Mapping Mountains – Hill Reclassifications – 100m Twmpau

 

Bryn y Beudy (SH 507 404) – 100m Sub-Twmpau addition

There has been confirmation of an addition to the list of 100m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Bryn y Beudy (SH 507 404)

The criteria for the list that this addition applies to are:

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

100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Bryn y Beudy and this was derived from the Tithe map, and it is adjoined to the Moel Hebog group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with minor roads to its north and south, the B4411 road to its south-west and the A487 road to its north-east, and has the town of Cricieth towards the south.

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with 22m of drop, based on the 156m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 134m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

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

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

Therefore, the confirmation of the addition of this hill to 100m Sub-Twmpau status is due to LIDAR analysis, resulting in a 155.2m summit height and a 132.7m bwlch height, with these values giving this hill 22.5m of drop, which is sufficient for it to be classified as a 100m Sub-Twmpau. 

 

The full details for the hill are: 

Group:  Moel Hebog 

Name:  Bryn y Beudy 

OS 1:50,000 map:  124

Summit Height:  155.2m (LIDAR) 

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

Bwlch Height:  132.7m (LIDAR) 

Bwlch Grid Reference:  SH 51229 40222 (LIDAR) 

Drop:  22.5m (LIDAR) 

 

Myrddyn Phillips (April 2024)

 

 

Mapping Mountains – Summit Relocations – 100m Twmpau and Y Trechol – The Dominant Hills of Wales

 

Coed Gaer (SH 799 808) 

There has been a Summit Relocation to a hill that is listed in the 100m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis conducted by Myrddyn Phillips. 

Coed Gaer (SH 799 808)

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

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

100m Twmpau by Myrddyn Phillips

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

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

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

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

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

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

However, it was not until the survey with the Trimble GeoXH 6000 that an accurate height could be ascertained for one of these points and not until LIDAR became available that the details for these two points could be re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR summit image of Coed Gaer (SH 799 808)

LIDAR analysis gives the highest ground close to the old prioritised summit as 131.1m positioned at SH 80216 80952, whilst the survey with the Trimble GeoXH 6000 gives the height of the recognised summit as 134.0m positioned at SH 79924 80840, and when compared to the original prioritised summit position this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

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

Therefore, the height produced by the Trimble GeoXH 6000 survey to the recognised summit is 134.0m and is positioned at SH 79924 80840, this position is given an uppermost 130m ring contour on the contemporary Ordnance Survey 1:25,000 Explorer map, and is approximately 290 metres south-westward from the position of the old prioritised summit. 

 

The full details for the hill are: 

Group:  Mynydd Hiraethog 

Name:  Coed Gaer 

OS 1:50,000 map:  115

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

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

Bwlch Height:  60.0m (LIDAR) 

Bwlch Grid Reference:  SH 81486 81889 (LIDAR) 

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

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

 

Myrddyn Phillips (April 2024)

 

 

Mapping Mountains – Hill Reclassifications – 30-99m Twmpau

Coed y Chwarel (SH 539 394) – 30-99m Sub-Twmpau addition 

There has been confirmation of an addition to the list of 30-99m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived by LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Coed y Chwarel (SH 539 394)

The criteria for the list that this addition applies to are:

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

30-99m Twmpau by Myrddyn Phillips

The name the hill is listed by is Coed y Chwarel, and it is adjoined to the Moel Hebog group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the A497 road to its north and a minor road to its east, and has the town of Porthmadog towards the east.

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

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 25m of drop, based on the 59m summit spot height that appears on the contemporary Ordnance Survey 1:25000 Explorer map, and an estimated c 34m bwlch height, based on interpolation of 5m contouring between 30m – 35m. 

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.

Therefore, the confirmation of the addition of this hill to 30-99m Sub-Twmpau status is due to LIDAR analysis, resulting in a 58.4m summit height and a 34.8m bwlch height, with these values giving this hill 23.6m of drop, which is sufficient for it to be classified as a 30-99m Sub-Twmpau. 

 

The full details for the hill are: 

Group:  Moel Hebog 

Name:  Coed y Chwarel 

OS 1:50,000 map:  124

Summit Height:  58.4m (LIDAR) 

Summit Grid Reference:  SH 53911 39499 (LIDAR)               

Bwlch Height:  34.8m (LIDAR) 

Bwlch Grid Reference:  SH 54045 39449 (LIDAR) 

Drop:  23.6m (LIDAR) 

 

Myrddyn Phillips (April 2024)

 

 

 

 

 

  

Mapping Mountains – Significant Name Changes – Y Trichant – The 300m Hills of Wales

 

Pt. 391.2m (SN 856 386) 

There has been a Significant Name Change to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Pt. 391.2m (SN 856 386)

The criteria for the list that this name change applies to are:

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 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, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The hill 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 and south, and the A483 road to its north-west, and has the town of Llanwrtyd towards the north north-east.

The hill appeared in the original 300m height band of Welsh P30 hills published on Geoff Crowder’s v-g.me website, under the invented and transposed name of Bryn Cefn Coch, with an accompanying note stating; Name from buildings to the North.

Bryn Cefn Coch

391m

SN857386

160

187

Height from 1985 1:50000 map. Name from buildings to the North

During my early hill listing I thought it appropriate to either invent a name for a hill, or use a name that appeared near to the summit of the hill on Ordnance Survey maps of the day.  My preference was to use farm names and put Pen, Bryn or Moel in front of them.  This is not a practice that I now advocate as with time and inclination place-name data can be improved either by asking local people or by examining historic documents, through this form of research an appropriate name for the hill can usually be found.

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

However, on occasion even when research is conducted an appropriate name for the hill may not be found, and on such occasions the listing protocol is to use the point (Pt. 391.2) notation, and for this hill this is such an example.

Therefore, the name this hill is now listed by in the Y Trichant – The 300m Hills of Wales is Pt. 391.2m, and this is being used as the author has not found an appropriate name for the hill either through historic research and/or local enquiry. 

 

The full details for the hill are: 

Group:  Mynydd Epynt 

Name:  Pt. 391.2m 

Previously Listed Name:  Bryn Cefn Coch 

OS 1:50,000 map:  160

Summit Height:  391.2m (LIDAR)                                                           

Summit Grid Reference:  SN 85642 38637 (LIDAR) 

Bwlch Height:  320.2m (LIDAR) 

Bwlch Grid Reference:  SN 86702 38910 (LIDAR) 

Drop:  71.0m (LIDAR) 

 

Myrddyn Phillips (April 2024)

                                                                        

  

Mapping Mountains – Summit Relocations – 200m Twmpau

Home Warren (SO 115 289) 

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)