100m Twmpau – Summit Relocations

 

100m Twmpau – Summit Relocations

The 100m Twmpau (an acronym for thirty welsh metre prominences and upward) are the Welsh hills at or above 100m and below 200m in height that have a minimum drop of 30m.  Accompanying the main P30 list is a sub list entitled the 100m Sub-Twmpau with the qualification to this sub category being all Welsh hills at or above 100m and below 200m 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 list appear below presented chronologically in receding order.

Mapping Mountains - Summit Relocations - 100m Twmpau

Graig y Barcut (SN 546 027) - 56th summit relocation

Hill Reclassifications post for Graig y Barcut

Significant Name Changes post for Graig y Barcut

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Graig y Barcut (SN 546 027)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Graig y Barcut and this was derived 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, west and east, and the A4138 road to its south, and has the town of Pontarddulais towards the east.

When the original 100m 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, as it was considered not to meet the criteria then used for the main P30 list.

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 32m of drop, based on the 104m summit spot height positioned at SN 54707 02798 that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 72m bwlch height, based on interpolation of 5m contouring between 70m – 75m. 

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 105.3m positioned at SN 54698 02765.  However, this is to the top 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 Graig y Barcut (SN 546 027)

The height produced by LIDAR analysis to the highest remaining natural ground of this hill is 104.0m and is positioned at SN 54698 02770, 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 of this hill is 104.0m and is positioned at SN 54698 02770, this is relatively close to where the spot height appears on the Ordnance Survey 1:25,000 Explorer map, and is approximately 5 metres northward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Graig y Barcut 

OS 1:50,000 map:  159

Summit Height:  104.0m (LIDAR) 

Summit Grid Reference (New Position):  SN 54698 02770 (LIDAR) 

Bwlch Height:  71.8m (LIDAR) 

Bwlch Grid Reference:  SN 54693 03117 (LIDAR) 

Drop:  32.2m (LIDAR) 

 

Myrddyn Phillips (November 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Pt. 120.4m (SN 507 022) - 55th summit relocation

Significant Name Changes post for Pt. 120.4m

 

There has been a Summit Relocation to a hill that is listed in the 100m 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. 120.4m (SN 507 022)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m Twmpau by Myrddyn Phillips

The hill is being listed by the point (Pt. 120.4m) notation 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 a minor road to its east and north, the B4309 road to its west and the A476 road to its south, and has the town of Llanelli towards the south.

When the original 100m 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 with a none interpolated 120c summit height, based on the uppermost contour that appears at SN 50750 02281 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-assessed and it was listed with an estimated c 24m of drop, based on an estimated c 121m summit height and an estimated c 97m bwlch height, with both heights based on interpolation of 5m contouring. 

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 121.7m positioned at SN 50761 02286.  However, this is to the top 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 Pt. 120.4m (SN 507 022)

The height produced by LIDAR analysis to the natural summit of this hill is 120.4m and is positioned at SN 50743 02266 and SN 50741 02271 and SN 50744 02273 and SN 50753 02271, 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 120.4m and is positioned at SN 50743 02266 and SN 50741 02271 and SN 50744 02273 and SN 50753 02271, this is relatively close to where the interpoated summit position was given, and is approximately 20 metres south-westward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Pt. 120.4m 

OS 1:50,000 map:  159

Summit Height:  120.4m (LIDAR)               

Summit Grid Reference (New Position):  SN 50743 02266 & SN 50741 02271 & SN 50744 02273 & SN 50753 02271 (LIDAR) 

Bwlch Height:  98.1m (LIDAR) 

Bwlch Grid Reference:  SN 51034 02544 (LIDAR) 

Drop:  22.3m (LIDAR) 

 

Myrddyn Phillips (October 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Pt. 162.1m (SN 508 034) - 54th summit relocation

Significant Name Changes post for Pt. 162.1m

 

There has been a Summit Relocation to a hill that is listed in the 100m 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. 162.1n (SN 508 034)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m Twmpau by Myrddyn Phillips

The hill is being listed by the point (Pt. 162.1m) notation 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 a minor road and the B4309 road to its west and a minor road and the A476 road to its east, and has the town of Llanelli towards the south.

