Field (SN 068 063) - 29th summit relocation

Significant Name Changes post for Field

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from detail produced by Joe Nuttall in his surface analysis progamme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Myrddyn Phillips. 

LIDAR image of Field (SN 068 063)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is now listed by is Field and this was derived from the Tithe map, and it is adjoined to the Mynydd Preseli group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its immediate north and the A4075 road to its west, and has the small community of Creseli (Cresselly) towards the west.

When the original Welsh 30-99m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a c 90m summit height, which is the height of the uppermost ring contour which appears on the contemporary Ordnance Survey 1:25,000 Explorer map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 91m summit height positioned at SN 06775 06382.

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis gives the highest ground on this hill as 90.7m positioned at SN 06823 06373.  However, this is a part of a raised hedge bank and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Field (SN 068 063)

The height produced by LIDAR analysis to the highest remaining natural ground on this hill is 90.1m and this is positioned at SN 06845 06360, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

The highest remaining natural ground on Field (Photo: Google Street View)

Therefore, the height produced by LIDAR analysis to the highest remaining natural ground on this hill is 90.1m and is positioned at SN 06845 06360, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 70 metres east south-eastward from where the originally listed summit was positioned and approximately 22 metres east south-eastward from where the high point of the raised hedge bank is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Preseli 

Name:  Field 

OS 1:50,000 map:  158

Summit Height:  90.1m (LIDAR) 

Summit Grid Reference (New Position):  SN 06845 06360 (LIDAR) 

Bwlch Height:  52.1m (LIDAR) 

Bwlch Grid Reference:  SN 08698 06251 & SN 08706 06253 & SN 08709 06255 (LIDAR) 

Drop:  37.9m (LIDAR) 

Dominance:  42.11% (LIDAR) 

 

Myrddyn Phillips (August 2023) 

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Black Acre (SN 292 146) - 28th summit relocation

Significant Name Changes post for Black Acre

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Black Acre (SN 292 146)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is now listed by is Black Acre and this was derived from the Tithe map, and it is adjoined to the Mynydd Pencarreg group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned with the A40 road to its north, the A4066 road to its west and a minor road to its east, and has the small town of Sanclêr (St Clears) towards the north-west.

When the original Welsh 30-99m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a summit height of c 60m, which is the uppermost Ordnance Survey map ring contour that appears on the 1:25,000 Explorer map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis gives ground on a raised field boundary as the highest on this hill, however protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Black Acre (SN 292 146)

The height produced by LIDAR analysis to the natural summit of this hill is 61.3m positioned at SN 29283 14648, and this position in relation to the raised field boundary comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to when the high point is positioned in a different field, to a different feature such as a conifer plantation, within a different map contour, a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 61.3m and this is to the natural summit of the hill which is positioned at SN 29283 14648, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 20 metres south-eastward from where the high point of the raised field boundary is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Pencarreg 

Name:  Black Acre 

OS 1:50,000 map:  159

Summit Height:  61.3m (LIDAR) 

Summit Grid Reference (New Position):  SN 29283 14648 (LIDAR) 

Bwlch Height:  29.6m (LIDAR) 

Bwlch Grid Reference:  SN 29308 15527 (LIDAR) 

Drop:  31.8m (LIDAR) 

Dominance:  51.80% (LIDAR) 

 

Myrddyn Phillips (October 2022)

 

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Ffynnon Ellis (SN 392 204) - 27th summit relocation

Significant Name Changes post for Ffynnon Ellis

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Ffynnon Ellis (SN 392 204)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is now listed by is Ffynnon Ellis and this was derived from the Tithe map, and it is adjoined to the Mynydd Pencarreg group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its north, and the B4312 and the A40 road to its south, and has the town of Caerfyrddin (Carmarthen) towards the immediate east.

When the original Welsh 30-99m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a summit height of 73m, based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map, which also indicates the presence of a covered reservoir. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR summit image of Ffynnon Ellis (SN 392 204)

LIDAR analysis gives a 73.7m height positioned at SN 39221 20463 to remaining natural ground close to the base of the elevated covered reservoir, the latter is discounted from the height of the hill as it is deemed a relatively recent man-made construct.  This position in relation to the covered reservoir comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to when the high point is positioned in a different field, to a different feature such as a conifer plantation, within a different map contour, a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 73.7m and this is to the remaining natural summit of the hill which is positioned at SN 39221 20463, this position is given a spot height on the contemporary Ordnance Survey 1:25,000 Explorer map, and is approximately 2m lower that the high point of the covered reservoir. 

 

The full details for the hill are: 

Group:  Mynydd Pencarreg 

Name:  Ffynnon Ellis 

OS 1:50,000 map:  145, 159

Summit Height:  73.7m (LIDAR) 

Summit Grid Reference (New Position):  SN 39221 20463 (LIDAR) 

Bwlch Height:  33.8m (LIDAR) 

Bwlch Grid Reference:  SN 39997 20345 (LIDAR) 

Drop:  39.9m (LIDAR) 

Dominance:  54.09% (LIDAR) 

 

Myrddyn Phillips (September 2022)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Caer Lan (SN 314 179) - 26th summit relocation

Significant Name Changes post for Caer Lan

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Caer Lan (SN 314 179)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is now listed by is Caer Lan and this was derived from the Tithe map, and it is adjoined to the Mynydd Pencarreg group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north, west and east, and the A40 road to its south, and has the small town of Sanclêr (St Clears) towards the west south-west.

When the original Welsh 30-99m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a summit height of c 75m, which is the uppermost Ordnance Survey map ring contour that appears on the 1:25,000 Explorer map.

When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimated c 78m summit height positioned at SN 31418 17940, based on interpolation of its uppermost 75m map ring contour. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis gives a 79.25m height positioned at SN 31377 17944 to ground on a raised field boundary as the highest on the hill, however protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Caer Lan (SN 314 179)

The height produced by LIDAR analysis to the natural summit of this hill is 78.8m positioned at SN 31408 17941, and this position in relation to the raised field boundary comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to when the high point is positioned in a different field, to a different feature such as a conifer plantation, within a different map contour, a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 78.8m and this is to the remaining natural summit of the hill which is positioned at SN 31408 17941, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 30 metres eastward from where the high point of the raised field boundary is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Pencarreg 

Name:  Caer Lan 

OS 1:50,000 map:  159

Summit Height:  78.8m (LIDAR) 

Summit Grid Reference (New Position):  SN 31408 17941 (LIDAR) 

Bwlch Height:  36.4m (LIDAR) 

Bwlch Grid Reference:  SN 30930 18268 (LIDAR) 

Drop:  42.4m (LIDAR) 

Dominance:  53.81% (LIDAR) 

 

Myrddyn Phillips (September 2022)

 

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Lan Uchaf (SN 526 230) - 25th summit relocation

Significant Name Changes post for Lan Uchaf

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Lan Uchaf (SN 526 230)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Lan Uchaf and this was derived from the Tithe map, and it is adjoined to the Mynydd Mallaen group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned encircled by minor roads with the A40 road farther to its south, and has the town of Llandeilo towards the east.

When the sub list was standardised and interpolated heights and drop values also included in the original Welsh 30-99m P30 list that was published on Geoff Crowder’s v-g.me website, this hill was listed with an estimated c 86m summit height positioned at SN 526 230, based on interpolation of its uppermost 80m ring contour. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis gives an 86.8m height positioned at SN 52695 23032 and SN 52697 23033 to ground on a raised field boundary as the highest on the hill, however protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Lan Uchaf (SN 526 230)

The height produced by LIDAR analysis to the natural summit of this hill is 86.7m positioned at SN 52675 23027, and this position in relation to the raised field boundary comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 86.7m and this is to the remaining natural summit of the hill which is positioned at SN 52675 23027, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 20 metres westward from where the raised field boundary is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Mallaen 

Name:  Lan Uchaf 

OS 1:50,000 map:  159

Summit Height:  86.7m (LIDAR) 

Summit Grid Reference (New Position):  SN 52675 23027 (LIDAR) 

Bwlch Height:  39.0m (LIDAR) 

Bwlch Grid Reference:  SN 53053 23453 & SN 53053 23455 (LIDAR) 

Drop:  47.7m (LIDAR) 

Dominance:  55.02% (LIDAR) 

 

Myrddyn Phillips (May 2022)

 

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Pt. 86.4m (SH 482 875) - 24th summit relocation

Significant Name Changes post for Pt. 86.4m

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Pt. 86.4m (SH 482 875)

The criteria for the list that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

The hill is being listed by the Point (Pt. 86.4m) notation as an appropriate name for it either from historic research or local enquiry has not been found, and it is adjoined to the Ynys Môn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the coast to its north-east, the A5025 road to its south-west and a minor road to its south-east, and has the village of Moelfre towards the east south-east. 

