200m Twmpau – Hill Reclassifications
The 200m Twmpau (thirty welsh metre prominences and upward) are the Welsh hills at or above 200m
and below 30om 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
additions, reclassifications and deletions to the main P30 list and the sub
list appear below presented chronologically in receding order.
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Moel Gallt y Cwm (SS 811 909) – 200m Sub-Twmpau reclassified to 200m Twmpau (35th reclassification)
There has been a reclassification to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill initially confirmed by Joe Nuttall who produced a summit analysis programme using LIDAR, and then by LIDAR analysis initially conducted by Jim Bloomer and subsequently by Myrddyn Phillips.
 |
| LIDAR image of Moel Gallt y Cwm (SS 811 909) |
The criteria for the list that this reclassification 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.
 |
| The 200m Twmpau by Myrddyn Phillips |
The name the hill is listed by is Moel Gallt y Cwm, and it is adjoined to the Cymoedd Morgannwg group of hills which are situated in the central part of South Wales (Region C, Sub-Region C2), and it is situated with the B4282 road to its north, the A4107 road to its west, the M4 motorway to its south-west and the A4063 road to its east, and has the town of Port Talbot 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 accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for the main P30 list.
When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimated c 24m of drop, based on the 272m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger map and an estimated c 248m bwlch height, based on interpolation of 10m contouring between 240m – 250m that appear on the Ordnance Survey 1:50,000 Landranger and 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 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 Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map. This mapping had many spot heights not on other publicly available Ordnance Survey maps, and for this hill it showed a 271m summit spot height and a 247m bwlch spot height, with these values giving this hill 24m of drop.
 |
| Extract from the Ordnance Survey 1:50,000 Landranger map |
However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The result produced by LIDAR analysis gives this hill 30.3m of drop. Therefore, the reclassification of this hill from 200m Sub-Twmpau status is due to LIDAR analysis, resulting in a 272.1m summit height and a 241.8m bwlch height, with these values giving this hill 30.3m of drop, which is sufficient for it to be classified as a 200m Twmpau.
The full details for the hill are:
Group: Cymoedd Morgannwg
Name: Moel Gallt y Cwm
OS 1:50,000 map: 170
Summit Height: 272.1m (LIDAR)
Summit Grid Reference: SS 81150 90920 (LIDAR)
Bwlch Height: 241.8m (LIDAR)
Bwlch Grid Reference: SS 81383 90910 (LIDAR)
Drop: 30.3m (LIDAR)
Myrddyn Phillips (December 2020)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Pastures (SJ 080 032) – 200m Sub-Twmpau addition (34th reclassification)
Significant Name Changes post for Pastures
There has been confirmation of an addition to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.
 |
| Pastures (SJ 080 032) |
The criteria for the list that this addition 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.
 |
| The 200m Twmpau by Myrddyn Phillips |
The name the hill is now listed by is Pastures and this was derived from local enquiry, and it is adjoined to the Carnedd Wen group of hills which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is encircled by minor roads, with the A458 road further to the north, the B4389 road further to the east and the A470 road further to the south-west, and has the small town of Llanfair Caereinion towards the north-east.
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 accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.
When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with 28m of drop, based on the 289m summit spot height and the 261m bwlch spot height that appear on the Ordnance Survey 1:25,000 Explorer map.
 |
| Extract from the Ordnance Survey 1:25,000 Explorer map |
However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
 |
| LIDAR image of Pastures |
The result produced by LIDAR analysis gives this hill 27.8m of drop, and 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 the Pastures |
Therefore, the confirmation of the addition of this hill to 200m Sub-Twmpau status is due to LIDAR analysis and a Trimble GeoXH 6000 survey, resulting in a 288.5m summit height and a 260.5m bwlch height, with these values giving this hill 27.9m of drop, which is sufficient for it to be classified as a 200m Sub-Twmpau.
The full details for the hill are:
Group: Carnedd Wen
Name: Pastures
OS 1:50,000 map: 136
Summit Height: 288.5m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SJ 08047 03297 (Trimble GeoXH 6000)
Bwlch Height: 260.5m (LIDAR)
Bwlch Grid Reference: SJ 07733 03319 (LIDAR)
Drop: 27.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Myrddyn Phillips (December 2020)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Square Field (SJ 070 031) – Trichant reclassified to 200m Twmpau (33rd reclassification)
There has been a reclassification to the list of Y Trichant – The 300m Hills of Wales and the 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.
