Myrddyn Phillips - Mapping Mountains: Mapping Mountains – Summit Relocations

Y Trechol –The Dominant Hills of Wales – Summit Relocations

Y Trechol –The Dominant Hills of Wales are the Welsh P30 hills whose prominence equal or exceed half that of their absolute height, accompanying the Dominant list is a sub list entitled The Lesser Dominant Hills of Wales with the criteria for this sub category being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height. The list commenced publication on Mapping Mountains on 03.012.15 with its Introduction giving details to its compilation and criteria, with Change Registers also created for the Dominant and the Lesser Dominant category.

The list is authored by Myrddyn Phillips and the posts that have appeared on Mapping Mountains detailing the summit relocations to the Dominant and Lesser Dominant list appear below presented chronologically in receding order.

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Trostrey Hill (SO 369 051) - 35th summit relocation

Hill Reclassification post for Trostrey Hill

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 confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Trostrey Hill (SO 369 051)

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 with 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 Trostrey Hill and it is adjoined to the Mynyddoedd Duon group of hills which are situated in the eastern part of South Wales (Region C, Sub-Region C3), and it is positioned with the Afon Wysg (River Usk) and the B4598 road to its west, the A40 road to its north, the A472 road to its south and the A449 road to its east, and has the village of Raglan towards the east north-east and the town of Brynbuga (Usk) 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 199m 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 adjoined to a triangulation pillar positioned at SO 36917 05185.

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

The details for this hill were re-evaluated when the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online, and as this map gives no further details the summit location remained the same.

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 Trostrey Hill (SO 369 051)

The summit height produced by LIDAR analysis to remaining natural ground is 199.3m positioned at SO 36920 05188 with LIDAR also giving a 199.5m height positioned at SO 36920 05184 to a raised field boundary that is excluded from the height of this hill as it is considered a recent man-made construct. The above detail comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

Therefore, the summit height produced by LIDAR analysis is 199.3m to ground meeting the criteria used within this list and this is positioned at SO 36920 05188, this is approximately 4 metres from where LIDAR gives the high point of the raised field boundary, but as this is considered a relatively recent man-made construct it is not taken as a part of the height of this hill.

The full details for the hill are:

Group: Mynyddoedd Duon

Name: Trostrey Hill

OS 1:50,000 map: 161

Summit Height: 199.3m (LIDAR)

Summit Grid Reference (New Position): SO 36920 05188 (LIDAR)

Bwlch Height: 129.1m (LIDAR)

Bwlch Grid Reference: SO 37462 05935 (LIDAR)

Drop: 70.2m (LIDAR)

Dominance: 35.23% (LIDAR)

Myrddyn Phillips (March 2020)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Coed y Bwnydd (SO 366 069) - 34th summit relocation

Hill Reclassifications post for Coed y Bwnydd

Significant Name Changes post for Coed y Bwnydd

Significant Height Revisions post for Coed y Bwnydd

There has been a Summit Relocation to a hill that is listed in the 200m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Coed y Bwnydd (SO 366 069)

The criteria for the two listings this summit relocation affects are:

200m Twmpau – Welsh hills at or above 200m and below 300m in height that have 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 200m and below 300m in height with 20m or more and below 30m of drop.

200m 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 3rd 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 y Bwnydd and it is adjoined to the Mynyddoedd Duon group of hills which are situated in the eastern part of South Wales (Region C, Sub-Region C3), and it is positioned with the Afon Wysg (River Usk) and the B4598 road to its west, the A40 road to its north and the A449 road to its east, and has the village of Raglan towards the east north-east and the town of Brynbuga (Usk) towards the south south-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 main P30 list under the name of Clytha Hill and listed with a 196m summit height, based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map at SO 368 069.

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

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online. This mapping had many spot heights not on other publicly available Ordnance Survey maps and gives a second 196m spot height on the summit area of this hill and positioned at SO 367 069. This additional 196m spot height also appears on Ordnance Survey data available on the Magic Maps website.

Extract from the Magic Maps website

LIDAR summit image of Coed y Bwnydd (SO 366 069)

The summit height produced by LIDAR analysis is 201.4m positioned at SO 36613 06919. The above detail comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

Therefore, the summit height produced by LIDAR analysis is 201.4m positioned at SO 36613 06919, this position is to an embankment that is a part of an ancient hill fort and this ground meets the criteria used within this list, and is approximately 120 metres westward from where the previous listed summit is positioned.

The full details for the hill are:

Group: Mynyddoedd Duon

Name: Coed y Bwnydd

OS 1:50,000 map: 161

Summit Height: 201.4m (LIDAR)

Summit Grid Reference (New Position): SO 36613 06919 (LIDAR)

Bwlch Height: 59.4m (LIDAR)

Bwlch Grid Reference: SO 39308 08901 (LIDAR)

Drop: 142.0m (LIDAR)

Dominance: 70.50%

Myrddyn Phillips (February 2020)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Wenvoe Quarry (ST 131 741) - 33rd summit relocation

Significant Name Changes post for Wenvoe Quarry

Significant Height Revisions post for Wenvoe Quarry

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 and its position confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR summit image of Wenvoe Quarry (ST 131 741)

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 with 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.

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.

The name the hill is now listed by is Wenvoe Quarry and it is adjoined to the Bro Morgannwg group of hills, which are situated in the southern part of South Wales (Region C, Sub-Region C2), and it is positioned with a number of A roads encircling it with the A4232 to its north and east, the A4050 to its west and the A4055 further to its south-east, and has the city of Caerdydd (Cardiff) towards the north-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 115m summit height positioned at ST 132 742, based on the uppermost contour on contemporary Ordnance Survey 1:25,000 Explorer maps.

When this 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 117m summit height based on interpolation of the uppermost 115m contour on the Ordnance Survey 1:25,000 Explorer map, with this summit height later being changed to an estimated c 118m and with its summit position listed as ST 130 742.

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

The height produced by LIDAR analysis is 123.4m and is positioned at ST 13189 74189, and the above detail comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.

Therefore, the summit height produced by LIDAR analysis is 123.4m and this is positioned at ST 13189 74189, and this is approximately 130 metres south-eastward from where the estimated c 118m summit position was previously given.

The full details for the hill are:

Group: Bro Morgannwg

Name: Wenvoe Quarry

OS 1:50,000 map: 171

Summit Height: 123.4m (LIDAR)

Summit Grid Reference (New Position): ST 13189 74189 (LIDAR)

Bwlch Height: 66m (spot height)

Bwlch Grid Reference: ST 12669 74393 (spot height)

Drop: 57m (LIDAR summit and spot height bwlch)

Dominance: 46.51% (LIDAR summit and spot height bwlch)

Myrddyn Phillips (October 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Cock Hill (ST 153 750) - 32nd summit relocation

Significant Name Changes post for Cock Hill

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 and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Cock Hill (ST 153 750)

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

The name of the hill is Cock Hill and it is adjoined to the Bro Morgannwg group of hills, which are situated in the southern part of South Wales (Region C, Sub-Region C2), and it has the A4232 road to its north and east and a minor road towards its south, and has the city of Caerdydd (Cardiff) towards the north-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 115m summit height positioned at ST 153 750, based on the uppermost ring contour that appears on contemporary Ordnance Survey 1:25,000 Explorer maps which takes in a triangulation pillar with an adjoining flush bracket height of 115.345m positioned at ST 15338 75022.

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

LIDAR summit image of Cock Hill

The summit height produced by LIDAR analysis is 115.6m positioned at ST 15303 75089 with LIDAR also giving a 115.7m height positioned at ST 15310 75062 to a raised field boundary that is excluded from the height of this hill as it is considered a recent man-made construct and with the natural summit of the hill positioned in a different field compared to where the summit was originally listed. The above detail comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.