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was included in the Hills to be surveyed sub list, and included as a twin topped hill with the prioritised summit given at SH 484 876 with an accompanying note stating; Two tops of same height – other at SH 482 874. 

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with 29m of drop, based on the twin 86m summit spot heights that appear on the Ordnance Survey 1:25,000 Explorer map and the 57m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR summit image of Pt. 86.4m (SH 482 875)

The summit height produced by LIDAR analysis for these two tops is 86.379m positioned at SH 48231 87520 and 86.169m positioned at SH 48453 87717.  As LIDAR has split these twin map heighted tops and as the higher was the previously listed non-priority top this comes within the parameters of the Summit Relocations used within this page heading, these parameters are: 

The term Summit Relocations applies when the hill’s high point is found to be positioned; in a different field, within a different map contour, to a different feature such as in a conifer plantation, to a different point where a number of potential summit positions are within close proximity, a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct. 

Therefore, the summit height produced by LIDAR analysis is 86.4m and this is positioned at SH 48231 87520, this position is given an 86m spot height on contemporary Ordnance Survey 1:25,000 Explorer maps, and is approximately 240 metres south-westward from where the previously listed priority summit is positioned. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Pt. 86.4m 

OS 1:50,000 map:  114

Summit Height:  86.4m (LIDAR) 

Summit Grid Reference (New Position):  SH 48231 87520 (LIDAR)               

Bwlch Height:  57.0m (LIDAR) 

Bwlch Grid Reference:  SH 47995 86997 (LIDAR) 

Drop:  29.4m (LIDAR) 

 

Myrddyn Phillips (September 2021)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Bwlch y Fen & Tyddyn Gwyn (SH 417 783) - 23rd summit relocation

Hill Reclassifications post for Bwlch y Fen & Tyddyn Gwyn

Significant Name Changes post for Bwlch y Fen & Tyddyn Gwyn

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data and LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Bwlch y Fen & Tyddyn Gwyn (SH 417 783)

The criteria for the list that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

The name the hill is listed by is Bwlch y Fen & Tyddyn Gwyn and this was derived from the Tithe map, and it is adjoined to the Ynys Môn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with minor roads to its north, west and east, and the B5109 road to its south, and has the village of Gwalchmai towards the south-west. 

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was not included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category. 

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 21m of drop, based on the 89m summit spot height positioned at SH 41706 78330 that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 68m bwlch height based on interpolation of 5m contouring between 65m – 70m. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.  

The height produced by LIDAR analysis for the remaining natural summit is 88.150m and is positioned at SH 41738 78329, with LIDAR analysis giving a raised field boundary positioned at SH 41714 78319 a height of 88.169m, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are: 

The term Summit Relocations applies when the hill’s high point is found to be positioned; in a different field, within a different map contour, to a different feature such as in a conifer plantation, to a different point where a number of potential summit positions are within close proximity, a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct. 

LIDAR summit image of Bwlch y Fen & Tyddyn Gwyn

Therefore, the summit height produced by LIDAR analysis is 88.15m and this is positioned at SH 41738 78329, this position is relatively close to where the 89m spot height appears on the contemporary Ordnance Survey 1:25,000 Explorer map and importantly to the remaining natural summit of this hill as opposed to the slightly higher raised field boundary. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Bwlch y Fen & Tyddyn Gwyn 

OS 1:50,000 map:  114, 115

Summit Height:  88.15m (LIDAR) 

Summit Grid Reference (New Position):  SH 41738 78329 (LIDAR)               

Bwlch Height:  c 68m (interpolation) 

Bwlch Grid Reference:  SH 41140 80401 (interpolation) 

Drop:  c 20m (LIDAR summit and interpolated bwlch) 

 

Myrddyn Phillips (September 2021)

 

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Pen y Graig Wen (SH 446 879) - 22nd summit relocation

Hill Reclassification post for Pen y Graig Wen

Significant Height Revisions post for Pen y Graig Wen

Significant Name Changes post for Pen y Grain Wen

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Pen y Graig Wen (SH 446 879)

The criteria for the list that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

The name the hill is listed by is Pen y Graig Wen and this was derived from the Tithe map and it is adjoined to the Ynys Môn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the coast to its east, minor roads to its north, south and east and the B5111 road to its west, and has the village of Rhos-y-bol towards the west north-west. 

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was not included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category. 

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 24m of drop, based on an estimated c 92m summit height positioned at SH 44769 87804 and an estimated c 68m bwlch height, with both heights based on interpolation of 5m contouring that appears on the Ordnance Survey 1:25,000 Explorer map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

The summit height produced by LIDAR analysis is 94.3m and is positioned at SH 44637 87986, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are: 

The term Summit Relocations applies when the hill’s high point is found to be positioned; in a different field, to a different feature such as in a conifer plantation, placed within a different map contour, to a different point where a number of potential summit positions are within close proximity, or when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist. 

Therefore, the summit height produced by LIDAR analysis is 94.3m and this is positioned at SH 44637 87986, this position is not given a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and is approximately 225 metres north-westward from where the previously listed summit is positioned. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Pen y Graig Wen 

OS 1:50,000 map:  114

Summit Height:  94.3m (LIDAR) 

Summit Grid Reference (New Position):  SH 44637 87986 (LIDAR) 

Bwlch Height:  68.2m (LIDAR) 

Bwlch Grid Reference:  SH 45162 88579 (LIDAR) 

Drop:  26.1m (LIDAR) 

 

Myrddyn Phillips (August 2021)

 

 

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Tyddyn Gwydryn Llain Fan (SH 495 681) - 21st summit relocation

Hill Reclassifications post for Tyddyn Gwydryn Llain Fan

Significant Height Revisions post for Tyddyn Gwydryn Llain Fan

Significant Name Changes post for Tyddyn Gwydryn Llain Fan

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Tyddyn Gwyfryn Llain Fan (SH 495 681)

The criteria for the list that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

The name the hill is listed by is Tyddyn Gwydryn Llain Fan and this was derived from the Tithe map, and it is adjoined to the Ynys Môn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with its summit adjacent to the A4080 road, and has the village of Brynsiencyn towards the south-west. 

When the original 30-99m height band of Welsh P30hills were published on Geoff Crowder’s v-g.me website this hill was not included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category. 

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 26m of drop based on the 59m spot height adjoined to a triangulation pillar positioned at SH 49980 68424 and the 59m spot height positioned at SH 50109 68526 and an estimated c 33m bwlch height based on interpolation of 5m contouring between 30m – 35m that appear on the Ordnance Survey 1:25,000 Explorer map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

The summit height produced by LIDAR analysis is 60.4m and is positioned at SH 49584 68102, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are: 

The term Summit Relocations applies when the hill’s high point is found to be positioned; in a different field, to a different feature such as in a conifer plantation, placed within a different map contour, to a different point where a number of potential summit positions are within close proximity, or when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist. 

Therefore, the summit height produced by LIDAR analysis is 60.4m and this is positioned at SH 49584 68102, this position is not given a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and is approximately 400 metres south-westward from where the previously listed summit is positioned.

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Tyddyn Gwydryn Llain Fan 

OS 1:50,000 map:  114, 115

Summit Height:  60.4m (LIDAR) 

Summit Grid Reference (New Position):  SH 49584 68102 (LIDAR) 

Bwlch Height:  31.9m (LIDAR) 

Bwlch Grid Reference:  SH 51324 71408 (LIDAR) 

Drop:  28.5m (LIDAR) 

 

Myrddyn Phillips (May 2021)

 

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Ynys Fach (SN 668 951) - 20th summit relocation

Hill Reclassifications post for Ynys Fach

Significant Height Revisions post for Ynys Fach

Significant Name Changes post for Ynys Fach

 

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived by Joe Nuttall who produced a summit analysis programme using LIDAR, and then by LIDAR analysis initially conducted by Jim Bloomer and subsequently by Myrddyn Phillips. 