When the original 100m 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 with a 161m summit height, based on the spot height positioned on a minor road that appears at SN 50822 03406 on the contemporary Ordnance Survey 1:50,000 Landranger and 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-assessed and it was listed with 23m of drop, based on the 161m summit spot height and the 138m 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 102.6m positioned at SN 50798 03441.  However, this is to the top 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 Pt. 162.1m (SN 508 034)

The height produced by LIDAR analysis to the natural summit of this hill is 162.1m and is positioned at SN 50860 03434 and SN 50868 03434, 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 162.1m and is positioned at SN 50860 03434 and SN 50868 03434, 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 62 metres eastward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Pt. 162.1m 

OS 1:50,000 map:  159

Summit Height:  162.1m (LIDAR) 

Summit Grid Reference (New Position):  SN 50860 03434 & SN 50868 03434 (LIDAR) 

Bwlch Height:  138.2m (LIDAR) 

Bwlch Grid Reference:  SN 50307 03907 (LIDAR) 

Drop:  23.9m (LIDAR) 

 

Myrddyn Phillips (September 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Pant y Brwynog (SN 548 037) - 53rd summit relocation

Hill Reclassifications post for Pant y Brwynog

Significant Height Revisions post for Pant y Brwynog

Significant Name Changes post for Pant y Brwynog

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Pant y Brwynog (SN 548 037)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Pant y Brwynog and this was derived 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-east, west and south, and the A476 road farther to its west, the A4138 road to its south-east and the M4 motorway farther to its east, and has the town of Pontarddulais towards the east.

When the original 100m 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-assessed and it was listed with an estimated c 27m of drop, based on the 130m summit spot height positioned at SN 54868 03726 that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and an estimated c 103m bwlch height, based on interpolation of 5m contouring between 100m – 105m. 

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 128.0m positioned at SN 54878 03729.  However, this is to the top 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 Pant y Brwynog (SN 548 037)

The height produced by LIDAR analysis to the natural summit of this hill is 127.65m and is positioned at SN 54886 03732, 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 127.65m and is positioned at SN 54886 03732, 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 8 metres eastward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Pant y Brwynog 

OS 1:50,000 map:  159

Summit Height:  127.65m (LIDAR) 

Summit Grid Reference (New Position):  SN 54886 03732 (LIDAR) 

Bwlch Height:  102.6m (LIDAR) 

Bwlch Grid Reference:  SN 54795 03991 (LIDAR) 

Drop:  25.0m (LIDAR) 

 

Myrddyn Phillips (August 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Cae Gwar Allt (SN 455 133) - 52nd summit relocation

Significant Name Changes post for Cae Gwar Allt

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Cae Gwar Allt (SN 455 133)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m 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 Cae Gwar Allt and this was derived 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, west and south-east, and has the A4306 road farther to its north-east and the A4309 road to its south-west, and has the town of Caerfyrddin (Carmarthen) towards the north-west.

When the original 100m 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 111m summit height, based on the spot height that appears at SN 45492 13327 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-assessed and it was listed with an estimated c 44m of drop, based on the 111m summit spot height and an estimated c 67m bwlch height, based on interpolation of 5m contouring between 65m – 70m.  With these values giving this hill 39.64% dominance. 

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 109.8m positioned at SN 45495 13312.  However, this is probably excavated ground from construction of a pool 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 Gwar Allt (SN 455 133)

The height produced by LIDAR analysis to the natural summit of this hill is 109.7m and is positioned at SN 45512 13322, 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 109.7m and is positioned at SN 45512 13322, this position is relatively close to where the spot height appears on the contemporary Ordnance Survey 1:25,000 Explorer map, and is approximately 17 metres north-eastward from the high point of the excavated ground. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Cae Gwar Allt 

OS 1:50,000 map:  159

Summit Height:  109.7m (LIDAR) 

Summit Grid Reference (New Position):  SN 45512 13322 (LIDAR) 

Bwlch Height:  67.5m (LIDAR) 

Bwlch Grid Reference:  SN 46302 13388 (LIDAR) 

Drop:  42.2m (LIDAR) 

Dominance:  38.46% (LIDAR) 

 

Myrddyn Phillips (July 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Safle Claddu Nant y Caws (SN 468 174) & (SN 469 174) and Cae Mawr (SN 462 175) - 51st summit relocation

Hill Reclassifications post for Safle Claddu Nant y Caws and Cae Mawr

Significant Height Revisions post for Safle Claddu Nant y Caws and Cae Mawr

 

There has been confirmation of a Summit Relocation to a hill that is now listed as a Dual Summit in the 100m 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 Cae Mawr (SN 462 175) and Safle Claddu Nant y Caws (SN 468 174) & (SN 469 174)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m 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

Dual Summit hills:

A hill classified as a Dual Summit is defined as one which has an extant natural summit coupled with that of a higher artificial summit, with the latter that can be described as stable in character.  In the main, these recent man-made constructions are the result of quarrying activities producing spoil tips, or as in this instance a landfill.  These recent man-made constructions are treated differently to ancient man-made constructions such as hill forts and tumuli, as if the latter are deemed stable and of an earthen character their age dictates that they can be viewed as being permanent in nature and are now effectively a part of the hill.  For those bagging Dual Summit hills, a visit to either the natural high point or the elevated man-made high point is sufficient to claim an ascent of the hill.  With the Dual Summit classification being a relatively new category and fist instigated in January 2018 for a Dual Summit Pedwar. 