Therefore, the summit height produced by LIDAR analysis is 115.6m to ground meeting the criteria used within this list and this is positioned at ST 15303 75089, this is in a different field to the previously listed summit position and is approximately 80 metres north-westward from it and approximately 28 metres from where the highest part of the raised field boundary is situated, and as the latter is considered a relatively recent man-made construct it is not taken as a part of the height of this hill.

The full details for the hill are:

Group: Bro Morgannwg

Name: Cock Hill

OS 1:50,000 map: 171

Summit Height: 115.6m (LIDAR, natural summit)

Summit Grid Reference (new position): ST 15303 75089 (LIDAR, natural summit)

Bwlch Height: 46.3m (LIDAR)

Bwlch Grid Reference: ST 13392 74714 (LIDAR)

Drop: 69.3m (LIDAR)

Dominance: 59.92% (LIDAR)

Myrddyn Phillips (September 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Pt. 103.2m (SS 923 719) - 31st 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 and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR summit image of Pt. 103.2m (SS 923 719)

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

The hill is being listed by the Point (Pt. 103.2m) notation as I do not know an appropriate name for it either from historic research or local enquiry, and it is adjoined to the Bro Morgannwg group of hills, which are situated in the southern part of South Wales (Region C, Sub-Region C2), and it is positioned with the B4265 to its north-east and minor roads to its north and west, and has the small community of Y Wig (Wick) towards the north.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website this hill was listed with a 102m summit height, based on the spot height positioned at SS 921 719 that appears on the Ordnance Survey 1:25,000 Explorer map.

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

The details for this hill were re-evaluated when the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online, and as this map gives a 103m spot height positioned at SS 92333 71971, the summit of this hill was relocated.

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

Close up LIDAR summit image of Pt. 103.2m (SS 923 719)

The summit height produced by LIDAR analysis is 103.2m positioned at SS 92366 71993 with LIDAR also giving a 103.4m height positioned at SS 92370 72054 to a raised field boundary that is excluded from the height of this hill as it is considered a recent man-made construct. The above detail comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.

Therefore, the summit height produced by LIDAR analysis is 103.2m to ground meeting the criteria used within this list and this is positioned at SS 92366 71993, this is relatively close to where the 103m spot height appears on the Ordnance Survey Vector Map Local hosted on the Geograph website and is positioned approximately 170 metres east north-eastward from where the 102m spot height appears on the Ordnance Survey 1:25,000 Explorer map and approximately 60 metres from where the highest part of the raised field boundary is situated, and as the latter is considered a relatively recent man-made construct it is not taken as a part of the height of this hill.

The full details for the hill are:

Group: Bro Morgannwg

Name: Pt. 103.2m

OS 1:50,000 map: 170

Summit Height: 103.2m (LIDAR, natural summit)

Summit Grid Reference (new position): SS 92366 71993 (LIDAR, natural summit)

Bwlch Height: 59.4m (LIDAR)

Bwlch Grid Reference: SS 97154 74620 & SS 97156 74616 & SS 97158 74613 (LIDAR)

Drop: 43.8m (LIDAR)

Dominance: 42.43% (LIDAR)

Myrddyn Phillips (September 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Tair Onnen (ST 036 739) - 30th summit relocation

LIDAR image of Tair Onnen (ST 036 739)

There has been a Summit Relocation to a hill that is listed in the Y Trechol – The Dominant Hills of Wales, with the summit height and its location confirmed by a Leica GS15 survey conducted by John Barnard, Graham Jackson and Myrddyn Phillips which took place on the 4^th November 2013.

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

The name of the hill is Tair Onnen, and it is adjoined to the Bro Morgannwg group of hills, which are situated in the southern part of South Wales (Region C, Sub-Region C2), and it is positioned with the A48 road to its north and minor roads to its south, and has the town of Y Bont-faen (Cowbridge) towards the west and the city of Caerdydd (Cardiff) towards the east.

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

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

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

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 either the main P30 or accompanying Hills to be surveyed sub list as with a 137m summit height adjoined to its triangulation pillar it was deemed lower than Cae Cefn (ST 059 748) which has a 140m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map, resulting in Cae Cefn being listed as the Dominant hill with 51.43% dominance. However, as the 140m spot height is to the top of a covered reservoir and as these structures are considered recent man-made constructs the two hills were subsequently surveyed using a Leica GS15 resulting in the following details.

Cae Cefn (ST 05910 74886): 136.2m (natural ground at base of covered reservoir)

Tair Onnen (ST 03660 73979): 137.3m

When LIDAR became available the details for these two hills were re-assessed. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. The LIDAR summit details are given below:

Cae Cefn (ST 05915 74885): 136.4m (natural ground at base of covered reservoir)

Tair Onnen (ST 03661 73979): 137.4m

LIDAR image of Cae Cefn (ST 059 748)

The summit height produced by the Leica GS15 survey and by LIDAR analysis gives the summit of Tair Onnen as higher than the natural ground at the immediate base of the covered reservoir on Cae Cefn, and as such this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.

Gathering data with the Leica GS15 at the summit of Tair Onnen

Gathering data with the Leica GS15 at the summit of Cae Cefn

Therefore, the summit height produced by the Leica GS15 survey is 137.3m and this is positioned at ST 03660 73979, this position is beside the triangulation pillar atop Tair Onnen and is approximately 2.3km west south-westward from where the originally listed summit of Cae Cefn is positioned.

The full details for the hill are:

Group: Bro Morgannwg

Name: Tair Onnen

OS 1:50,000 map: 170

Summit Height: 137.3m (Leica GS15)

Summit Grid Reference (new position): ST 03660 73979 (Leica GS15)

Bwlch Height: c 67m (interpolation)

Bwlch Grid Reference: ST 01235 77663 (interpolation)

Drop: c 70m

Dominance: 51.20%

Myrddyn Phillips (September 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

The Beech (ST 346 974) - 29th summit relocation

Significant Name Changes post for The Beech

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 and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of The Beech (ST 346 974)

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

The name the hill is now listed by is The Beech and it is adjoined to the Cymoedd Gwent group of hills, which are situated in the eastern part of South Wales (Region C, Sub-Region C2), and it has a number of A roads encircling it with the A4042 to its west, the A472 to its north, the A449 to its east and the M4 motorway towards its south, and has the town of Brynbuga (Usk) towards its north-east.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website this hill was listed with a 184m summit height, based on the spot height positioned at ST 346 974 that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, with the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map positioning this spot height on the south-east side of a field boundary.

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

The summit height produced by LIDAR analysis is 185.4m positioned at ST 34645 97459 with LIDAR also giving a 185.5m height positioned at ST 34663 97467 to the raised field boundary that is excluded from the height of this hill as it is considered a recent man-made construct. Importantly the natural summit position of this hill is given by LIDAR to the north-west of the raised field boundary, and as such comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.

Therefore, the summit height produced by LIDAR analysis is 185.4m to natural ground and this is positioned at ST 34645 97459, and although relatively close to where 184m spot height appears on the Ordnance Survey Vector Map Local hosted on the Geograph website, it is positioned in a different field from where the originally listed summit adjoined to this spot height is placed.

The full details for the hill are:

Group: Cymoedd Gwent

Name: The Beech

OS 1:50,000 map: 171

Summit Height: 185.4m (LIDAR, natural summit)

Summit Grid Reference (new position): ST 34645 97459 (LIDAR, natural summit)

Bwlch Height: 89.0m (LIDAR)

Bwlch Grid Reference: ST 34479 98091 (LIDAR)

Drop: 96.4m (LIDAR)

Dominance: 51.98% (LIDAR)

Myrddyn Phillips (September 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Woodlake Park (ST 343 997) - 28th summit relocation

Significant Name Changes post for Woodlake Park

Significant Height Revisions post for Woodlake Park

There has been confirmation of 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 and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Woodlake Park (ST 343 997)

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

The name the hill is listed by is Woodlake Park and it is adjoined to the Cymoedd Gwent group of hills, which are situated in the eastern part of South Wales (Region C, Sub-Region C2), and it is positioned above the Llandegfedd Reservoir which is to its west, and has the town of Pont-y-pŵl (Pontypool) towards its west and Brynbuga (Usk) towards its east.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website this hill was listed with a 147m summit height, based on the spot height positioned at ST 340 994 that appears on the Ordnance Survey 1:50,000 Landranger map, with the 1:25,000 Explorer map having no spot height.