LIDAR image of Ynys Fach (SN 668 951)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 30-99m Twmpau by Myrddyn Phillips

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is now listed by is Ynys Fach, and it is adjoined to the Pumlumon group of hills which are situated in the north-western part of Mid and West Wales (Region B, Sub-Region B2), and it has the A487 road to its south-east and the town of Machynlleth towards the north-east. 

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was included in the Hills to be surveyed sub list that accompanied the main P30 list, as it was considered not to meet the criteria then used in the main P30 category. 

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 27m of drop based on an estimated c 34m summit height positioned at SN 670 948 and an estimated c 7m bwlch height, with both values based on interpolation of 10m contouring that appears on the Ordnance Survey 1:25,000 Explorer map, with 30m being the uppermost contour given the hill on this map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

The summit height produced by LIDAR analysis is 43.5m and is positioned at SN 66845 95141, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are: 

The term Summit Relocations applies when the hill’s high point is found to be positioned; in a different field, to a different feature such as in a conifer plantation, placed within a different map contour, to a different point where a number of potential summit positions are within close proximity, or when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist. 

Therefore, the summit height produced by LIDAR analysis is 43.5m and this is positioned at SN 66845 95141, this position is not given a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and is approximately 300 metres north north-westward from where the previously listed summit is positioned.

 

The full details for the hill are: 

Group:  Pumlumon 

Name:  Ynys Fach 

OS 1:50,000 map:  135

Summit Height:  43.5m (LIDAR) 

Summit Grid Reference (New Position):  SN 66845 95141 (LIDAR) 

Bwlch Height:  2.1m (LIDAR) 

Bwlch Grid Reference:  SN 67483 95096 (LIDAR) 

Drop:  41.3m (LIDAR) 

Dominance:  95.10% (LIDAR) 

 

Myrddyn Phillips (April 2021)

 

 

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Parkwall Hill (ST 499 906) - 19th summit relocation

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Parkwall Hill (ST 499 906)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

The 30-99m Twmpau by Myrddyn Phillips

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format.

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Parkwall Hill, and it is adjoined to the Gwent Is Coed group of hills which are situated in the south-eastern part of South Wales (Region C, Sub-Region C3), and it is positioned with the M48 motorway to its north and the A48 road to its south, and has the city of Casnewydd (Newport) towards the west.

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was included in the main P30 list, and listed with a 53m summit height based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map and which is positioned at ST 49702 90594.

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

The summit height produced by LIDAR analysis is 53.8m and is positioned at ST 49926 90619, this is not a dramatic difference in position compared to some relocations, but it does come within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the hill’s high point is found to be positioned; in a different field, to a different feature such as in a conifer plantation, placed within a different map contour, to a different point where a number of potential summit positions are within close proximity, or when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 53.8m and this is positioned at ST 49926 90619, this position is not given a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and is approximately 225 metres eastward from where the previously listed summit is positioned. 

The full details for the hill are:

Group:  Gwent Is Coed

Name:  Parkwall Hill

OS 1:50,000 map:  162, 172

Summit Height:  53.8m (LIDAR, natural summit)

Summit Grid Reference (new position):  ST 49930 90616 & ST 49925 90613 & ST 49926 90619 (LIDAR)

Bwlch Height:  21.4m (LIDAR)

Bwlch Grid Reference:  ST 49863 91222 (LIDAR)

Drop:  32.5m (LIDAR)

Dominance:  60.31% (LIDAR)

Myrddyn Phillips (October 2020)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Ifton Great Wood (ST 455 894) - 18th summit relocation

Hill Reclassifications post for Ifton Great Wood

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Ifton Great Wood (ST 455 894)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

The 30-99m Twmpau by Myrddyn Phillips

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format.

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Ifton Great Wood, and it is adjoined to the Gwent Is Coed group of hills which are situated in the south-eastern part of South Wales (Region C, Sub-Region C3), and it is positioned with the A48 road to its north and the M48 motorway to its south, and has the city of Casnewydd (Newport) towards the west.

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was included in the Hills to be surveyed sub list that accompanied the main P30 list, and listed with a 82m summit height based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map and which is positioned at ST 45459 89470.

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR summit image of Ifton Great Wood

The summit height produced by LIDAR analysis is 84.3m and is positioned at ST 45565 89483, this is not a dramatic difference in position compared to some relocations, but it does come within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the hill’s high point is found to be positioned; in a different field, to a different feature such as in a conifer plantation, placed within a different map contour, to a different point where a number of potential summit positions are within close proximity, or when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 84.3m and this is positioned at ST 45565 89483, this position is not given a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and is approximately 110 metres eastward from where the previously listed summit is positioned. 

The full details for the hill are:

Group:  Gwent Is Coed

Name:  Ifton Great Wood

OS 1:50,000 map:  171, 172

Summit Height:  84.3m (LIDAR)

Summit Grid Reference (new position):  ST 45565 89483 (LIDAR)

Bwlch Height:  51.2m (LIDAR)

Bwlch Grid Reference:  ST 43958 89132 (LIDAR)

Drop:  33.1m (LIDAR)

Dominance:  39.25% (LIDAR)

Myrddyn Phillips (October 2020)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Waltwood Hill (ST 386 885) - 17th summit relocation

Significant Height Revisions post for Waltwood Hill

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Waltwood Hill (ST 386 885)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format.

The name the hill is listed by is Waltwood Hill, and it is adjoined to the Gwent Is Coed group of hills which are situated in the south-eastern part of South Wales (Region C, Sub-Region C3), and it is positioned with the M4 motorway to its north, the A48 road to its west and the A4810 road to its south, and has the city of Casnewydd (Newport) towards the west.

When the original Welsh 30-99m P30 list was published on Geoff Crowder’s v-g.me website this hill was listed with a 68m summit height based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map and which is positioned at ST 38637 88605.

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR summit image of Waltwood Hill

The summit height produced by LIDAR analysis is 70.2m and is positioned at ST 38646 88595.  Although this position is almost identical to that of the spot height, LIDAR confirms a natural summit compared to the spot height position which is on the side of a covered reservoir.  The above detail comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the hill’s high point is in a different field, or where a number of potential summit positions are within close proximity and the highest point is not where previously given, or when it is positioned to a different feature such as in a conifer plantation, or when the high point of the hill is placed within a different map contour, or when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 70.2m and this is positioned at ST 38646 88595, although close in position to where the spot height appears on the 1:25,000 Explorer map, LIDAR has confirmed an intact and natural summit compared to the higher covered reservoir that is considered a recent man-made construct and therefore does not qualify as being considered for the height of this hill.

The full details for the hill are:

Group:  Gwent Is Coed

Name:  Waltwood Hill

OS 1:50,000 map:  171

Summit Height:  70.2m (LIDAR)

Summit Grid Reference (new position):  ST 38646 88595 (LIDAR)

Bwlch Height:  21.7m (LIDAR)

Bwlch Grid Reference:  ST 39426 89069 and ST 39433 89070 (LIDAR)

Drop:  48.5m (LIDAR)

Dominance:  69.07% (LIDAR)

Myrddyn Phillips (August 2020)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Ynys Bery (SM 701 219) - 16th summit relocation

There has been confirmation of the higher summit of a twin map topped hill that is being detailed under the Summit Relocations heading, and the hill is listed in the 30-99m Twmpau, Y Trechol – The Dominant Hills of Wales and Y Pellennig – The Remotest Hills of Wales, with the summit height and its location confirmed by LIDAR analysis conducted by Aled Williams.

LIDAR image of Ynys Bery.  1m contour (black), 10m contour (red) and sea level (yellow)

The criteria for the three listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

Y Pellennig – The Remotest Hills of Wales - Welsh hills whose summit is at least 2.5km from the nearest paved public road and the hill has a minimum 15m of drop, the list is a joint compilation between Myrddyn Phillips and Aled Williams and is available as a downloadable e-booklet or print-booklet version on Mapping Mountains Publications with the up-to-date master list available on the Mapping Mountains site in Google Doc format.