The name the hill is now listed by is Safle Claddu Nant y Caws for the higher man-made summit and Cae Mawr for the lower natural summit, 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 the two summits are positioned with the A48 road to their north and a minor road to their south-west, and has the town of Caerfyrddin (Carmarthen) towards the north-west. 

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, the natural summit was included in the main P30 list with a 155m summit height, based on the spot height adjoined to a triangulation pillar positioned at SN 46405 17608 that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

Extract from the 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 then separated in to its two component parts, with the man-made summit listed with an estimated c 59m of drop, based on an estimated c 156m summit height positioned at SN 46909 17343 and an estimated c 97m bwlch height, with both heights based on interpolation of 5m contouring that appeared on the interactive mapping hosted on the OS Maps website.  With the lower natural summit listed with a 155 summit height and the bwlch between these two summits estimated as c 138m, which if separating these hills would give an estimated c 17m of drop.

However, it was not until LIDAR became available that the details for these summits 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 Cae Mawr (SN 462 175) and Safle Claddu Nant y Caws (SN 468 174) & (SN 469 174)

LIDAR analysis gives the highest ground at the man-made summit as 163.8m positioned at SN 46899 17416 & SN 46900 17411, and this compared to the originally listed summit which LIDAR gives as 155.1m positioned at SN 46268 17566 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 higher of the two Dual Summits is 163.8m and is positioned at SN 46899 17416 & SN 46900 17411, and this for listing purposes is the prioritised summit and it is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 630 metres east south-eastward from where the originally listed summit is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Sylen

Name:  Safle Claddu Nant y Caws (artificial Dual Summit) and Cae Mawr (natural Dual Summit)

OS 1:50,000 map:  159

Summit Height:  163.8m (artificial Dual Summit) and 155.1m (natural Dual Summit) (LIDAR)

Summit Grid Reference (New Position):  SN 46899 17416 & SN 46900 17411 (artificial Dual Summit) and SN 46268 17566 (natural Dual Summit) (LIDAR)

Bwlch Height:  98.5m (LIDAR)

Bwlch Grid Reference:  SN 39491 11374 & SN 39493 11375 (LIDAR)

Drop:  65.3m (artificial Dual Summit) and 56.6m (natural Dual Summit) (LIDAR)

Dominance:  39.89% (artificial Dual Summit) and 36.50% (natural Dual Summit) (LIDAR)

 

Myrddyn Phillips (July 2024)

 

Mapping Mountains - Summit Relocations - 100m Twmpau

Bryn y Beudy (SH 507 404) - 50th summit relocation

Hill Reclassifications post for Bryn y Beudy

Significant Name Changes post for Bryn y Beudy

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Bryn y Beudy (SH 507 404)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Bryn y Beudy 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 minor roads to its north and south, the B4411 road to its south-west and the A487 road to its north-east, and has the town of Cricieth towards the south.

When the original 100m 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-assessed and it was listed with 22m of drop, based on the 156m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and which is positioned at SH 50788 40454 and the 134m 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 155.4m positioned at SH 50797 40464 and SH 50801 40464.  However, this is to the top 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 Bryn y Beudy (SH 507 404)

The height produced by LIDAR analysis to the natural summit of this hill is 155.2m and is positioned at SH 50785 40428 and SH 50786 40429, 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 155.2m and is positioned at SH 50785 40428 and SH 50786 40429, this position is relatively close to where the spot height appears on the contemporary Ordnance Survey 1:25,000 Explorer map, and is approximately 36 metres south-westward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Moel Hebog 

Name:  Bryn y Beudy 

OS 1:50,000 map:  124

Summit Height:  155.2m (LIDAR) 

Summit Grid Reference (New Position):  SH 50785 40428 & SH 50786 40429 (LIDAR) 

Bwlch Height:  132.7m (LIDAR) 

Bwlch Grid Reference:  SH 51229 40222 (LIDAR) 

Drop:  22.5m (LIDAR) 

 

Myrddyn Phillips (May 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Coed Gaer (SH 799 808) - 49th summit relocation

Survey post for Coed Gaer

Significant Name Changes post for Coed Gaer

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis conducted by Myrddyn Phillips. 

Coed Gaer (SH 799 808)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m 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 Coed Gaer, and it is adjoined to the Mynydd Hiraethog group of hills, which are situated in the northern part of North Wales (Region A, Sub-Region A2), and it is positioned with the B5115 road to its north, the A470 road to its west and minor roads to its south and east, and has the town of Llandudno towards the north-west. 