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

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

The details for this hill were re-evaluated when the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online, and as this map gives a 149m spot height positioned at ST 34341 99786, the summit of this hill was relocated.

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

The height produced by LIDAR analysis is 150.7m positioned at ST 34335 99793, this confirms the summit relocation from its position originally given in the 100m P30 list of Geoff Crowder’s v-g.me website, and as such comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

Therefore, the height produced by LIDAR analysis is 150.7m and this is positioned at ST 34335 99793, this position is close to where the 149m spot height appears on the Ordnance Survey Vector Map Local hosted on the Geograph website and is approximately 450 metres north north-east from where the originally listed summit adjoined to the 147m spot height is positioned.

The full details for the hill are:

Group: Cymoedd Gwent

Name: Woodlake Park

OS 1:50,000 map: 171

Summit Height: 150.7m (LIDAR)

Summit Grid Reference (new position): ST 34335 99793 (LIDAR)

Bwlch Height: 91.5m (LIDAR)

Bwlch Grid Reference: SO 33405 01033 (LIDAR)

Drop: 59.3m (LIDAR)

Dominance: 39.31% (LIDAR)

Myrddyn Phillips (August 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

The Mount (ST 258 848) - 27th summit relocation

Significant Name Changes post for The Mount

Significant Height Revisions post for The Mount

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 derived from the OS Trig Database and the bwlch height derived from interpolation of 5m contouring.

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

The name of the hill is The Mount and it is adjoined to the Cymoedd Gwent group of hills, which are situated in the eastern part of South Wales (Region C, Sub-Region C2), and it has minor roads to its north-west and north-east and the M4 motorway to its south, and is positioned between the city of Caerdydd (Cardiff) to the south-west and Casnewydd-ar-Wysg (Newport) to the north-east.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website this hill was listed with a 124m summit height, based on the spot height positioned at ST 25276 84738 that appears on the Ordnance Survey 1:25,000 Explorer map, with an accompanying note stating that the Ordnance Survey 1:50,000 Landranger map dated 1986 has a 127m spot height adjoined to a triangulation pillar and which is positioned at ST 25869 84831. As heights on 1:25,000 scale mapping were prioritised in this list over those on 1:50,000 scale mapping this hill’s summit was listed to where the 124m spot height appears on the 1:25,000 Explorer map.

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

Since publication of these P30 lists on Geoff Crowder’s v-g.me website the heights on different scaled Ordnance Survey maps can be cross referenced against a number of sources that are now available online, and 1:25,000 map data is no longer prioritised for summit heights over that of 1:50,000 map data, each is now assessed individually.

The summit height adjoined to the old triangulation pillar and its position in relation to that previously given comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

Therefore, the listed summit height of this hill is 127m and this was derived from the 127.247m flush bracket height adjoined to a triangulation pillar that once stood on the summit of this hill and which was destroyed in September 1985, this position is approximately 550 metres eastward from the previously listed summit position where the 124m spot height appears on the Ordnance Survey 1:25,000 Explorer map.

The full details for the hill are:

Group: Cymoedd Gwent

Name: The Mount

OS 1:50,000 map: 171

Summit Height: 127m

Summit Grid Reference (new position): ST 25868 84839

Bwlch Height: c 66m

Bwlch Grid Reference: ST 24800 87551

Drop: c 61m

Dominance: 48.03%

Myrddyn Phillips (August 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Ynys Bery (SM 701 219) - 26th summit relocation

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The full details for the hill are:

Group: Carn Llidi

Name: Ynys Bery

OS 1:50,000 map: 157

Summit Height: 72.0m (LIDAR)

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

Bwlch Height: N/A, sea level

Bwlch Grid Reference: N/A, sea level

Drop: 72.0m (LIDAR)

Dominance: 100.00% (LIDAR)

Remoteness: 3.925 km

Myrddyn Phillips and Aled Williams (July 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Mynydd y Lan (ST 209 923) - 25th summit relocation

Significant Height Revisions post for Mynydd y Lan

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

LIDAR image of Mynydd y Lan (ST 209 923)

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

Y Trichant – Welsh hills at or above 300m and below 400m in height with 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017.

The name of the hill is Mynydd y Lan and it is adjoined to the Cymoedd Gwent group of hills, which are situated in the eastern part of South Wales (Region C, Sub-Region C2), and it is encircled by roads with the B4251 to its south and west, the A472 to its north and the A467 and B4591 and the Afon Ebwy (Ebbw River) to its east, and has the town of Trecelyn (Newbridge) towards the north and the village of Pontycymer (Crosskeys) towards the east.

When the original Welsh 300m P30 list was published on Geoff Crowder’s v-g.me website this hill was listed with a 381m summit height, based on the spot height positioned at ST 20794 92508 that appears on the Ordnance Survey 1:25,000 Explorer map, with an accompanying note stating that the Ordnance Survey 1:50,000 Landranger map has a 385m spot height positioned at ST 20898 92357. As heights on 1:25,000 scale mapping were prioritised in this list over those on 1:50,000 scale mapping this hill’s summit was listed to where the 381m spot height appears on the 1:25,000 Explorer map.

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

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

Since publication of these P30 lists on Geoff Crowder’s v-g.me website there have been a number of Ordnance Survey 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 are current and digitally updated such as the Vector Map Local hosted on the Geograph website, and which is entitled the Interactive Coverage Map, and in the case of this hill it is the series of Ordnance Survey Six-Inch maps where the origins of the 385m spot height that appears on the 1:50,000 Landranger map can be traced, as the Six-Inch map surveyed in 1875 and published in 1885 has a 1263.6ft (385.15m) surface height at the same position as the contemporary 385m spot height.

Extract from the Ordnance Survey series of Six-Inch maps

LIDAR summit image of Mynydd y Lan

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

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

The summit height produced by LIDAR analysis is 381.3m and is positioned at ST 20903 92337, this position is given a 385m spot height on contemporary Ordnance Survey 1:50,000 Landranger maps and is approximately 200 metres south south-eastward from the previously listed summit position where the 381m spot height appears on the Ordnance Survey 1:25,000 Explorer map.

The full details for the hill are:

Group: Cymoedd Gwent

Name: Mynydd y Lan

OS 1:50,000 map: 171

Summit Height: 381.3m (LIDAR)

Summit Grid Reference (new position): ST 20903 92337 (LIDAR)

Bwlch Height: 159.5m (LIDAR)

Bwlch Grid Reference: ST 19806 96725 (LIDAR)

Drop: 221.8m (LIDAR)

Dominance: 58.17% (LIDAR)

Myrddyn Phillips (July 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Plas Gwyn (SH 524 817) - 24th summit relocation

Survey post for Plas Gwyn

Significant Name Changes post for Plas Gwyn

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

Plas Gwyn (SH 524 817)

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

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

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

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

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

LIDAR image of the summit of Plas Gwyn

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

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

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

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

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

The full details for the hill are:

Group: Ynys Môn

Name: Plas Gwyn

OS 1:50,000 map: 114, 115

Summit Height: 76.1m (converted to OSGM15)

Summit Grid Reference (new position): SH 52494 81743

Bwlch Height: 41.9m (LIDAR)

Bwlch Grid Reference: SH 52209 81404 (LIDAR)

Drop: 34.2m (Trimble summit and LIDAR bwlch)

Dominance: 44.91% (Trimble summit and LIDAR bwlch)

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

Myrddyn Phillips (May 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Cae Alen (SH 781 758) - 23rd summit relocation

Survey post for Cae Alen

Significant Name Changes post for Cae Alen

There has been a Summit Relocation to a hill that is listed in the Y Trechol – The Dominant Hills of Wales, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis, and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the latter taking place on the 10^th October 2018.