The name of the hill is Ynys Bery and as its name implies it is an island, and it is adjoined to the Carn Llidi group of hills which are situated in the south-western part of Mid and West Wales (Region B, Sub-Region B4), and is positioned to the south of the larger Ynys Dewi.

This hill was originally listed in the Welsh 30-99m P30 hills published on Geoff Crowder’s v-g.me website, with a 71m summit height and an accompanying note stating; Two tops of same height.  The 71m summit height appears as a spot height given to two separate tops on the Ordnance Survey 1:25,000 Explorer map with these positioned at SM 70058 21863 and SM 70183 21965.

Extract from the Ordnance Survey 1:25,000 Explorer map

Extract from the Ordnance Survey Vector Map Local hosted on the Geograph website

The details for this hill were reassessed when the Ordnance Survey Vector Map Local hosted on the Geograph website became available online; this map is entitled the Interactive Coverage Map and the two twin map heighted 71m summits were again shown.

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis confirms that the north-easterly of these two summits is the higher and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.

Therefore, the summit height produced by LIDAR analysis is 72.0m and is positioned at SM 70182 21959, this position is given a 71m spot height on the Ordnance Survey 1: 25,000 Explorer map and is approximately 150 metres north-east from where the other twin map heighted summit is positioned which LIDAR analysis gives as 71.9m at SM 70056 21859.

The full details for the hill are:

Group:  Carn Llidi

Name:  Ynys Bery

OS 1:50,000 map:  157

Summit Height:  72.0m (LIDAR)

Summit Grid Reference (new position):  SM 70182 21959 (LIDAR)

Bwlch Height:  N/A, sea level

Bwlch Grid Reference:  N/A, sea level

Drop:  72.0m (LIDAR)

Dominance:  100.00% (LIDAR)

Remoteness:  3.925 km

Myrddyn Phillips and Aled Williams (July 2019)

© Crown: CHERISH PROJECT 2019. Produced with EU funds through the Ireland Wales Co-operation Programme 2014-2020. All material made freely available through the Open Government Licence.

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Plas Gwyn (SH 524 817) - 15th summit relocation

Survey post for Plas Gwyn

Significant Name Changes post for Plas Gwyn

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis, and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the latter taking place on the 22^nd October 2018.

Plas Gwyn (SH 524 817)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

The name of the hill is Plas Gwyn and this was derived from local enquiry, and it is adjoined to the Ynys Môn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it has the A5025 road to its west and the coast to its north and east, and overlooks Traeth-coch (Red Wharf Bay) to its south-east, and has the village of Benllech towards its north-west.

This hill was first listed in the original Welsh 30-99m P30 list published on Geoff Crowder’s v-g.me website with a 78m summit height positioned at SH 526 817 and which is based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map.

Extract from the Ordnance Survey Vector Map Local hosted on the Geograph website with the cursor indicating the position of the newly relocated summit

Prior to the Trimble GeoXH 6000 summit survey the details for this hill were analysed with LIDAR.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR image of the summit of Plas Gwyn

The height produced by LIDAR analysis and the Trimble GeoXH 6000 summit survey is 76.1m which is positioned at SH 52494 81743, this is not a dramatic difference in position compared to some relocations, but it does come within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.

The Trimble GeoXH 6000 gathering data at the new summit position of Plas Gwyn

The Trimble GeoXH 6000 gathering data at the old summit position of Plas Gwyn

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 76.1m and is positioned at SH 52494 81743, this position is not given a spot height on contemporary Ordnance Survey maps and is approximately 110 metres west from where the 78m spot height appears on the Ordnance Survey 1:25,000 Explorer map and which was the position of the previously listed summit and surveyed as being 75.7m in height.

The full details for the hill are:

Group:  Ynys Môn

Name:  Plas Gwyn

OS 1:50,000 map:  114, 115

Summit Height:  76.1m (converted to OSGM15)

Summit Grid Reference (new position):  SH 52494 81743

Bwlch Height:  41.9m (LIDAR)

Bwlch Grid Reference:  SH 52209 81404 (LIDAR)

Drop:  34.2m (Trimble summit and LIDAR bwlch)

Dominance:  44.91% (Trimble summit and LIDAR bwlch)

For details on the survey that confirmed the summit relocation of this hill

Myrddyn Phillips (May 2019)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Yr Orsedd (SH 299 270) - 14th summit relocation

Survey post for Yr Orsedd

Hill Reclassifications post for Yr Orsedd

Significant Name Changes post for Yr Orsedd

There has been confirmation of a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis, and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the latter taking place on the 3^rd October 2018.

Yr Orsedd (SH 299 270)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

The name of the hill is Yr Orsedd, and this was derived from local enquiry, and it is adjoined to the Pen Llŷn group of hills, which are situated in the western part of North Wales (Region A, Sub-Region A1), and the hill is encircled by minor roads with the coast to its south-west and east, and has the village of Abersoch towards its north-east.

As the summit of this hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so the easiest approach is via the east using gates to access the summit.

This hill was first listed in the Hills to be surveyed sub-list that accompanied the original Welsh P30 list published on Geoff Crowder’s v-g.me website, with a 64m summit height which is positioned at SH 295 266 and appeared as a spot height on the Ordnance Survey 1:25,000 Explorer map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

When this list was standardised with interpolated heights and drop values included this hill was listed with c 31m of drop based on the 64m summit spot height and an estimated bwlch height of c 33m based on interpolation of 10m bwlch contouring, and the locally known name for this hill is Bryn Tŷ Newydd.

Bryn Tŷ Newydd (SH 295 265)

The details for this hill were reassessed when the Ordnance Survey Interactive Coverage Map hosted on the Geograph website became available online, and this map has a 66m spot height at SH 299 270 which is adjoined to the hill to the north-east, which only has an uppermost 60m ring contour on the 1:25,000 Explorer map.  Therefore the summit position of the listed hill was relocated and its drop value increased accordingly, with the Interactive Coverage Map also giving the south-westerly hill a second 64m map heighted summit.

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website

Prior to the Trimble GeoXH 6000 summit survey this hill and its adjoining south-westerly 64m twin map heighted hill were analysed via LIDAR, and this confirmed that the north-easterly summit is the higher.

The height produced by the Trimble GeoXH 6000 survey to the summit of this hill is 67.5m and is positioned at SH 29952 27038, as opposed to the 64.2m LIDAR height for the higher of the two 64m Geograph summits to the south-west and which is positioned at SH 29571 26573.  This confirms the hill’s summit position compared to where previously listed, and it comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 67.5m and is positioned at SH 29952 27038, this position is given a 66m spot height on the Ordnance Survey Interactive  Coverage Map hosted on the Geograph website and is approximately 550 metres north-east from where the previously listed summit is positioned.

The Trimble GeoXH 6000 gathering data at the summit of Yr Orsedd

The full details for the hill are:

Group:  Pen Llŷn

Name:  Yr Orsedd

OS 1:50,000 map:  123

Summit Height:  67.5m (converted to OSGM15)

Summit Grid Reference (new position):  SH 29952 27038

Bwlch Height:  32.0m (LIDAR)

Bwlch Grid Reference:  SH 29808 27337 (LIDAR)

Drop:  35.4m (Trimble summit and LIDAR bwlch)

Dominance:  52.52% (Trimble summit and LIDAR bwlch)

For details on the summit survey of this hill

Myrddyn Phillips (February 2019)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Penrhos Garnedd (SH 560 702) - 13th summit relocation

Survey post for Penrhos Garnedd

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, due to LIDAR analysis initially conducted by Aled Williams, with subsequent LIDAR analysis and a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips, with the latter taking place on the 30^th September 2018.

The summit of Penrhos Garnedd (SH 560 702)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

The name of the hill is Penrhos Garnedd, and it is adjoined to the Gyderau group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the A55 to its south, the A487 to its north-west and the A4087 road to its east, and has the city of Bangor to its north-east.

As the summit of this hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so a public footpath approaches the summit from its north-west.

