Mapping Mountains – Summit Relocations – 200m Twmpau

 

200m Twmpau – Summit Relocations

The 200m Twmpau (thirty welsh metre prominences and upward) are the Welsh hills at or above 200m and below 300m in height that have a minimum drop of 30m.  Accompanying the main P30 list is a sub list entitled the 200m Sub-Twmpau with the qualification to 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.

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

Mapping Mountains - Summit Relocations - 200m Twmpau

Home Warren (SO 115 289) - 39th summit relocation

Significant Name Changes post for Home Warren

 

There has been a Summit Relocation to a hill that is listed in the 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Home Warren (SO 115 289)

The criteria for the list that this summit relocation applies to 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, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

200m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Home Warren and this was derived from the Tithe map, and it is adjoined to the Mynydd Epynt group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned encircled by minor roads, with the A470 road farther to its north-west, the A40 road farther to its south-west and the B4560 road farther to its east, and has the town of Aberhonddu (Brecon) towards the west.

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a 229m summit height, based on the spot height that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and which is positioned at SO 11597 28961. 

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

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with 33m of drop, based on the 229m summit spot height and the 196m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.

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

LIDAR analysis gives the highest ground on this hill as 229.5m positioned at SO 11570 28968.  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 Home Warren (SO 115 289)

The height produced by LIDAR analysis to the highest remaining natural ground of this hill is 229.3m positioned at SO 11574 28969 and SO 11573 28967, and this position in relation to the raised field boundary comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

Therefore, the summit height produced by LIDAR analysis is 229.3m and this is positioned at SO 11574 28969 and SO 11573 28967, this position is relatively close to where the 229m spot height appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 4 metres eastward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Mynydd Epynt 

Name:  Home Warren 

OS 1:50,000 map:  161

Summit Height:  229.3m (LIDAR) 

Summit Grid Reference (New Position):  SO 11574 28969 & SO 11573 28967 (LIDAR) 

Bwlch Height:  195.7m (LIDAR) 

Bwlch Grid Reference:  SO 10983 29324 (LIDAR) 

Drop:  33.6m (LIDAR) 

 

Myrddyn Phillips (April 2024)

 

Mapping Mountains - Summit Relocations - 200m Twmpau

Comin Gwauncaegurwen (SN 721 131) - 38th summit relocation

Hill Reclassifications post for Comin Gwauncaegurwen

Significant Height Revisions post for Comin Gwauncaegurwen

Significant Name Changes post for Comin Gwauncaegurwen

 

There has been a Summit Relocation to a hill that is listed in the 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail produced by JoeNuttall in his surface analysis programme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Myrddyn Phillips. 

LIDAR image of Comin Gwauncaegurwen (SN 721 131)

The criteria for the list that this summit relocation applies to 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, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

200m Twmpau by Myrddyn Phillips

The name the hill is listed by is Comin Gwauncaegurwen and this was derived from the Tithe map with the language protocol also used, 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 A4068 road to its north, the A4069 road to its west and a minor road to its south-west, and has the village of Brynaman towards the north-west.

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the main P30 list or the accompanying Hills to be surveyed sub list, as with no significant contours of note on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map it was difficult to judge whether any hill of note existed. 

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

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

Extract from the interactive mapping hosted on the WalkLakes website

One of the mapping resources now available online is the WalkLakes website which hosts an interactive map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available maps and a 258m spot height is given on the summit area of this hill.  Latterly the contemporary Ordnance Survey 1:25,000 Explorer map now has an uppermost 250m contour for this hill. 