LIDAR image of Cae Alen, Bwlch Mawr and Bryn Eithin

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

The name of the bounded land where the summit of this hill is situated is Cae Alen and this was derived from the Tithe map, and it is this name that the hill is now listed by. The hill is adjoined to the Carneddau group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the B5106 road to its west and the Afon Conwy (River Conwy) to its east, and has the town of Conwy towards its north.

This summit relocation relates to three points, two of which are adjoined with the most northerly given a 130m summit spot height positioned at SH 781 758 on contemporary Ordnance Survey maps, this is adjoined to the central point which is given a small uppermost 130m ring contour positioned at SH 777 755, whilst the most southerly point is a separate P30 and also given a small uppermost 130m ring contour positioned at SH 775 752.

When the origin 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, two of these points were listed as separate P30s; with the northerly 130m map heighted summit positioned at SH 781 758 being prioritised over that of the central point positioned at SH 777 755.

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

The details for these hills were re-assessed when the Ordnance Survey Vector Map Local became available online, this map is hosted on the Geograph website and is entitled the Interactive Coverage Map, and as an uppermost contour ring should be prioritised over that of a same map heighted spot height the central point positioned at SH 777 755 was now prioritised for P30 status over the northerly 130m spot heighted point positioned at SH 781 758. However, it was the southerly summit positioned at SH 775 752 that was now prioritised over the central summit positioned at SH 777 755 for Dominant status.

It was not until LIDAR became available and analysed that the details for these hills 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 Bryn Eithin

The height produced by LIDAR analysis and a subsequent survey with the Trimble GeoXH 6000 confirmed the northerly summit as higher:

Northerly summit; Cae Alen: 129.1m at SH 78116 75814

Central summit; Bwlch Mawr: 128.4m at SH 77790 75561

Southerly summit; Bryn Eithin: 128.5m at SH 77584 75224

This comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

The Trimble GeoXH 6000 gathering data at the summit of Cae Alen

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

Therefore the height produced by the Trimble GeoXH 6000 survey is 129.1m positioned at SH 78116 75814, this position is given a 130m spot height on contemporary Ordnance Survey maps and is approximately 800m north-east from where the previously listed Dominant summit is situated which was surveyed as being 128.5m in height and positioned at SH 77584 75224.

The full details for the hill are:

Group: Carneddau

Name: Cae Alen

OS 1:50,000 map: 115

Summit Height: 129.1m (converted to OSGM15)

Summit Grid Reference (new position): SH 78116 75814

Bwlch Height: 34.8m (LIDAR)

Bwlch Grid Reference: SH 77629 74003 (LIDAR)

Drop: 94.3m (Trimble summit and LIDAR bwlch)

Dominance: 73.05% (Trimble summit and LIDAR bwlch)

For details of the summit survey of this hill

Myrddyn Phillips (April 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Cae Felin Wynt (SS 683 954) - 22nd summit relocation

Significant Name Changes post for Cae Felin Wynt

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, its location, the drop and status of the hill being confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Cae Felin Wynt (SS 683 954)

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

The name of the bounded land where the summit of this hill is situated is Cae Felin Wynt and this was derived from the Tithe map, and it is this name that the hill is now listed by. The hill is adjoined to the Fforest Fawr group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C2), and it is positioned with the B5444 and the A4217 roads to its west and the Crymlyn Bog to its east, and has the city of Abertawe (Swansea) towards the west south-west.

When this hill was originally listed in the 100m height band of Welsh P30 hills on Geoff Crowder’s v-g.me website, its summit was listed at SS685956 and it appeared with an accompanying note stating; Two points of same height – other at SS681955.

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

Prior to LIDAR analysis this hill was listed with 43m of drop, based on the prioritised 117m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and which is adjoined to a triangulation pillar positioned at SS 68464 95622 and the 74m bwlch spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.

The second 117m map spot height is positioned at SS 68178 95486 with ground to its east leading to a covered reservoir. The ground at and also close to where each 117m map spot height appears was analysed via LIDAR resulting in the highest natural ground being positioned close to the north-east corner of the covered reservoir, signifying that the natural summit of this hill is now under this man-made construction.

LIDAR close up image of the summit of Cae Felin Wynt

The height produced by LIDAR analysis to the highest natural ground is 118.9m positioned at SS 68320 95490, with LIDAR contouring indicating that the natural summit of this hill is now under the covered reservoir, but as the remaining natural ground beside the covered reservoir is higher than that beside the old listed summit adjacent to the 117m map heighted trig pillar and is at least 100 metres in distance from it this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

The Ordnance Survey's Vector Map Local hosted on the Geograph website with the highest natural ground circled

Therefore the height produced by LIDAR analysis is 118.9m to natural ground and this is positioned at SS 68320 95490, this position is not given a spot height on Ordnance Survey maps and is approximately 200 metres south-westward from where the previously listed summit position is situated beside the 117m map heighted trig pillar that appears on contemporary Ordnance Survey maps.

The full details for the hill are:

Group: Fforest Fawr

Name: Cae Felin Wynt

OS 1:50,000 map: 159

Summit Height: 118.9m (LIDAR, natural ground)

Summit Grid Reference: SS 68320 95490 (LIDAR, natural ground)

Bwlch Height: 74.2m (LIDAR)

Bwlch Grid Reference: SS 67837 95105 (LIDAR)

Drop: 44.7m (LIDAR)

Dominance: 37.57% (LIDAR)

Myrddyn Phillips (April 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Clytiau Poethion (SH 763 717) - 21st summit relocation

Survey post for Clytiau Poethion

Significant Name Changes post for Clytiau Poethion

There has been a Summit Relocation to a hill that is listed in the Y Trechol – The Dominant Hills of Wales, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis, and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the latter taking place on the 10^th October 2018.

LIDAR image of Maes Glas Mawr and Clytiau Poethion

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

The name of the bounded land where the summit of this hill is situated is Clytiau Poethion, and this was derived from the Tithe map and it is the name that this hill is now listed by, and it is adjoined to the Carneddau group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and the hill is encircled by minor roads with the B5106 and the Afon Conwy (River Conwy) to its east, and has the town of Conwy to its north.

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website the adjacent northerly hill known as Maes Glas Mawr (SH 76876 72414) was included in the main P30 list as its summit was thought to be higher than that of Clytiau Poethion (SH 76337 71799), based on a 107m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger map as opposed to an upper 100m contour ring given to Clytiau Poethion.

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

Therefore, when the Dominant list was first compiled it was the hill now listed as Maes Glas Mawr that was included in the Lesser Dominant list with 36.45% dominance.

However, it was not until LIDAR became available that the details for each 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 Clytiau Poethion as higher than Maes Glas Mawr and this has subsequently been confirmed by a Trimble GeoXH 6000 survey, therefore the bylchau for each hill is swapped as are their classifications, resulting in a Trimble GeoXH 6000 summit height for Clytiau Poethion of 109.1m positioned at SH 76337 71799, as opposed to the 108.5m summit height for Maes Glas Mawr positioned at SH 76876 72414. This confirms the qualifying hill’s summit position compared to where previously listed, and it comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

LIDAR bwlch image for Clytiau Poethion

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 109.1m and is positioned at SH 76337 71799, this position is not given a spot height on contemporary Ordnance Survey maps and is approximately 800 metres south-westward from where the previously listed summit is positioned.