This hill was first listed in the original Welsh P30 list published on Geoff Crowder’s v-g.me website with a c 95m summit height positioned at SH 559 703.  With the summit height given as c 90m in the initial draft compilation with an accompanying note stating Three points of same height, this refers to the hill having three uppermost 90m ring contours on the Ordnance Survey 1:25,000 Outdoor Leisure map number 17 of the day.  The height of this hill was amended when the Ordnance Survey 1:25,000 Explorer map number 263 became available and listed as c 95m with the grid reference centred in this ring contour as opposed to using the 95m spot height positioned at SH 55874 70070 that appears in it.

Extract from the Ordnance Survey 1:25,000 Explorer map

Prior to the Trimble GeoXH 6000 survey this hill’s summit and bwlch contours were analysed with LIDAR by Aled Williams, who kindly forwarded these details to me and suggested that the hill should be surveyed with the Trimble.  I then analysed this hill via LIDAR and consulted logged reports on the Hill Bagging website of past visits.  This resulted in three points noted to be surveyed, with a fourth point also surveyed when on the hill.

LIDAR image of Penrhos Garnedd

Therefore, four data sets were taken with the Trimble GeoXH 6000 from the summit area of this hill, resulting in:

1^st survey:  93.388m at SH 55902 70421 (Bryn Ogwen road)

2^nd survey:  93.077m at SH 55908 70429 (Bryn Ogwen road)

3^rd survey:  94.045m at SH 56027 70234 (summit)

4^th survey:  92.540m at SH 55892 70474 (crossroads at Ffordd Penrhos and Coed y Maes)

The height produced by the Trimble GeoXH 6000 survey to the summit of this hill is 94.0m and is positioned at SH 56027 70234, this is not a dramatic difference in position compared to where previously listed, but it does come within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.

The Trimble GeoXH 6000 set-up position at the summit of Penrhos Garnedd

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 94.0m and is positioned at SH 56027 70234, this position is not given a spot height on contemporary Ordnance Survey maps and is approximately 200 metres north-east from where the 95m spot height appears on the Ordnance Survey 1:25,000 Explorer map.

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website with the circled position indicating the new summit position

The full details for the hill are:

Group:  Glyderau

Name:  Penrhos Garnedd

OS 1:50,000 map:  114, 115

Summit Height:  94.0m (converted to OSGM15)

Summit Grid Reference (new position):  SH 56027 70234

Bwlch Height:  40.4m (LIDAR)

Bwlch Grid Reference:  SH 56305 70029 (LIDAR)

Drop:  53.7m (Trimble summit and LIDAR bwlch)

Dominance:  57.05% (Trimble summit and LIDAR bwlch)

My thanks to Aled Williams for his initial LIDAR analysis

For details on the survey that relocated the summit position of this hill

Myrddyn Phillips (February 2019)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Bryn (SH 426 361) - 12th summit relocation

Survey post for Bryn

Hill Reclassifications post for Bryn

Significant Name Changes post for Bryn

There has been a Summit Relocation to a hill that is now listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the hill suggested as a P30 by Chris Pearson in February 2018 and its status confirmed by LIDAR analysis conducted by Chris Crocker.  The hill was subsequently analysed by LIDAR and surveyed with the Trimble GeoXH 6000 by Myrddyn Phillips, with the latter taking place on the 10^th September 2018.

LIDAR image of the summit of Bryn

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

The locally known name of the hill is Bryn, and this is the name it is now listed by, and it is adjoined to the Pen Llŷn group of hills, which are situated in the western part of North Wales (Region A, Sub-Region A1), and is positioned overlooking the sea to its south and the A 497 road to its north, and has the town of Pwllheli towards the west.

As the summit of this hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so a public footpath approaches the hill from its north and access to the summit is relatively easy from here via its north-west which avoids the majority of gorse on its upper part.

When this hill was first listed in the Hills to be surveyed sub list that accompanied the 30-99m height band of hills in the original Welsh P30 list published on Geoff Crowder’s v-g.me website, it was listed with a 36m summit height which appears as a spot height on the Ordnance Survey 1:25,000 Explorer map and is positioned at SH 42664 36179.

Prior to the Trimble GeoXH 6000 survey this hill’s summit and bwlch contours were analysed with LIDAR, with the conclusion that the hill is not a natural P30 as LIDAR bwlch contouring implies that the natural bwlch would once have been over 7m in height.  This bwlch is now reduced in height due to a railway cutting. 

An appropriate name for the hill was also researched via the Tithe map, finding that the upper section of the hill which now comprises one field, used to comprise two, with the boundary between each showing as a slight elevation on LIDAR.  This boundary although old, is not ancient, and would be a man-made construction.  LIDAR also shows that the natural summit of this hill still exists, close to the old field boundary.  Therefore I wanted to take data sets from the slightly raised field boundary, and the natural summit with LIDAR giving two potential positions for this, with one adjacent to the old field boundary and the other a few metres distant from it.

Therefore, three data sets were taken with the Trimble GeoXH 6000 from the summit area of this hill, resulting in:

1^st survey:  36.750m at SH 42673 36171 (raised old field boundary)

2^nd survey:  36.5965m at SH 42668 36171 (average of two surveys)

3^rd survey:  36.675m at SH 42656 36173 (natural summit)

The height produced by the Trimble GeoXH 6000 survey to the natural summit of this hill is 36.7m and is positioned at SH 42656 36173, this is not a dramatic difference in position compared to where the 36m spot height appears on the Ordnance Survey 1:25,000 Explorer map, but it does come within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.

The Trimble GeoXH 6000 gathering data at the summit of Bryn

Therefore, the natural summit height produced by the Trimble GeoXH 6000 survey is 36.7m and is positioned at SH 42656 36173, this is relatively close to where the 36m spot height of this hill is positioned and is approximately 17 metres from where the raised old field boundary is situated, and as this is considered a relatively recent man-made construct it is not considered as a part of this hill’s height.

The full details for the hill are:

Group:  Pen Llŷn

Name:  Bryn

OS 1:50,000 map:  123

Summit Height:  36.7m (converted to OSGM15) (natural summit)

Summit Grid Reference:  SH 42656 36173 (natural summit)

Bwlch Height:  6.6m (LIDAR)

Bwlch Grid Reference:  SH 43103 36535 (LIDAR) 

Drop:  30.0m (Trimble summit and LIDAR bwlch)

Dominance:  81.88% (Trimble summit and LIDAR bwlch)

For details on the survey that relocated the summit position of this hill

Myrddyn Phillips (January 2019)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Cae Ffwyn Uchaf (SN 588 005) - 11th summit relocation

Significant Name Changes post for Cae Ffwyn Uchaf

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, its location, drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Cae Ffwyn Uchaf

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

The name of the bounded land where the summit of this hill is situated is Cae Ffwyn Uchaf and this was derived from the Tithe map, and it is the name this hill is now listed by.  The hill is adjoined to the Mynydd Penlle’rcastell group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C1), and is positioned with the B 4296 immediately to its east with the M 4 and the Afon Lliw beyond, and has the town of Gorseinon towards the south.

As the summit of this hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so it is positioned relatively close to a B road which could give access towards the summit from its east.

When this hill was originally listed as a P30 and published in the 30-99m height band of hills on Geoff Crowder’s v-g.me website, and drop values later added it was listed with c 34m of drop based on the 67m spot height that appears on the Ordnance Survey 1:50,000 Landranger map at SN 586 998 and an estimated c 33m bwlch height.

Extract from the Ordnance Survey 1:50,000 Landranger map

The position of this hill’s summit was re-evaluated when the Ordnance Survey Interactive Coverage Map hosted on the Geograph website became available online, this map showed a 67m spot height positioned at SN 588 005.

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website

However, it was only with the advent of LIDAR that the high point of this hill could be confirmed, with the summit height produced by LIDAR analysis being 66.6m at SN 58825 00532, with LIDAR giving 65.9m at SS 58625 99765 to the position of the previously listed summit.  The position of the new listed summit position in relation to that previously given comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

LIDAR image of the old listed summit position

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.

The summit height produced by LIDAR analysis is 66.6m and is positioned at SN 58825 00532, this position is close to where the 67m spot height appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website, and it is approximately 750 metres north from where the previously listed summit is positioned.  With the caveat that the previously listed summit has a covered reservoir positioned at or close to it, and as this is considered a relatively recent man-made construct it is not considered as a part of this hill’s height.