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

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a non-interpolated c 130m summit height, with the prioritised summit position given as SH 802 810, and with an accompanying note stating; Two points of same height – other at SH799808. 

The Trimble GeoXH 6000 gathering data at the summit of Coed Gaer

However, it was not until the survey with the Trimble GeoXH 6000 that an accurate height could be ascertained for one of these points and not until LIDAR became available that the details for these two points could be 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 Coed Gaer (SH 799 808)

LIDAR analysis gives the highest ground close to the old prioritised summit as 131.1m positioned at SH 80216 80952, whilst the survey with the Trimble GeoXH 6000 gives the height of the recognised summit as 134.0m positioned at SH 79924 80840, 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 the Trimble GeoXH 6000 survey to the recognised summit is 134.0m and is positioned at SH 79924 80840, this position is given an uppermost 130m ring contour on the contemporary Ordnance Survey 1:25,000 Explorer map, and is approximately 290 metres south-westward from the position of the old prioritised summit. 

 

The full details for the hill are: 

Group:  Mynydd Hiraethog 

Name:  Coed Gaer 

OS 1:50,000 map:  115

Summit Height:  134.0m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference (New Position):  SH 79924 80840 (Trimble GeoXH 6000) 

Bwlch Height:  60.0m (LIDAR) 

Bwlch Grid Reference:  SH 81486 81889 (LIDAR) 

Drop:  74.0m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

Dominance:  55.25% (Trimble GeoXH 6000 summit and LIDAR bwlch) 

 

Myrddyn Phillips (April 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Bryn Pydew (SH 810 789) - 48th summit relocation

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Bryn Pydew (SH 810 789)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m 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 Bryn Pydew, and it is adjoined to the Mynydd Hiraethog group of hills, which are situated in the northern part of North Wales (Region A, Sub-Region A2), and it is positioned with the A470 road to its west, a minor road to its immediate south and the A55 road to its south-east, and has the town of Llandudno towards the north-west. 

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

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a 128m summit height, based on the spot height positioned at SH 81095 79015 which appears on the contemporary Ordnance Survey 1:50,000 Landranger map. 

Extract from the Ordnance Survey 1:50,000 Landranger 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 130.0m positioned at SH 81103 78989.  However, this is to the top of a covered reservoir 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 Bryn Pydew (SH 810 789)

The height produced by LIDAR analysis to the natural summit of this hill is 128.5m and is positioned at SH 81097 78986, 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 128.5m and is positioned at SH 81097 78986, this position is relatively close to where the spot height appears on the contemporary Ordnance Survey 1:50,000 Landranger map, and is approximately 6 metres south-westward from the high point of the covered reservoir. 

 

The full details for the hill are: 

Group:  Mynydd Hiraethog 

Name:  Bryn Pydew 

OS 1:50,000 map:  116

Summit Height:  128.5m (LIDAR) 

Summit Grid Reference (New Position):  SH 81097 78986 (LIDAR) 

Bwlch Height:  13.15m (LIDAR) 

Bwlch Grid Reference:  SH 80308 80155 (LIDAR) 

Drop:  115.4m (LIDAR) 

Dominance:  89.77% (LIDAR) 

 

Myrddyn Phillips (April 2024)

  

Mapping Mountains - Summit Relocations - 100m Twmpau

Lan Fach (SN 630 267) - 47th summit relocation

Hill Reclassifications post for Lan Fach

Significant Name Changes post for Lan Fach

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Lan Fach (SN 630 267)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Lan Fach 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 with minor roads to its north, west, south and east, the A40 road farther to its south and the B4302 road farther to its east, and has the town of Llandeilo towards the south.

When the original 100m 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-assessed and it was listed with an estimated c 20m of drop, based on an estimated c 181m summit height positioned at SN 631 267 and an estimated c 161m bwlch height, with both heights based on interpolation of 10m contouring that appear 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 183.3m positioned at SN 63094 26744.  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 Lan Fach (SN 630 267)

The height produced by LIDAR analysis to the highest remaining natural ground of this hill is 182.6m and is positioned at SN 63091 26746, 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 of this hill is 182.6m and is positioned at SN 63091 26746, 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 9 metres north-westward from where the previously estimated summit position was given and approximately 3 metres north-westward from where the high point of the raised field boundary is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Mallaen 

Name:  Lan Fach 

OS 1:50,000 map:  146

Summit Height:  182.6m (LIDAR) 

Summit Grid Reference (New Position):  SN 63091 26746 (LIDAR) 