The full details for the hill are:

Group: Carneddau

Name: Clytiau Poethion

OS 1:50,000 map: 115

Summit Height: 109.1m (converted to OSGM15)

Summit Grid Reference (new position): SH 76337 71799

Bwlch Height: 68.7m (LIDAR)

Bwlch Grid Reference: SH 77496 72493 (LIDAR)

Drop: 40.35m (Trimble summit and LIDAR bwlch)

Dominance: 37.00% (Trimble summit and LIDAR bwlch)

For details on the summit survey of this hill

Myrddyn Phillips (April 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Pt. 118.9m (SN 710 294) - 20th summit relocation

Significant Name Changes post for Pt. 118.9m

There has been a Summit Relocation to a hill that is listed in the 100m Twmpau and the 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 Pt. 118.9m (SN 710 294)

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

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 inits entirety on Mapping Mountains in Google Doc format.

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The hill is being listed by the point (Pt. 118.9m) notation and it is adjoined to the Mynydd Du group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with the Afon Tywi (River Towy) and the A40 road to its west, the B4069 road to its east, and has the village of Llangadog towards the south.

When the original 100m height band of Welsh P30hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 category and listed with a 119m summit height based on the spot height positioned at SN 72465 30422 and 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

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 50m of drop and 42.02% dominance, based on the 119m summit spot height an estimated c 69m bwlch height, based on interpolation of 5m contouring between 65m - 70m that appeared on the OS Maps website.

LIDAR analysis gives the highest ground on this hill as 119.8m positioned at SN 71062 29399. 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. 118.9m (SN 710 294)

The height produced by LIDAR analysis to the natural ground of this hill is 118.0m and is positioned at SN 71046 29411, 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 118.9m and is positioned at SN 71046 29411, this position is clost to where the 119m spot height appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 18 metres north-westward from where the high point of the raised field boundary is positioned.

The full details for the hill are:

Group: Mynydd Du

Name: Pt. 118.9m

OS 1:50,000 map: 146, 160

Summit Height: 118.9m (LIDAR)

Summit Grid Reference: SN 71046 29411 (LIDAR)

Bwlch Height: 69.9m (LIDAR)

Bwlch Grid Reference: SN 72466 30393 (LIDAR)

Drop: 48.9m (LIDAR)

Dominance: 41.16% (LIDAR)

Myrddyn Phillips (February 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Yr Orsedd (SH 299 270) - 19th summit relocation

Survey post for Yr Orsedd

Significant Name Changes post for Yr Orsedd

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

Yr Orsedd (SH 299 270)

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

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

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

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

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

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

Bryn Tŷ Newydd (SH 295 265)

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

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

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

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

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

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

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

The full details for the hill are:

Group: Pen Llŷn

Name: Yr Orsedd

OS 1:50,000 map: 123

Summit Height: 67.5m (converted to OSGM15)

Summit Grid Reference (new position): SH 29952 27038

Bwlch Height: 32.0m (LIDAR)

Bwlch Grid Reference: SH 29808 27337 (LIDAR)

Drop: 35.4m (Trimble summit and LIDAR bwlch)

Dominance: 52.52% (Trimble summit and LIDAR bwlch)

For details on the summit survey of this hill

Myrddyn Phillips (February 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Cae Ddu Main (SN 622 983) - 18th summit relocation

Significant Name Changes post for Cae Ddu Main

Hill Reclassifications post for Cae Ddu Main

There has been a Summit Relocation to a hill that is listed in the 100m Twmpau and also now in Y Trechol – The Dominant Hills of Wales, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Cae Ddu Main

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

The name of the bounded land where the summit of this hill is situated is Cae Ddu Main and this was derived from the Tithe map, and it is this name that the hill is now listed by. The hill is adjoined to the Mynydd Penlle’rcastell group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C1), and is positioned with the A483 road to its immediate west and the A48 and M4 to its north, and has the village of Penlle’r-gaer to its north.

If wanting to visit the hill permission to do so should be sought as the summit area is not a part of designated open access land, for those wishing to do so an approach from the north may be feasible.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website the summit location of this hill was given to the 102m spot height that is positioned at SS 619 984 on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps. However, the 1:25,000 Explorer map has a small uppermost 105m ring contour to the east of the 102m spot height.

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

The summit relocation to land within the 105m ring contour has now been confirmed by LIDAR analysis and this land is confirmed as higher than that at the 102m spot height to its west.

The summit height produced by LIDAR analysis is 106.9m to remaining natural ground, and its position in relation to that originally given comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

The summit height produced by LIDAR analysis is 106.9m to remaining natural ground and is positioned at SS 62212 98337, this position is approximately 290 metres east from where the summit was originally listed at the position of the 102m spot height.

The full details for the hill are:

Group: Mynydd Penlle’rcastell

Name: Cae Ddu Main

OS 1:50,000 map: 159

Summit Height: 106.9m (LIDAR, remaining natural high point)

Summit Grid Reference (new position): SN 62212 98337 (LIDAR, remaining natural high point)

Bwlch Height: 69.1m (LIDAR, natural bwlch)

Bwlch Grid Reference: SN 62051 00000 (LIDAR, natural bwlch)

Drop: 37.8m (LIDAR)

Dominance: 35.34% (LIDAR)

Myrddyn Phillips (February 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Penrhos Garnedd (SH 560 702) - 17th summit relocation

Survey post for Penrhos Garnedd

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

The summit of Penrhos Garnedd (SH 560 702)

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

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

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

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

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

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

LIDAR image of Penrhos Garnedd

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

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

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

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

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

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

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

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

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

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

The full details for the hill are:

Group: Glyderau

Name: Penrhos Garnedd

OS 1:50,000 map: 114, 115

Summit Height: 94.0m (converted to OSGM15)

Summit Grid Reference (new position): SH 56027 70234

Bwlch Height: 40.4m (LIDAR)

Bwlch Grid Reference: SH 56305 70029 (LIDAR)

Drop: 53.7m (Trimble summit and LIDAR bwlch)

Dominance: 57.05% (Trimble summit and LIDAR bwlch)

My thanks to Aled Williams for his initial LIDAR analysis

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

Myrddyn Phillips (February 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Bryn (SH 426 361) - 16th summit relocation

Survey post for Bryn

Hill Reclassifications post for Bryn

Significant Name Changes post for Bryn

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

LIDAR image of the summit of Bryn

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

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

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

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

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

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

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

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

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

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

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

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

The Trimble GeoXH 6000 gathering data at the summit of Bryn

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

The full details for the hill are:

Group: Pen Llŷn

Name: Bryn

OS 1:50,000 map: 123

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

Summit Grid Reference: SH 42656 36173 (natural summit)

Bwlch Height: 6.6m (LIDAR)

Bwlch Grid Reference: SH 43103 36535 (LIDAR)

Drop: 30.0m (Trimble summit and LIDAR bwlch)

Dominance: 81.88% (Trimble summit and LIDAR bwlch)

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

Myrddyn Phillips (January 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Cae Ffwyn Uchaf (SN 588 005) - 15th summit relocation

Significant Name Changes post for Cae Ffwyn Uchaf

Hill Reclassifications post for Cae Ffwyn Uchaf

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

LIDAR image of Cae Ffwyn Uchaf

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

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

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

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

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

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

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

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

LIDAR image of the old listed summit position

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

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

The full details for the hill are:

Group: Mynydd Penlle’rcastell

Name: Cae Ffwyn Uchaf

OS 1:50,000 map: 159

Summit Height: 66.6m (LIDAR)

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

Bwlch Height: 36.0m (LIDAR, natural bwlch)

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

Drop: 30.6m (LIDAR)

Dominance: 45.90% (LIDAR)

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

Myrddyn Phillips (January 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Mynydd Gelliwastad (SN 678 015) - 14th summit relocation

There has been a Summit Relocation to a hill that is listed in the 200m Twmapu and Y Trechol – The Dominant Hills of Wales, with the summit height, drop and status of the hill being confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Mynydd Gelliwastad

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

200m Twmpau - Welsh hills at or above 200m and below 300m in height with 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 200m and below 300m 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 name of the hill is Mynydd Gelliwastad, and it is adjoined to the Mynydd Penlle’rcastell group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C1), and has the Lower Clydach River, the B 4603 and the A 4067 towards its east and the M 4 towards its south, and has the village of Clydach towards its east.