   

The full details for the hill are:

Group:  Mynydd Penlle’rcastell

Name:  Cae Ffwyn Uchaf

OS 1:50,000 map:  159

Summit Height:  66.6m (LIDAR)

Summit Grid Reference (new position):  SN 58825 00532 (LIDAR)

Bwlch Height:  36.0m (LIDAR, natural bwlch)

Bwlch Grid Reference:  SN 59731 00951 (LIDAR, natural bwlch)

Drop:  30.6m (LIDAR)

Dominance:  45.90% (LIDAR)

My thanks to Aled Williams for helping to decipher the Tithe name given to the bounded land where the summit of this hill is situated

Myrddyn Phillips (January 2019)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Pwlldu Head (SS 569 865) - 10th summit relocation

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, drop and status of the hill being confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Pwlldu Head

The criteria for the two lists that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those addition Welsh P30 hills whose prominence is 33.33% or more and below 50% of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

The name of the hill is Pwlldu Head, and it is adjoined to the Gŵyr group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C1), and it is positioned overlooking the south Wales coast, and has the village of Melin y Parc (Parkmill) towards the north-west.

As the summit of the hill is a part of open access land it can be approached from most directions, with the open access land stretching to the north-west and north north-east of the summit and public footpaths approaching this land and that of the summit from the north.

Prior to LIDAR analysis this hill was listed with 35m of drop based on the 97m height given to a triangulation pillar positioned at SS 57003 86690 and the 62m bwlch spot height that appear on the Ordnance Survey 1:25,000 Explorer map, and it is the position of the triangulation pillar that had been listed for that of the summit.

LIDAR summit image of Pwlldu Head

The summit height produced by LIDAR analysis is 97.6m at SS 56933 86561 and its position in relation to that previously given comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.

The summit height produced by LIDAR analysis is 97.6m and is positioned at SS 56933 86561, this position is not given a spot height on contemporary Ordnance Survey maps and is approximately 130 metres south south-west from where the 97m spot height adjoined to the triangulation pillar appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.  

The Ordnance Survey Interactive Coverage Map hosted on the Geograph website showing the summit position in relation to where the trig pillar is positioned

The full details for the hill are:

Group:  Gŵyr

Name:  Pwlldu Head

OS 1:50,000 map:  159

Summit Height:  97.6m (LIDAR)

Summit Grid Reference (new position):  SS 56933 86561 (LIDAR)

Bwlch Height:  62.2m (LIDAR)

Bwlch Grid Reference:  SS 56191 88507 (LIDAR)

Drop:  35.5m (LIDAR)

Dominance:  36.32% (LIDAR)

Myrddyn Phillips (December 2018)






Mapping Mountains - Summit Relocations - 30-99m Twmpau

Broughton Burrows (SS 413 927) - 9th summit relocation

Significant Height Revisions post for Broughton Burrows

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height and drop of the hill being confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Broughton Burrows

The criteria for the two lists that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those addition Welsh P30 hills whose prominence is 33.33% or more and below 50% of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

LIDAR image of Broughton Burrows showing the summit and connecting bwlch

The name of the hill is Broughton Burrows, and it is adjoined to the Gŵyr group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C1), and it is positioned at the western end of the Gŵyr, and has the small community of Llangynydd towards the south-east.

Although the summit of this hill is not a part of open access land, and as such permission to visit should be sought, there is general acceptance for people to visit, with the nearest public footpath encircling the summit of the hill which comprises a dune system.

Close up LIDAR summit image of Broughton Burrows

Prior to LIDAR analysis and the inspection of 5m contouring on OS Maps, which is the recent replacement for OS Get-a-map, this hill was listed with c 32m of drop and 65.31% dominance based on the 49m spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an interpolated bwlch height of c 17m based on what was thought to be bwlch contouring between 15m – 20m.  However, as this hill is a part of a dune system this map did not show continuous contours on either the summit or bwlch area of this hill.

Extract from OS Maps

The summit height produced by LIDAR analysis is 61.9m at SS 41391 92781 and its position in relation to that previously given comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.

The summit height produced by LIDAR analysis is 61.9m and is positioned at SS 41391 92781, this position is not given a spot height on contemporary Ordnance Survey maps and is approximately 450 metres south-east from where the 49m spot height appears on the Ordnance Survey 1:25,000 Explorer map.  

The Ordnnance Survey Interactive Coverage map hosted on the Geograph website showing the summit position in relation to where the 49m spot height appears

The full details for the hill are:

Group:  Gŵyr

Name:  Broughton Burrows

OS 1:50,000 map:  159

Summit Height:  61.9m (LIDAR)

Summit Grid Reference (new position):  SS 41391 92781 (LIDAR)

Bwlch Height:  17.4m (LIDAR)

Bwlch Grid Reference:  SS 41739 92663 (LIDAR)

  

Drop:  44.5m (LIDAR)

Dominance:  71.95% (LIDAR)

Myrddyn Phillips (December 2018)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Park Quarry (SN 428 120) - 8th summit relocation

Significant Name Changes post for Park Quarry

There has been a Summit Relocation to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit and bwlch height and position confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Park Quarry

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those addition Welsh P30 hills whose prominence is 33.3% or more and below 50% of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

The name of the bounded land where the summit of the hill is situated is Park Quarry and this was derived from the Tithe map, and it is adjoined to the Mynydd Sylen group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C1), and is positioned with the stream valley of the Gwendraeth Fach to the south and east, and the A 484 road to the west, and has the small town of Cydweli (Kidwelly) towards the south.

As this hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so the most convenient approach is from the farm of Ystrad-fawr which is to the west south-west of the summit.

Prior to LIDAR analysis this hill was listed with c 47m of drop based on the 93m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 46m based on interpolation of bwlch contouring between 45m – 50m. 

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website showing one of the two equal heighted LIDAR summit positions in relation to the position of the spot height

The position of the 93m spot height appears at a field boundary that comprises a raised hedge which is considered to be a relatively recent man-made construct, therefore if a natural summit exists for this hill, even if lower than the hedge bank, the listed summit would be given to this position.

1m DTM LIDAR analysis gives the following:

Raised hedge bank:  93.999m at SN 42874 12092

Natural summit:  93.919m at SN 42853 12091 and SN 42859 12091

LIDAR image for Park Quarry showing the natural summit left of centre and the high point of the raised hedge bank in the centre of the image

Therefore, the height produced by 1m DTM LIDAR analysis for the natural summit of this hill is 93.9m and is positioned at SN 42853 12091 and SN 42859 12091.  These positions are not given a spot height on Ordnance Survey maps and are 21 metres and 15 metres respectively, west from where the high point of the raised hedge bank is positioned and approximately 30 metres from where the 93m spot height appears on the ground.

The full details for the hill are:

Group:  Mynydd Sylen

Name:  Park Quarry

Summit Height:  93.9m (LIDAR)

OS 1:50,000 map:  159

Summit Grid Reference (New Position):  SN 42853 12091 and SN 42859 12091 (LIDAR)  

Drop:  48.5m (LIDAR)

Dominance:  51.63% (LIDAR) 

Myrddyn Phillips (November 2018)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Cae Benglog (SH 316 380) - 7th summit relocation

Hill Reclassfications post for Cae Benglog

Significant Name Changes post for Cae Benglog

There has been a Summit Relocation to a hill that is now listed in the 30-99m Twmpau, with the summit height and its position, drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

The criteria for this list are:

30-99m Twmpau – Welsh hills at and above 30m and below 100m in height that have a minimum 30m of drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at and above 30m and below 100m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The name of the bounded land where the summit of this hill is situated is Cae Benglog with these details derived from the Tithe map and the hill is adjoined to the Pen Llŷn group of hills, which is situated in the north-west part of North Wales (Region A, Sub-Region A1), and is positioned overlooking the A 497 road which is to its north-east and has the small community of Morfa Nefyn t0 its north-west and the town of Pwllheli towards the south-east.

If wanting to visit the hill permission to do so should be sought as it is not a part of designated open access land, with the nearest public footpath close to the summit to its east.