Bwlch Height:  159.1m (LIDAR) 

Bwlch Grid Reference:  SN 62212 26133 (LIDAR) 

Drop:  23.4m (LIDAR) 

 

Myrddyn Phillips (March 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Crug Cwm (SN 612 257) - 46th summit reloocation

Significant Name Changes post for Crug Cwm

 

There has been a Summit Relocation to a hill that is listed in the 100m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from 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 Crug Cwm (SN 612 257)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Craig Cwm 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 the B4302 road farther to its east, and has the town of Llandeilo towards the south south-east.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a non-interpolated c 190m summit height positioned at SN 61434 26099, based on the largest of four uppermost 190m ring contours which appears on the contemporary Ordnance Survey 1:25,000 Explorer map. 

Extract from the 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 34m of drop, based on an estimated c 193m summit height positioned at SN 61434 26099, with the next largest 190m ring contour estimated as c 192m positioned at SN 61257 25745, and an estimated c 159m bwlch height, based on interpolation of 10m contouring between 150m – 160m.

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 Crug Cwm (SN 612 257)

LIDAR analysis gives the highest ground on this hill as 192.8m positioned at SN 61260 25753, as opposed to 191.4m to the previously listed summit positioned at SN 61430 26107 and SN 61432 26105, 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 summit of this hill is 192.8m and is positioned at SN 61260 25753, 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 350 metres south-westward from where the previously listed summit is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Mallaen 

Name:  Crug Cwm 

OS 1:50,000 map:  146

Summit Height:  192.8m (LIDAR) 

Summit Grid Reference (New Position):  SN 61260 25753 (LIDAR) 

Bwlch Height:  159.0m (LIDAR) 

Bwlch Grid Reference:  SN 63103 27207 (LIDAR) 

Drop:  33.8m (LIDAR) 

 

Myrddyn Phillips (February 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Cwm y Rhidyll (SN 625 249) - 45th summit relocation

Significant Name Changes post for Cwm y Rhidyll

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Cwm y Rhidyll (SN 625 249)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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. 

100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Cwm y Rhidyll 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 with minor roads to its north-east, north-west and south, and the A40 road farther to its south and the B4302 road to its east, and has the town of Llandeilo towards the south.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a 157m summit height, based on the spot height positioned at SN 62592 24875 which 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 157.1m positioned at SN 62593 24935.  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 Cwm y Rhidyll (SN 625 249)

The height produced by LIDAR analysis to the natural summit of this hill is 156.6m and is positioned at SN 62543 24916, 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 156.6m and is positioned at SN 62543 24916, 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 50 metres north-westward from where the 157m spot height is positioned and approximately 50 metres west south-westward from where the high point of the raised field boundary is positioned.

 

The full details for the hill are: 

Group:  Mynydd Mallaen 

Name:  Cwm y Rhidyll 

OS 1:50,000 map:  159

Summit Height:  156.6m (LIDAR) 

Summit Grid Reference (New Position):  SN 62543 24916 (LIDAR) 

Bwlch Height:  113.7m (LIDAR) 

Bwlch Grid Reference:  SN 62913 25209 (LIDAR) 

Drop:  42.9m (LIDAR) 

 

Myrddyn Phillips (February 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Coed Uchaf (SJ 232 683) - 44th summit relocation

Hill Reclassifications post for Coed Uchaf

Significant Height Revisions post for Coed Uchaf

Significant Name Changes post for Coed Uchaf

 

There has been a Summit Relocation to a hill that is listed in the 100m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from 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 Coed Uchaf (SJ 232 683)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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 100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Coed Uchaf, and it is adjoined to the Moel y Gamelin group of hills, which are situated in the north-eastern part of North Wales (Region A, Sub-Region A2), and it is positioned encircled by minor roads, with the A55 road farther to its north, the B5123 road farther to its west, the A541 road farther to its south and the A5119 road farther to its east, and has the town of Y Fflint (Flint) towards the north.

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed with a summit height of c 160m positioned at SJ 232 686, based on the uppermost non-interpolated ring contour that appears on the contemporary Ordnance Survey 1:25,000 Explorer map. 

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

Since the original publication of the Welsh P30 lists on Geoff Crowder’s v-g.me website there have been a number of maps made available online.  Some of these are historic such as the series of Six-Inch maps on the National Library of Scotland website.  Whilst others were digitally updated such as the Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map, whilst others are current and digitally updated such as the interactive mapping on the Magic Maps and WalkLakes websites.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated against the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.  This mapping had many spot heights not on other publicly available maps and for this hill it had a 162m summit spot height positioned at SJ 23209 68591. 