As the summit of the hill is a part of designated open access land it can be approached from most directions with public footpaths accessing this land from the north and the west.

Prior to LIDAR analysis this hill was listed with c 100m of drop based on the 213m height given to a triangulation pillar positioned at SN 67799 01456 that appears on Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and an estimated bwlch height of c 113m based on interpolation of 5m contours between 110m – 115m.

Close up LIDAR image of the summit of Mynydd Gelliwastad

LIDAR image of the bwlch of Mynydd Gelliwastad

The summit height produced by LIDAR analysis is 213.9m at SS 67852 01598 and its position in relation to that previously given comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

Extract from the Ordnance Survey 1:25,000 Explorer map showing the new summit position in relation to the old listed summit position at the trig pillar

The summit height produced by LIDAR analysis is 213.9m and is positioned at SN 67852 01598, this position is not given a spot height on contemporary Ordnance Survey maps but appears within an uppermost 210m contour ring. This position is approximately 100 metres north from where the previously listed summit is positioned.

The full details for the hill are:

Group: Mynydd Penlle’rcastell

Name: Mynydd Gelliwastad

OS 1:50,000 map: 159

Summit Height: 213.9m (LIDAR)

Summit Grid Reference (new position): SN 67852 01598 (LIDAR)

Bwlch Height: 114.8m (LIDAR)

Bwlch Grid Reference: SN 67677 02435 (LIDAR)

Drop: 99.1m (LIDAR)

Dominance: 46.33% (LIDAR)

Myrddyn Phillips (January 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Town Hill (SS 639 939) - 13th summit relocation

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

LIDAR image of Town Hill

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

The name of the hill is Town Hill, and it is adjoined to the Mynydd Penlle’rcastell group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C1), and it is encircled by A roads with the A 4216 to its west, the A 483 to its north and the A 4118 to its east and south, and it forms a part of the city of Abertawe (Swansea).

As the summit of this hill is positioned on a grass verge beside a road it can be approached from most directions, however be careful of the traffic!

Prior to LIDAR analysis the summit position of the Dominant hill was listed as SS 615 940, the hill at this position remains unnamed on Ordnance Survey maps and therefore it is now listed by the point (Pt. c 175m) notation. This hill was listed with a c 175m summit height and a 92m bwlch height, with these values giving this hill c 83m of drop and 47.43% dominance.

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

However, an adjoining hill named Town Hill on Ordnance Survey maps was also listed with a c 175m summit height. The summit of this hill is positioned at SS 639 939, and it was listed with c 47m of drop based on a c 128m bwlch height.

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

Since the original compilation of the Dominants list the summit heights of these two hills have been examined on the Ordnance Survey series of Six-Inch maps resulting in:

Pt. c 175m at SS 615 940: 574.0ft surface height

Town Hill at SS 639 939: 571ft levelled height

The above heights are relative to the Liverpool datum point and each have a loss of 0.4ft relative to the Newlyn Datum point. Therefore these heights are:

Pt. c 175m at SS 615 940: 573.6ft surface height (174.8m)

Town Hill at SS 639 939: 570.6ft levelled height (173.9m)

Extract from the Ordnance Survey series of Six-Inch maps

These values imply that the summit positioned at SS 615 940 is higher than the summit of Town Hill positioned at SS 639 939. However, LIDAR analysis gives a 175.6m height to Town Hill with this positioned at SS 63915 93921. LIDAR also gives a higher point on Town Hill; 175.8m at SS 63895 93893, this is in a back garden of a house and as aerial images suggest that this ground has been terra-formed it is being discounted from that of the height of the hill.

LIDAR does not cover the summit positioned at SS 615 940, therefore the best available evidence gives the following:

Pt. c 175m at SS 615 940: 174.8m (based on imperial surface height)

Town Hill at SS 639 939: 175.6m (based on LIDAR analysis)

The summit height produced by LIDAR analysis is 175.6m at SS 63915 93921 and its position in relation to that previously given comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

The summit height produced by LIDAR analysis is 175.6m and is positioned at SS 63915 93921, this position is not given a spot height on contemporary Ordnance Survey maps but is positioned within an uppermost 175m contour ring. This position is approximately 2.4 km east from where the 174.8m surface height appears on the Ordnance Survey Six-Inch map and where the old summit of the Dominant hill was once listed to.

The full details for the hill are:

Group: Mynydd Penlle’rcastell

Name: Town Hill

OS 1:50,000 map: 159

Summit Height: 175.6m (LIDAR)

Summit Grid Reference (new position): SS 63915 93921 (LIDAR)

Bwlch Height: 91.5m (LIDAR)

Bwlch Grid Reference: SS 65517 99306 (LIDAR)

Drop: 84.1m (LIDAR)

Dominance: 47.88% (LIDAR)

Myrddyn Phillips (January 2019)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Pwlldu Head (SS 569 865) - 12th summit relocation

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

LIDAR image of Pwlldu Head

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

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

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

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

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

LIDAR summit image of Pwlldu Head

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

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

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

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

The full details for the hill are:

Group: Gŵyr

Name: Pwlldu Head

OS 1:50,000 map: 159

Summit Height: 97.6m (LIDAR)

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

Bwlch Height: 62.2m (LIDAR)

Bwlch Grid Reference: SS 56191 88507 (LIDAR)

Drop: 35.5m (LIDAR)

Dominance: 36.32% (LIDAR)

Myrddyn Phillips (December 2018)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Broughton Burrows (SS 413 927) - 11th summit relocation

Significant Height Revisions post for Broughton Burrows

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

LIDAR image of Broughton Burrows

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

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

LIDAR image of Broughton Burrows showing the summit and connecting bwlch

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

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

Close up LIDAR summit image of Broughton Burrows

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

Extract from OS Maps

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

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

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

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

The full details for the hill are:

Group: Gŵyr

Name: Broughton Burrows

OS 1:50,000 map: 159

Summit Height: 61.9m (LIDAR)

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

Bwlch Height: 17.4m (LIDAR)

Bwlch Grid Reference: SS 41739 92663 (LIDAR)

Drop: 44.5m (LIDAR)

Dominance: 71.95% (LIDAR)

Myrddyn Phillips (December 2018)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Cae Uchaf (SS 575 943) - 10th summit relocation

Significant Name Changes post for Cae Uchaf

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, drop and status of the hill being confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR summit image of Cae Uchaf

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

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

The name of the bounded land where the summit of this hill is situated is Cae Uchaf and this was derived from the Tithe map, and it is the name that this hill is now listed by. The hill is adjoined to the Gŵyr group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C1), and it is positioned with the B 4296 road to its east, and has the small community of Y Crwys (Three Crosses) at its base to the west south-west.

If wanting to visit the hill permission to do so should be sought as the summit area is not a part of designated open access land, for those wishing to do so the nearest public footpath is to the north of the summit.

Prior to LIDAR analysis this hill was listed with 70m of drop and 48.61% dominance based on the 144m summit spot height and 74m bwlch spot height that appear on the Ordnance Survey 1:25,000 Explorer map.

LIDAR bwlch image of Cae Uchaf showing the natural bwlch to be intact

The summit height produced by 1m DTM LIDAR analysis is 144.4m at SS 57511 94397 and its position in relation to that previously given comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

The summit height produced by 1m DTM LIDAR analysis is 144.4m and is positioned at SS 57511 94397, this position is not given a spot height on contemporary Ordnance Survey maps and is approximately 65 metres west and in a different field from where the 144m spot height appears on the Ordnance Survey 1:25,000 Explorer map.