This hill did not appear in the accompanying Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website as it did not meet the criteria for this sub category; however this sub list has now been standardised including the addition of interpolated drop values and heights.

Prior to LIDAR analysis this hill was listed with an estimated c 19m of drop based on the 86m spot height positioned at SH 31361 38368 on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 67m based on bwlch contouring at 5m intervals and between 65m – 70m on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.

Extract from the Ordnance Survey 1:25,000 Explorer map

Extract from OS Maps

The two positions of note and their heights relating to the summit of this hill were analysed via LIDAR resulting in the below:

86.779m at SH 31635 38073 (new summit position)

85.355m at SH 31355 38373 (position of 86m spot height and old listed summit)

The summit height produced by LIDAR analysis is 86.8m and is positioned at SH 31635 38073, this position is not given a spot height on contemporary Ordnance Survey maps although it does possess an uppermost 85m ring contour on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website, whilst OS Maps show an 85m uppermost ring contour at the position of the LIDAR summit and an uppermost 80m ring contour at the position of the old summit, which is a more accurate representation of the height of this hill.  Therefore, the new summit position for this hill is approximately 350 metres south-eastward from the previously listed position.

LIDAR image of Cae Benglog

The full details for the hill are:

Group:  Pen Llŷn

Summit Height:  86.8m (LIDAR)

Name:  Cae Benglog

OS 1:50,000 map:  123

Summit Grid Reference (New Position):  SH 31635 38073 (LIDAR)  

Drop:  20.9m (LIDAR)

Myrddyn Phillips (April 2018)






Mapping Mountains - Summit Relocations - 30-99m Twmpau

Allt Fawr (SH 383 356) - 6th summit relocation

Hill Reclassifications post for Allt Fawr

Significant Height Revisions post for Allt Fawr

There has been a Summit Relocation to a hill that is now listed in the 30-99m Twmpau, with the summit height and its position, drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

The criteria for this list are:

30-99m Twmpau – Welsh hills at and above 30m and below 100m in height that have a minimum 30m of drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at and above 30m and below 100m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The name of the hill is Allt Fawr and it is adjoined to the Pen Llŷn range of hills, which is situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the A 499 road to its west and the A 497 road to its east, and has the town of Pwllheli towards its south-west.

As the hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so the proximity of the roads will give relatively easy access.

Prior to LIDAR analysis this hill was listed with c 18m of drop based on an estimated c 46m summit height with the hill given three uppermost 45m ring contours on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website, and an estimated bwlch height of c 28m based on bwlch contouring at 5m intervals and between 25m – 30m on this same map.

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website

Extract from OS Maps

The position of the three uppermost 45m ring contours were analysed via LIDAR with a fourth point also examined resulting in the below:

48.889m at SH 38347 35695 (new summit position)

46.569m at SH 38145 35521 (c 46m old listed summit)

44.962m at SH 38406 35898

44.944m at SH 38383 35833

The summit height produced by LIDAR analysis is 48.9m and is positioned at SH 38347 35695, this position is not given a spot height or an uppermost 45m ring contour on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website, but is given a 45m ring contour on OS Maps (the recent replacement for OS Get-a-map).  The new summit position for this hill is approximately 250 metres north-eastward from the previously listed summit position.

LIDAR image of Allt Fawr

The full details for the hill are:

Group:  Pen Llŷn

Summit Height:  48.9m (LIDAR)

Name:  Allt Fawr

OS 1:50,000 map:  123

Summit Grid Reference (New Position):  SH 38347 35695 (LIDAR)  

Drop:  23.1m (LIDAR)

Myrddyn Phillips (April 2018)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Pt. 47.8m (SH 604 438) - 5th summit relocation

There has been a Summit Relocation to a hill that now appears in the list of 30-99m Twmpau, with the hill’s height and drop confirmed by analysis conducted by Aled Williams of data produced via LIDAR.  With the title of Twmpau being an acronym for thirty welsh metre prominences and upward.

Accompanying each 100m height band within the Twmpau list is a sub list entitled Sub-Twmpau, the criteria for the height band of 30-99m Twmapu are:

30-99m Twmpau – All Welsh hills at and above 30m and below 100m in height that have a minimum 30m of drop.

30-99m Sub-Twmpau – All Welsh hills at and above 30m and below 100m in height with 20m or more and below 30m of drop.

As I do not know a separate and independent name for this hill it is being listed by the point (Pt. 47.8m) notation, and it is situated in the Moelwynion range of hills and is placed in the Region of North Wales (Region A, Sub-Region A1).  The hill is positioned with the Welsh Highland Railway and the A 498 road to its west and the A 4085 road to its east, and has the village of Beddgelert to its north north-west and the town of Porthmadog towards its south-west.

As the hill is not a part of designated open access land permission to visit should be sought, however the hill has a well-used path leading through the deciduous wood that takes in its summit indicating that people have visited this area for many years.

Prior to analysis of data produced via LIDAR this hill was not listed in the Hills to be surveyed sub list that accompanied the Welsh P30 lists published on Geoff Crowder’s v-g.me website.  When these lists were re-evaluated after they were standardised and also drop values added, this hill was listed with c 20m of drop based on the 46m summit spot height positioned at SH 60384 43736 that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 26m based on 10m contour intervals between 20m – 30m.  However, since these lists were re-evaluated OS Maps (the recent replacement for OS Get-a-map) are now available and show 5m contour intervals with the uppermost 45m contour ring matching the location of where LIDAR gives the 47.8m summit.  

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website indicating the position of the LIDAR summit in relation to where the 46m spot height appears

The uppermost 45m ring contour shown on the OS Maps website

The summit height produced by data via LIDAR is 47.8m and is positioned at SH 60404 43809, this position is not given a spot height on Ordnance Survey maps and is approximately 80 metres northward from the previously listed summit position.

The full details for the hill are:

Group:  Moelwynion

Summit Height:  47.8m (data via LIDAR)

Name:  Pt. 47.8m

OS 1:50,000 map:  124

Summit Grid Reference (New Position):  SH 60404 43809 

  

Drop:  23.8m (data via LIDAR)

My thanks to Aled Williams for sending the details of this hill to me

Myrddyn Phillips (February 2018)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Bryn y Bont (SH 596 459) - 4th summit relocation

Hill Reclassifications post for Bryn y Bont

Significant Height Revisions post for Bryn y Bont

There has been a Summit Relocation to a hill that now appears in the Double Sub-Twmpau list that accompanies the 30-99m Twmpau list, with the hill’s height and drop confirmed by analysis by Aled Williams of data produced by LIDAR.  With the title of Twmpau being an acronym for thirty welsh metre prominences and upward.

Accompanying each 100m height band within the main Twmpau list is a sub list entitled the Sub-Twmpau, with the Double Sub-Twmpau attached to the lower tier height band of Welsh hills.

The criteria for the lower tier of Twmpau hills are:

30-99m Twmpau – All Welsh hills at and above 30m and below 100m in height with 30m minimum drop.

30-99m Sub-Twmpau – All Welsh hills at and above 30m and below 100m in height with 20m or more and below 30m of drop.

Double Sub-Twmpau – All Welsh hills at and above 20m and below 30m in height with 20m or more and below 30m of drop.

The name of the hill is Bryn y Bont and it is situated in the Moelwynion range of hills and is placed in the Region of North Wales (Region A, Sub-Region A1).  The hill is positioned with the A 4085 road to its north and its east and the A 498 road to its west, and has the Afon Glaslyn also to its immediate west, with the hamlet of Nantmor positioned to the east of the hill and the village of Beddgelert towards its north.

As the hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so an ascent from the convenience of the road to its north or east is likely to be the easiest.

Prior to analysis of data produced via LIDAR this hill was not listed in the Hills to be surveyed sub list that accompanied the Welsh P30 lists published on Geoff Crowder’s v-g.me website.  When these lists were re-evaluated after they were standardised and also drop values added, this hill was listed with c 16m of drop based on an estimated c 20m summit height positioned at SH 59600 46035 which was based on this hill’s small uppermost 20m ring contour on Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and an estimated bwlch height of c 4m based on bwlch contouring at 10m intervals and between 0 – 10m, with the caveat that the 4m spot height positioned at SH 59756 45814 and shown on the Ordnance Survey 1:25,000 Explorer map is probably not at the position of the critical bwlch.  However, since these lists were re-evaluated OS Maps (the recent replacement for OS Get-a-map) are now available and show 5m contour intervals with an uppermost 25m ring contour for this hill. 