LIDAR image of the old summit position at SJ 23205 68597

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 image of the new Coed Uchaf summit position at SJ 23205 68344

The height produced by LIDAR analysis to the summit of this hill is 161.7m positioned at SJ 23205 68344, as opposed to the old listed summit which LIDAR gives as 160.5m positioned at SJ 23205 68597, 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 summit height produced by LIDAR analysis is 161.7m and this is positioned at SJ 23205 68344, 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 feature; a wood as opposed to an open field and is approximately 253 metres southward from where the originally listed summit is positioned. 

 

The full details for the hill are:

Group:  Moel y Gamelin 

Name:  Coed Uchaf 

OS 1:50,000 map:  117

Summit Height:  161.7m (LIDAR) 

Summit Grid Reference (New Position):  SJ 23205 68344 (LIDAR) 

Bwlch Height:  132.6m (LIDAR) 

Bwlch Grid Reference:  SJ 23101 68383 (LIDAR) 

Drop:  29.1m (LIDAR) 

 

Myrddyn Phillips (February 2024)

Mapping Mountains - Summit Relocations - 100m Twmpau

Blacksmith’s Park (SN 219 182) - 43rd summit relocation

Significant Name Changes post for Blacksmith's Park

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Blacksmith's Park (SN 219 182)

The criteria for the two listings that this summit relocation applies to are:100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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 100m 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 Blacksmith’s Park 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 north-west and north-east, and the A40 road to its south, and has the town of Hendy-gwyn ar Daf (Whitland) towards the south-west.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a 151m summit height, based on the spot height positioned at SN 21932 18252 which 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 150.1m positioned at SN 21968 18273.  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 Blacksmith's Park (SN 219 182)

The height produced by LIDAR analysis to the natural summit of this hill is 150.05m and is positioned at SN 21949 18280, 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 150.05m and is positioned at SN 21949 18280, 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 north-eastward from where the 151m spot height is positioned and approximately 30 metres north-westward from where the high point of the raised field boundary is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Preseli 

Name:  Blacksmith’s Park 

OS 1:50,000 map:  158

Summit Height:  150.05m (LIDAR) 

Summit Grid Reference (New Position):  SN 21949 18280 (LIDAR) 

Bwlch Height:  97.3m (LIDAR) 

Bwlch Grid Reference:  SN 22723 20183 (LIDAR) 

Drop:  52.8m (LIDAR) 

Dominance:  35.18% (LIDAR) 

 

Myrddyn Phillips (June 2023)

 

Mapping Mountains - Summit Relocations - 100m Twmpau

Parc Ffynnon (SN 199 192 & SN 200 192) - 42nd summit relocation

Significant Name Changes post for Parc Ffynnon

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Parc Ffynnon (SN 199 192 and SN 200 192)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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 100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Parc Ffynnon 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 minor roads to its west and east, and the A40 road to its south, and has the town of Hendy-gwyn ar Daf (Whitland) towards the south.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with an estimated c 145m summit height, based on interpolation of its uppermost 145m ring contour positioned at SN 20102 19284 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 143.7m positioned at SN 20028 19265.  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 Parc Ffynnon (SN 199 192 and SN 200 192) 

The height produced by LIDAR analysis to the natural summit of this hill is 143.6m and is positioned at SN 19998 19263 and SN 20001 19261 and SN 20005 19264, 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 143.6m and is positioned at SN 19998 19263 and SN 20001 19261 and SN 20005 19264, 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 105 metres westward from where the uppermost 145m contour ring appears on the contemporary Ordnance Survey 1:25,000 Explorer map, and approximately 25 metres westward from where the high point of the raised field boundary is positioned.

 

The full details for the hill are: 

Group:  Mynydd Preseli 

Name:  Parc Ffynnon 

OS 1:50,000 map:  158

Summit Height:  143.6m (LIDAR) 

Summit Grid Reference (New Position):  SN 19998 19263 & SN 20001 19261 & SN 20005 19264 (LIDAR) 

Bwlch Height:  98.0m (LIDAR) 

Bwlch Grid Reference:  SN 19882 19602 & SN 19884 19603 (LIDAR) 

Drop:  45.6m (LIDAR) 

 

Myrddyn Phillips (June 2023)

 

Mapping Mountains - Summit Relocations - 100m Twmpau

Mount Park (SN 072 185) - 41st summit relocation

Significant Name Changes post for Mount Park

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Mount Park (SN 072 185)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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 100m 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 Mount Park 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 encircled by minor roads, with the A40 road farther to its south and the B4313 road farther to its east, and has the town of Arberth (Narberth) towards the south-east.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a 112m summit height, based on the spot height positioned at SN 07177 18551 adjoined to a triangulation pillar which appears on the contemporary Ordnance Survey 1:50,000 Landranger and 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 112.0m positioned at SN 07201 18532.  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 Mount Park (SN 072 185)