Ordnance Survey Interactive Coverage Map hosted on the Geograph website showing the summit position in relation to where the 144m spot height appears

The full details for the hill are:

Group: Gŵyr

Name: Cae Uchaf

OS 1:50,000 map: 159

Summit Height: 144.4m (LIDAR)

Summit Grid Reference (new position): SS 57511 94397 (LIDAR)

Bwlch Height: 73.4m (LIDAR, natural bwlch remains)

Bwlch Grid Reference: SS 50983 90868 (LIDAR)

Drop: 71.0m (LIDAR)

Dominance: 49.19% (LIDAR)

Myrddyn Phillips (November 2018)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Park Quarry (SN 428 120) - 9th summit relocation

Significant Name Changes post for Park Quarry

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

LIDAR image of Park Quarry

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

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

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

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

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

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

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

1m DTM LIDAR analysis gives the following:

Raised hedge bank: 93.999m at SN 42874 12092

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

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

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

The full details for the hill are:

Group: Mynydd Sylen

Name: Park Quarry

Summit Height: 93.9m (LIDAR)

OS 1:50,000 map: 159

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

Drop: 48.5m (LIDAR)

Dominance: 51.63% (LIDAR)

Myrddyn Phillips (November 2018)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Allt Cunedda (SN 407 090) - 8th 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 and position confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Allt Cunedda with the raised covered reservoir on bottom left and the summit of Allt Cunedda in the centre right

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

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

The name of the hill is Allt Cunedda and it is adjoined to the Mynydd Sylen group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C1), and is positioned with the stream valley of the Gwendraeth Fach and the A 484 road to the east, and has the small town of Cydweli (Kidwelly) towards the south.

As the summit of this hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so the nearest public footpath is to the south of the summit and relatively close to it.

Prior to LIDAR analysis this hill was listed with c 129m of drop based on the 192m summit spot height that is given to a triangulation pillar on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps and an estimated bwlch height of c 63m based on interpolation of bwlch contouring between 60m – 65m.

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website showing the summit position in relation to the trig pillar spot height position

The triangulation pillar is given a flush bracket height of 192.353m and is positioned at SN 40676 08999 and sits atop a concrete plinth that is approximately 0.15 – 0.2m high, and is positioned on grass at the base of a covered reservoir beside a concrete track giving access from a gate. The trig pillar seems to have been positioned on the hill before the construction of the covered reservoir and therefore in all likelihood is placed on natural ground. Therefore, dependent upon the accuracy of the flush bracket, the ground at the base of the trig pillar is approximately 191.8 - 191.9m in height.

The summit height produced by 1m DTM LIDAR analysis is 192.7m and is positioned at SN 40749 09013, this position is to the remains of a barrow that has been ploughed down to approximately 0.5m in height and which is situated in a field. This position is not given a spot height on Ordnance Survey maps and is approximately 75 metres east from where the previously listed summit position is situated.

The full details for the hill are:

Group: Mynydd Sylen

Name: Allt Cunedda

Summit Height: 192.7m (LIDAR)

OS 1:50,000 map: 159

Summit Grid Reference (New Position): SN 40749 09013 (LIDAR)

Drop: c 130m

Dominance: 67.30% (LIDAR)

Myrddyn Phillips (November 2018)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Castell y Garn (SM 880 212) - 7th summit relocation

There has been a Summit Relocation to a hill that appears in the Y Trechol – The Dominant Hills of Wales list, with the hill’s height, drop and dominance confirmed by LIDAR analysis conducted by Myrddyn Phillips.

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

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence equal or exceed half that of their absolute height. With the criteria for Lesser Dominant status being those addition Welsh P30 hills whose prominence is 33% or more and below 50% of their absolute height. The list is authored by Myrddyn Phillips and the Introduction to the Mapping Mountains publication of this list appeared on the 3^rd December 2015.

The name of the hill is Castell y Garn (Roch Castle in English) and it is adjoined to the Carn Llidi group of hills, which are situated in the south-western part of Mid and West Wales (Region B, Sub-Region B4), and is positioned with a minor road to its immediate south and the A 487 road to its south-west, and has the small community of Y Garn (Roch) towards the west.

As the summit of the hill is not on designated open access land permission to visit should be sought, for those wishing to do so the high point given by LIDAR analysis is to a rock outcrop that is beside a castle which functions as a hotel.

The summit location for this hill was originally given in the Dominant list to a 121m map heighted hill that has a triangulation pillar at its high point with a 122.685m flush bracket height and which is situated at SM 87859 16326. Since the initial compilation of this list was completed the Ordnance Survey Interactive Coverage Map hosted on the Geograph website has been made available online and this map gives a 122m summit spot height to the hill listed as Castell y Garn and therefore the summit location for the listed Dominant hill was transferred to the higher map heighted hill, and this summit relocation has now been confirmed by LIDAR analysis.

The summit height produced by 1m DTM LIDAR analysis is 122.8m and is positioned at SM 88048 21231, this position is given a 122m spot height on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website and is approximately 4.8km north from where the previously listed summit position is situated.

LIDAR image of Castell y Garn

The full details for the hill are:

Group: Carn Llidi

Name: Castell y Garn

Summit Height: 122.8m (LIDAR)

OS 1:50,000 map: 157

Summit Grid Reference (New Position): SM 88048 21231 (LIDAR)

Drop: 57.3m (LIDAR)

Dominance: 46.69% (LIDAR)

Myrddyn Phillips (September 2018)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Rhiw Gwraidd (SO 016 634) - 6th summit relocation

Survey post for Rhiw Gwraidd

There has been a Summit Relocation to a hill that is listed in the Y Pedwarau and Y Trechol – The Dominant Hills of Wales, with these details being retrospective as the line survey that initiated this summit relocation was conducted by John Barnard, Graham Jackson and Myrddyn Phillips on the 11^th June 2010, with the Trimble GeoXH 6000 survey that confirmed this hill’s height conducted by Myrddyn Phillips on the 2^nd January 2018.

The criteria for the two listings that this retrospective summit relocation affects are:

Y Pedwarau - Welsh hills at and above 400m and below 500m in height that have 30m minimum drop. The list is co-authored by Myrddyn Phillips and Aled Williams and the Introduction to the Mapping Mountains publication of this list appeared on the 30^th January 2017.

Y Trechol - The Dominant Hills of Wales - These are the Welsh P30 hills whose prominence equal or exceed half that of their absolute height. With the criteria for Lesser Dominant status being those addition Welsh P30 hills whose prominence is 33% or more and below 50% of their absolute height. The list is authored by Myrddyn Phillips and the Introduction to the Mapping Mountains publication of this list appeared on the 3^rd December 2015.

The name of the hill is Rhiw Gwraidd and it is situated in the Hirddywel range of hills which are in the northern part of Mid and West Wales (Region B, Sub-Region B1), and the hill is positioned between the A 44 road to its north and the A 470 road to its south-west, and has the town of Llandrindod to its east south-east.

Rhiw Gwraidd (SO 016 634)

As the summit of the hill is not on designated open access land permission to visit should be sought, for those wishing to do so a public footpath crests the ridge relatively near to this hill’s summit to the east.

When this hill was originally listed in the Welsh P30 lists on Geoff Crowder’s v-g.me website the summit position was given as SO 009 633, with an accompanying note stating Two tops of same height, other at SO 014 633. These two tops are given 442m spot heights on the Ordnance Survey 1:25,000 Explorer map, whilst a 440m ring contour further to the east is given a 441m spot height on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.

Rhiw Gwraidd

442m

SO009633

147

200

Marilyn. Clem/Yeaman. Two tops of same height, other at SO014633.

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

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

When this hill was line surveyed we found the summit position to be where the 440m ring contour is positioned on contemporary Ordnance Survey maps, however we did not survey the hill with the Leica equipment for its summit height and therefore the hill remained with a summit position corresponding to where the 441m spot height appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website and yet two 442m spot heights appear further to the west of this hill’s high point.