Extract from the Ordnance Survey 1:25,000 Explorer map

Extract from the Ordnance Survey Interactive Coverage map hosted on the Geograph website indicating the position of the LIDAR summit in relation to the uppermost 20m ring contour

The uppermost 25m ring contour shown on the OS Maps website

The summit height produced by data via LIDAR is 25.2m and is positioned at SH 59641 45973, this position is not given a spot height on Ordnance Survey maps and is outside of the uppermost 20m ring contour on the 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 70 metres south-eastward from the previously listed summit position.

The full details for the hill are:

Group:  Moelwynion

Summit Height:  25.2m (data via LIDAR)

Name:  Bryn y Bont

OS 1:50,000 map:  115

Summit Grid Reference (New Position):  SH 59641 45973

  

Drop:  20.9m (data via LIDAR)

My thanks to Aled Williams for sending the details of this hill to me

Myrddyn Phillips (February 2018)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Bryn y Gwynt (SH 599 449) - 3rd summit relocation

Hill Reclassifications post for Bryn y Gwynt

Significant Name Changes post for Bryn y Gwynt

Significant Height Revisions post for Bryn y Gwynt

There has been a Summit Relocation to a hill that is now listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height, their locations, the drop, dominance and status of the hill confirmed by LIDAR analysis conducted by Aled Williams and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams.

LIDAR image of Bryn y Gwynt (SH 599 449)

The criteria for the two listings that this summit relocation applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format.

The name the hill is listed by is Bryn y Gwynt and this was derived from local enquiry and the series of Ordnance Survey Six-Inch maps and it is situated in the Moelwynion range of hills in the Region of North Wales (Region A, Sub-Region A1), and is positioned with the A 4085 road to its north-east and has the Welsh Highland Railway to its immediate west and overlooks the Afon Glaslyn also to its west, and has the village of Beddgelert to its north north-west and the town of Porthmadog to its south south-west.

The hill is a part of Coed Hafod y Llyn, and as this name implies its summit is placed in woodland which is deciduous, and as the summit is not a part of designated open access land permission to visit should be sought, however paths are indicated on the map to the north, east and south of this hill’s summit and therefore gaining access to its lower slopes has probably been accepted for many years.

Prior to LIDAR analysis this hill was listed in the Hills to be surveyed sub list that accompanied the Welsh P30 lists published on Geoff Crowder’s v-g.me website.  When these sub lists were standardised and also drop values added, this hill was listed with an estimated c 29m of drop based on the 56m spot height that appears on the Ordnance Survey 1:25,000 Explorer map at SH 59881 44828 and an estimated bwlch height of c 27m based on contouring at 10m intervals between 20m – 30m, with the caveat that the 27m spot height that appears on a road at SH 60168 45293 on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website is judged not to be positioned at the critical bwlch.

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website

LIDAR analysis confirms this hill to be a 30-99m Twmpau and a Dominant hill, but as the summit has now been surveyed with the Trimble GeoXH 6000, it is this result that is being prioritised for listing purposes.

The Trimble GeoXH 6000 gathering data at the summit of Bryn y Gwynt

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 59.9m and this is positioned at SH 59949 44919, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 80 metres north-eastward from where the previously listed summit position.

The full details for the hill are:

Group:  Moelwynion

Name:  Bryn y Gwynt

OS 1:50,000 map:  124

Summit Height:  59.9m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference (New Position):  SH 59949 44919 (Trimble GeoXH 6000) 

  

Bwlch Height:  28.0m (LIDAR)

Bwlch Grid Reference:  SH 60224 45248 & SH 60226 45258 & SH 60227 45259 (LIDAR)

Drop:  31.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  53.21% (Trimble GeoXH 6000 summit and LIDAR bwlch)  

My thanks to Aled Williams for sending the details of this hill to me

Myrddyn Phillips (February 2018)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Bryn Tŵr (SH 604 441) - 2nd summit relocation

Survey post for Bryn Tŵr

Significant Height Revisions post for Bryn Tŵr

There has been a Summit Relocation to a hill listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales which was initiated by a survey with the Trimble GeoXH 6000 which took place on the 23^rd December 2017 in wet conditions but with clear visibility.

The criteria for the two lists this height revision affects are:

30-99m Twmpau – Welsh hills at and above 30m and below 100m in height that have 30m minimum drop.  With the word Twmpau being an acronym standing for ‘thirty welsh metre prominences and upward’.

Y Trechol – The Dominant Hills of Wales - Welsh P30s whose prominence equal or exceed half that of their absolute height.

The name of the hill is Bryn Tŵr and it is placed in the Moelwynion range of hills which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and the hill is positioned overlooking the A 4085 road and the Nanmor to its east, with it being positioned between the village of Beddgelert to its north north-west and Porthmadog to its south south-west. 

Bryn Tŵr (SH 60453 44187)

As the summit of the hill is not on designated open access land permission to visit should be sought, however the hill has a well-used path leading to its summit indicating that people have visited this hill for many years.

The hill’s summit position was previously given as SH 60493 44178, this is where the 52m spot height appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.  This spot height appears in an uppermost 50m ring contour, whilst the position of the 54.5m (converted to OSGM15) summit is outside of this ring contour which is probably due to the cartographer having difficulty with the tree cover.

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website

Therefore, the position of the relocated summit is at SH 60453 44187 and is ground at the base of a slate chair dedicated to Rhys Goch; a 15^th century bard who lived at Hafod Garegog, near Beddgelert.  This position is within the 40m ring contour shown on Ordnance Survey maps and no spot height is given to it, the relocated summit is approximately 50 metres east from where the previously listed summit is positioned.

The full details for the hill are:

Group:  Moelwynion

Summit Height:  54.5m (converted to OSGM15)

Name:  Bryn Tŵr

OS 1:50,000 map:  124

Summit Grid Reference (New Position):  SH 60453 44187

Drop:  c 43m

Dominance:  77.99%

The Trimble GeoXH 6000 gathering data at the summit of Bryn Tŵr

For details on the survey that confirmed the summit relocation of this hill

Myrddyn Phillips (January 2018)

Mapping Mountains - Summit Relocations - 30-99m Twmpau

Graig Wen (SH 397 947) - 1st summit relocation 

Survey post for Graig Wen


There has been a Summit Relocation to the listing of 30-99m Twmpau (thirty welsh metre prominences and upward), with the hill also listed in Y Trechol - The Dominant Hills of Wales.  This is the first post under this heading and the summit relocation was initiated by a survey with the Trimble GeoXH 6000 with the following details being retrospective as the Trimble survey that resulted in this summit relocation was conducted on 7^th September 2014.

The survey was conducted in the north of Ynys Môn on a fine and bright day on a grouping of three excellent hills in the company of Alex Cameron, with the hill situated north-eastward of the small town of Cemaes, with the nearest major road to the hill being the A 5025 which is 1km directly south of its summit.

The name of the hill is Graig Wen, and its summit position used to be listed beside its trig pillar on a small rock outcrop at SH 398 947 which is within a small continuous 90m ring contour on current Ordnance Survey maps.

Its new summit position is approximately 80 metres westward from its trig pillar and is the top of a large boulder which is prominent when approaching the hill from the west.  This position has no uppermost 90m ring contour given it on current Ordnance Survey maps.

The full details for the hill are:

Cardinal Hill:  Mynydd Twr

Summit Height:  91.3m (converted to OSGM15, Trimble GeoXH 6000)

Name:  Graig Wen

OS 1:50,000 map:  114

Summit Grid Reference (New Position):  SH 39734 94739 (Trimble GeoXH 6000) 

  

Drop:  49.6m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  54.33% (Trimble GeoXH 6000 summit and LIDAR bwlch)

The Trimble GeoXH 6000 gathering data at the new summit position of Graig Wen, with the old position for the summit next to the hill's trig pillar in the background on the left of the photo

For details on the survey that relocated the summit of this hill please click {here}

Myrddyn Phillips (September 2014)