The height produced by LIDAR analysis to the natural summit of this hill is 111.6m and is positioned at SN 07203 18543, 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 111.6m and is positioned at SN 07203 18543, 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 26 metres eastward from where the 112m spot height adjoined to the triangulation pillar is positioned and approximately 11 metres northward from where the high point of the raised field boundary is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Preseli 

Name:  Mount Park 

OS 1:50,000 map:  158

Summit Height:  111.6m (LIDAR) 

Summit Grid Reference (New Position):  SN 07203 18543 (LIDAR) 

Bwlch Height:  63.8m (LIDAR) 

Bwlch Grid Reference:  SN 04900 17196 (LIDAR) 

Drop:  47.8m (LIDAR) 

Dominance:  42.82% (LIDAR) 

 

Myrddyn Phillips (May 2023)

 

Mapping Mountains - Summit Relocations - 100m Twmpau

Morris’ Meadow (SN 019 183) - 40th summit relocation

Significant Height Revisions post for Morris' Meadow

Significant Name Changes post for Morris' Meadow

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Morris' Meadow (SN 019 183)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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 100m 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 Morris’ Meadow 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 encircled by minor roads, with the B4329 road farther to its west and the A40 road farther to its south, and has the town of Hwlffordd (Haverfordwest) towards the west south-west.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a summit height of 122m, based on the spot height positioned at SN 02261 18187 which 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. 

LIDAR summit image of Morris' Meadow (SN 019 183)

The summit height produced by LIDAR analysis is 119.4m positioned at SN 01923 18373, 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 summit height produced by LIDAR analysis is 119.4m and this is positioned at SN 01923 18373, this position is close to where a 120m spot height appears on the contemporary Ordnance Survey 1:25,000 Explorer map, and is approximately 190 metres north-westward from where the originally listed summit is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Preseli 

Name:  Morris’ Meadow 

OS 1:50,000 map:  157, 158

Summit Height:  119.4m (LIDAR) 

Summit Grid Reference (New Position):  SN 01923 18373 (LIDAR) 

Bwlch Height:  65.2m (LIDAR) 

Bwlch Grid Reference:  SN 01619 20933 (LIDAR) 

Drop:  54.2m (LIDAR) 

Dominance:  45.41% (LIDAR) 

 

Myrddyn Phillips (April 2023)

 

Mapping Mountains - Summit Relocations - 100m Twmpau

Carn Gelli (SM 923 379) - 39th summit relocation

Significant Height Revisions post for Carn Gelli

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Carn Gelli (SM 923 379)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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 100m Twmpau by Myrddyn Phillips

The name the hill is listed by is Carn Gelli, 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 A487 road farther to its south-east, and has the town of Abergwaun (Fishguard) towards the east south-east. 

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

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed with a summit height of 188m, based on the spot height positioned at SM 92271 38018 that appears on the Ordnance Survey 1:25,000 Explorer map, with an accompanying note stating; 191m on 2002 1:50,000 map. 

Extract from the Ordnance Survey 1:50,000 Landranger 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 Carn Gelli (SM 923 379)

The height produced by LIDAR analysis to the summit of this hill is 190.7m positioned at SM 92313 37943, as opposed to the old listed summit which LIDAR gives as 188.0m positioned at SM 92279 38013, 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 summit height produced by LIDAR analysis is 190.7m and this is positioned at SM 92313 37943, this position is not given a spot height on the contemporary Ordnance Survey 1:25,000 Explorer map, and is positioned to a different rock tor approximately 70 metres southward from where the originally listed summit is positioned. 

 

The full details for the hill are: 

Group:  Garn Fawr 

Name:  Carn Gelli 

OS 1:50,000 map:  157

Summit Height:  190.7m (LIDAR) 

Summit Grid Reference (New Position):  SM 92313 37943 (LIDAR) 

Bwlch Height:  128m (spot height) 

Bwlch Grid Reference:  SM 91953 38745 (spot height) 

Drop:  63m (LIDAR summit and spot height bwlch) 

 

Myrddyn Phillips (April 2023)

Mapping Mountains - Summit Relocations - 100m Twmpau

Carn Gelli (SM 982 375) - 38th summit relocation

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Carn Gelli (SM 982 375)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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 100m 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 Carn Gelli, 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 west and the A487 road to its south, and has the town of Abergwaun (Fishguard) towards the west.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed under the name of Carn Bica (latterly listed as Cnwc y Meirch) with a summit height of 143m, based on a spot height positioned at SM 98226 37698 and which appears on the Ordnance Survey 1:25,000 Explorer map.  With a separate summit named Carn Gelli positioned to the south and which has an uppermost 140m contour but no spot height on contemporary Ordnance Survey maps. 