The line survey that determined the summit position of Rhiw Gwraidd

With the summit position established via the line survey it was an easy task to ascertain an accurate summit height for the hill with the Trimble GeoXH 6000, and therefore the position of the relocated summit from that given in the P30 lists on Geoff Crowder’s v-g.me website is at SO 01606 63432 and is the top of a small embedded rock that is approximately 1 metre north of a small cairn which is placed on featureless ground consisting of closely cropped grass, this position is given a spot height of 441m on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website and is approximately 650 metres east from where the summit position was originally given and 175 metres east north-east from where the second 442m spot height appears on the 1:25,000 Explorer map.

The full details for the hill are:

Group: Hirddywel

Summit Height: 441.7m (converted to OSGM15)

Name: Rhiw Gwraidd

OS 1:50,000 map: 147

Summit Grid Reference (New Position): SO 01606 63432

Drop: 212.1m (Trimble summit and LIDAR bwlch)

Dominance: 48.02% (Trimble summit and LIDAR bwlch)

The Trimble GeoXH 6000 gathering data at the summit of Rhiw Gwraidd with the old position of the summit in the background of this photograph

For details on the survey that added an accurate height to the relocated summit of his hill

Myrddyn Phillips (March 2018)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Upper Park (SJ 189 052) - 5th summit relocation

Survey post for Upper Park

Significant Height Revisions post for Upper Park

There has been confirmation of a Summit Relocation to a hill that is listed in the Y Trichant and Y Trechol – The Dominant Hills of Wales, and which was initiated by a survey with the Trimble GeoXH 6000, with the survey that confirmed this summit relocation taking place on the 7^th January 2018.

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

Y Trichant - Welsh hills at and above 300m and below 400m in height that have 30m minimum drop.

The name of the hill is Upper Park and it is situated in the Carnedd Wen range of hills which are in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is positioned between the A 458 road to its north and the A 483 road to its south-east, and has the town of Y Trallwng (Welshpool) to its north-east.

Upper Park (SJ 189 052)

As the summit of the hill is not on designated open access land and a part of a private estate permission to visit should be sought, for those wishing to do so there are a number of options for an ascent, all of which use tracks through forested plantations.

When this hill was originally listed in the Welsh P30 lists on Geoff Crowder’s v-g.me website the summit position was given as SJ 189 052, and although this six figure grid reference matches that of the position of the confirmed relocation, its position was to the 352m spot height that appears on the Ordnance Survey 1:25,000 Explorer map (SJ 18895 05292).

Two data sets were taken with the Trimble GeoXH 6000, the first at the high point of the hill which is in a deciduous plantation known as Crown Wood. The second was taken to the high point of the adjacent field where the 352m spot height appears, these results are given below:

1^st survey, inside Crown Wood at high point of hill: 354.0m (converted to OSGM15)

2^nd survey, adjacent field where the 352m spot height appears: 352.4m (converted to OSGM15)

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website showing the summit position in relation to the spot height position

Therefore, the confirmation of the position of the relocated summit is at SJ 18980 05270 and this is ground within a deciduous wood, this position is approximately 100 metres east south-eastward from where the 352m spot height appears on the Ordnance Survey 1:25,000 Explorer map.

The full details for the hill are:

Group: Carnedd Wen

Summit Height: 354.0m (converted to OSGM15)

Name: Upper Park

OS 1:50,000 map: 125

Summit Grid Reference (New Position): SJ 18980 05270

Drop: 177.0m (converted to OSGM15)

Dominance: 49.998%

The Trimble GeoXH 6000 gathering data at the summit of Upper Park with the position of where the 352m spot height appears on the ground in the frosted field in the centre background of this photo

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

Myrddyn Phillips (February 2018)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Bryn y Gwynt (SH 599 449) - 4th summit relocation

Hill Reclassifications post for Bryn y Gwynt

Significant Name Changes post for Bryn y Gwynt

Significant Height Revisions post for Bryn y Gwynt

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

LIDAR image of Bryn y Gwynt (SH 599 449)

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

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

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

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

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

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

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

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

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

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

The full details for the hill are:

Group: Moelwynion

Name: Bryn y Gwynt

OS 1:50,000 map: 124

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

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

Bwlch Height: 28.0m (LIDAR)

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

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

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

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

Myrddyn Phillips (February 2018)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Bryn Tŵr (SH 604 441) - 3rd summit relocation

Survey post for Bryn Tŵr

Significant Height Revisions post for Bryn Tŵr

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

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

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

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

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

Bryn Tŵr (SH 60453 44187)

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

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

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

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

The full details for the hill are:

Group: Moelwynion

Summit Height: 54.5m (converted to OSGM15)

Name: Bryn Tŵr

OS 1:50,000 map: 124

Summit Grid Reference (New Position): SH 60453 44187

Drop: c 43m

Dominance: 77.99%

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

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

Myrddyn Phillips (January 2018)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

Pen y Berth (SJ 081 127) - 2nd summit relocation

Summit survey post for Pen y Berth

Bwlch survey post for Pen y Berth

Significant Height Revisions post for Pen y Bwlch

There has been a Summit Relocation to the Y Trichant - The Dominant Hills of Wales list and also the 200m Twmpau (thirty welsh metre prominences and upward) list due to a survey with the Trimble GeoXH 6000, and these details are retrospective as the survey that resulted in this summit relocation was conducted on 19^th October 2014.

The survey was conducted in the hills just to the east of the small community of Dolanog, with the hill positioned above the B4382 which is to its south, and above the Afon Efyrnwy which is to its north.

The hill was surveyed in the company of Mark Trengove on a day when the westerly showers were being pushed east; thankfully all missed us as we visited two hills over two separate walks.

The hill is named Pen y Berth, and its prioritised summit position was listed at SJ 080 127 as this is where its 282m summit spot height appears on the Ordnance Survey enlarged mapping hosted on the Geograph website. This map also shows a twin 282m map heighted summit at SJ 083 127.

The position of the spot height at SJ 080 127 is immersed in a conifer plantation, whilst the position of the spot height at SJ 083 127 is on open ground with small deciduous trees growing near to it. The latter position was surveyed with the Trimble GeoXH 6000 as was a position on the periphery of the conifer plantation that was visually higher than the remaining ground within the forestry.

The result of each survey appears below:

282m spot height at SJ 083 127 came to 283.7m (converted to OSGM15) at SJ 08322 12748

new summit position came to 287.5m (converted to OSGM15) at SJ 08126 12730

282m spot height at SJ 080 127 was not surveyed as its position was deemed lower compared to the new summit position

The position of the relocated summit is at SJ 08126 12730 and is the top of featureless ground under Larch trees, this is not given a spot height on current Ordnance Survey maps but the Trimble result gave it as 5.5m higher and approximately 80 metres eastward from where the westerly 282m map spot height is positioned on the ground.

The full details for the hill are:

Cardinal Hill: Carreg y Big

Summit Height: 287.5m (converted to OSGM15)

Name: Pen y Berth

OS 1:50,000 map: 125

Summit Grid Reference (New Position): SJ 08126 12730

Drop: 134.2m (converted to OSGM15)

Dominance: 46.68%

The Trimble GeoXH 6000 set up at the new summit position of Pen y Berth, with the old position of the prioritised summit approximately 80 metres behind the Trimble and further into the conifer plantation

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

Myrddyn Phillips (October 2014)

Y Trechol - The Dominant Hills of Wales - Summit Relocations

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

Survey post for Graig Wen

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

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

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

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

The full details for the hill are:

Cardinal Hill: Mynydd Twr

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

Name: Graig Wen

OS 1:50,000 map: 114

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

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

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

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

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

Myrddyn Phillips (September 2014)

Sunday 17 September 2017

Mapping Mountains – Summit Relocations – Y Trechol –The Dominant Hills of Wales

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