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

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

LIDAR summit image of Comin Gwauncaegurwen (SN 721 131)

LIDAR analysis gives the highest ground on this hill as 258.43m positioned at SN 72184 13060.  However, this is a part of an edge of a raised section of track 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 analysis gives the highest ground on this hill that could now be deemed natural as 258.37m positioned at SN 72135 13154, and this position in relation to the raised edge of track 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 considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 258.4m and this is positioned at SN 72135 13154, 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 96 metres north-westward from where the edge of the raised track is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Du 

Name:  Comin Gwauncaegurwen 

OS 1:50,000 map:  160

Summit Height:  258.4m (LIDAR) 

Summit Grid Reference (New Position):  SN 72135 13154 (LIDAR) 

Bwlch Height:  218.5m (LIDAR) 

Bwlch Grid Reference:  SN 72505 12523 (LIDAR) 

Drop:  39.9m (LIDAR) 

 

Myrddyn Phillips (April 2024)

Mapping Mountains - Summit Relocations - 200m Twmpau

Mynydd Bach Brechfa (SN 520 286) - 37th summit relocation

Significant Height Revisions post for Mynydd Bach Brechfa

Significant Name Changes post for Mynydd Bach Brechfa

 

There has been a Summit Relocation to a hill that is listed in the 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail produced by Joe Nuttall in his surface analysis programme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Myrddyn Phillips. 

LIDAR image of Mynydd Bach Brechfa (SN 520 286)

The criteria for the list that this summit relocation applies to 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, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

200m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Mynydd Bach Brechfa and this was derived from the Ordnance Survey series of Six-Inch maps, and it is adjoined to the Mynydd Pencarreg group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned with the B4310 road to its north and west, and a minor road to its immediate south-east, and has the village of Brechfa towards the north north-east. 

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

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 category and listed with a 294m summit height, based on the spot height that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map at SN 52029 28578. 

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

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

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on other publicly available Ordnance Survey maps and for this hill it had 5m contouring, with the uppermost contour being 295m, resulting in an estimated c 297m summit height based on interpolation and a summit relocation to SN 51818 28761.

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 Mynydd Bach Brechfa (SN 520 286)

LIDAR analysis gives the highest natural ground on this hill as 296.1m positioned at SN 52039 28618, and this position in relation to the previously listed summit position 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 considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 296.1m and this is positioned at SN 52039 28618, 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 220 metres south-eastward from the previously listed summit position. 

 

The full details for the hill are: 

Group:  Mynydd Pencarreg 

Name:  Mynydd Bach Brechfa 

OS 1:50,000 map:  146

Summit Height:  296.1m (LIDAR) 

Summit Grid Reference (New Position):  SN 52039 28618 (LIDAR) 

Bwlch Height:  223.7m (LIDAR) 

Bwlch Grid Reference:  SN 51351 28147 (LIDAR) 

Drop:  72.3m (LIDAR) 

 

Myrddyn Phillips (March 2024)

Mapping Mountains - Summit Relocations - 200m Twmpau

Cae Cwar y Coed (SN 828 343) - 36th summit relocation

Significant Name Changes post for Cae Cwar y Coed

 

There has been a Summit Relocation to a hill that is listed in the 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Cae Cwar y Coed (SN 828 343)

The criteria for the list that this summit relocation applies to 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, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

200m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Cae Cwar y Coed and this was derived from the Tithe map, and it is adjoined to the Mynydd Epynt group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north-west and east, and the A40 road to its south, and has the town of Llanymddyfri (Llandovery) towards the west.

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a 248m summit height, based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map at SN 82773 34291.  This position was subsequently changed to SN 82761 34285, based on on-site visits and GPS data recorded on the Hill Bagging website. 

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

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

LIDAR summit image of Cae Cwar y Coed (SN 828 343)

LIDAR analysis gives the highest ground on this hill as 246.6m positioned at SN 82809 34336, and this position in relation to the previously listed summit position 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 considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 246.6m and this is positioned at SN 82809 34336, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 50 metres north-eastward from the previously listed summit position and importantly it is also positioned in a different field. 

 

The full details for the hill are: 

Group:  Mynydd Epynt 

Name:  Cae Cwar y Coed 

OS 1:50,000 map:  160

Summit Height:  246.6m (LIDAR) 

Summit Grid Reference (New Position):  SN 82809 34336 (LIDAR) 

Bwlch Height:  215.4m (LIDAR) 

Bwlch Grid Reference:  SN 83737 35272 (LIDAR) 

Drop:  31.2m (LIDAR) 

 

Myrddyn Phillips (March 2024)