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 Carn Gelli (SM 982 375) with Cnwc y Meirch (SM 982 376) to the north

The summit height produced by LIDAR analysis for Carn Gelli is 143.6m positioned at SM 98233 37531, whilst the height produced by LIDAR analysis for Cnwc y Meirch is 143.3m positioned at SM 98231 37693, 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 summit height produced by LIDAR analysis is 143.6m and this is positioned at SM 98233 37531, 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 rock tor approximately 160 metres southward from where the originally listed summit is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Preseli 

Name:  Carn Gelli 

OS 1:50,000 map:  157

Summit Height:  143.6m (LIDAR) 

Summit Grid Reference (New Position):  SM 98233 37531 (LIDAR) 

Bwlch Height:  87.7m (LIDAR) 

Bwlch Grid Reference:  SM 99189 36904 (LIDAR) 

Drop:  55.8m (LIDAR) 

Dominance:  38.90% (LIDAR) 

 

Myrddyn Phillips (March 2023) 

Mapping Mountains - Summit Relocations - 100m Twmpau

Pt. 141.4m (SN 416 592) - 37th summit relocation

Significant Name Changes post for Pt. 141.4m

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Pt. 141.4m (SNN 416 592)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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 100m Twmpau by Myrddyn Phillips

The hill is being listed by the point (Pt. 141.4m) notation as an appropriate name for it either through local enquiry and/or historic research has not been found by the author, and it is adjoined to the Mynydd Bach group of hills, which are situated in the western part of South Wales (Region B, Sub-Region B1), and it is positioned with the coast to its north, minor roads to its west and south-east, and the B4342 road to its south, and has the town of Ceinewydd (New Quay) towards the west.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a 141m summit height, based on the spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and which is positioned at SN 41695 59277. 

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 141.5m positioned at SN 41667 59283.  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 Pt. 141.4m (SN 416 592)

The height produced by LIDAR analysis to the natural summit of this hill is 141.35m and is positioned at SN 41655 59248, and this 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 of the hill 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 height produced by LIDAR analysis to the natural summit of this hill is 141.35m and is positioned at SN 41655 59248, 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 40 metres westward from where the 141m spot height is positioned and 35 metres southward from where the high point of the raised field boundary is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Bach 

Name:  Pt. 141.4m 

OS 1:50,000 map:  146

Summit Height:  141.35m (LIDAR) 

Summit Grid Reference (New Position):  SN 41655 59248 (LIDAR) 

Bwlch Height:  c 113m (interpolation) 

Bwlch Grid Reference:  SN 42778 58551 (interpolation) 

Drop:  c 28m (LIDAR summit and interpolated bwlch) 

 

Myrddyn Phillips (January 2023)

 

Mapping Mountains - Summit Relocations - 100m Twmpau

Banc Uchaf (SN 526 471) - 36th summit relocation

Significant Name Changes post for Banc Uchaf

 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Banc Uchaf (SN 526 471)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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 100m Twmpau by Myrddyn Phillips

The name the hill is listed by is Banc Uchaf and this was derived from the Tithe map, and it is adjoined to the Mynydd Bach group of hills, which are situated in the western part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its north and west, the A475 road to its south and the B4337 road to its north-east, and has the town of Llanbedr Pont Steffan (Lampeter) towards the east.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a c 180m summit height, based on the highest and largest ring contour that is positioned at SN 526 471 and appears on the Ordnance Survey 1:25,000 Explorer map, with an accompanying note stating; Two points same height – other at SN 514 472. 

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 184.0m positioned at SN 52613 47184.  However, this is a part of a raised copse 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 Banc Uchaf (SN 526 471)

The height produced by LIDAR analysis to the natural summit of this hill is 183.9m and is positioned at SN 52615 47176, and this 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 of the hill 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 height produced by LIDAR analysis to the natural summit of this hill is 183.9m and is positioned at SN 52615 47176, 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 8 metres southward from where the high point of the raised copse field boundary is positioned.

 

The full details for the hill are: 

Group:  Mynydd Bach 

Name:  Banc Uchaf 

OS 1:50,000 map:  146

Summit Height:  183.9m (LIDAR) 

Summit Grid Reference (New Position):  SN 52615 47176 (LIDAR) 

Bwlch Height:  150.95m (LIDAR) 

Bwlch Grid Reference:  SN 51628 47512 (LIDAR) 

Drop:  33.0m (LIDAR) 

 

Myrddyn Phillips (January 2023)