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| Square Field (SJ 070 031) |
The criteria for the two listings that this reclassification 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 13th May 2017.
 |
| Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
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.
 |
| The 200m Twmpau by Myrddyn Phillips |
The name the hill is being listed by is Square Field and this was derived from local enquiry, and it is adjoined to the Carnedd Wen group of hills which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is encircled by minor roads, with also the A458 road to its north, the A470 road to its south-west and the B4389 road to its east, and has the village of Adfa towards the south south-west.
When the original 300m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list and listed with a 300m summit height, based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map.
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| 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 image of Square Field (SJ 070 031) |
The result produced by LIDAR analysis gives this hill a 299.4m summit height, and as the summit has now been surveyed with the Trimble GeoXH 6000 it is this result that is being prioritised for listing purposes.
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| The Trimble GeoXH 6000 gathering data at the summit of Square Field |
Therefore, the confirmation of the reclassification of this hill from Trichant status is due to LIDAR analysis and a Trimble GeoXH 6000 survey, resulting in 45.8m of drop, with a 299.4m summit height and a 253.6m bwlch height, with the summit height insufficient for Trichant status the therefore the hill is reclassified to a 200m Twmpau
The full details for the hill are:
Group: Carnedd Wen
Name: Square Field
OS 1:50,000 map: 136
Summit Height: 299.4m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SJ 07034 03161 (Trimble GeoXH 6000)
Bwlch Height: 253.6m (LIDAR)
Bwlch Grid Reference: SJ 06533 03161 (LIDAR)
Drop: 45.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Myrddyn Phillips (November 2020)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Cae Top (SJ 061 016) – 200m Sub-Twmpau addition (32nd reclassification)
There has been confirmation of an addition to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.
 |
| Cae Top (SJ 061 016) |
The criteria for the list that this addition 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.
 |
| The 200m Twmpau by Myrddyn Phillips |
The name the hill is now listed by is Cae Top and this was derived from the Tithe map, and it is adjoined to the Carnedd Wen group of hills which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is encircled by minor roads, with also the B4389 and B4390 roads to its east, and has the village of Adfa towards the south.
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 accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.
 |
| 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 26m of drop, based on the 269m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and which is now presented on the mapping on the Magic Maps website, and the 243m bwlch spot height that appears on the Ordnance Survey 1:25,000 Explorer map.
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| Extract from the Magic Maps website |
However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
 |
| LIDAR image of Cae Top |
The result produced by LIDAR analysis gives this hill 25.7m of drop, and 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 Cae Top |
Therefore, the confirmation of the addition of this hill to 200m Sub-Twmpau status is due to LIDAR analysis and a Trimble GeoXH 6000 survey, resulting in a 268.8m summit height and a 243.0m bwlch height, with these values giving this hill 25.9m of drop, which is sufficient for it to be classified as a 200m Sub-Twmpau.
The full details for the hill are:
Group: Carnedd Wen
Name: Cae Top
OS 1:50,000 map: 136
Summit Height: 268.8m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SJ 06132 01671 (Trimble GeoXH 6000)
Bwlch Height: 243.0m (LIDAR)
Bwlch Grid Reference: SJ 06613 01642 (LIDAR)
Drop: 25.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Myrddyn Phillips (November 2020)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Cae Cefn Tŷ (SN 416 535) – 200m Sub-Twmpau reclassified to 200m Twmpau (31st reclassification)
There has been a reclassification to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary and historical maps produced from Ordnance Survey data. This was initiated by Joe Nuttall who produced a summit analysis programme, and then by evaluation conducted by Jim Bloomer and subsequently by Myrddyn Phillips.
The criteria for the list that this reclassification 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.
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| The 200m Twmpau by Myrddyn Phillips |
The name the hill is now listed by is Cae Cefn Tŷ and this was derived from the Tithe map, and it is adjoined to the Hafod Ithel group of hills which are situated in the western part of Mid and West Wales (Region B, Sub-Region B2), and it has the A487 road to its north-west, the B4338 road to its south-west and minor roads to its south-east and its north-east, and has the town of Ceinewydd (New Quay) towards the north 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 accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.
When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimated c 25m of drop, based on the 289m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 264m bwlch height, with the latter based on interpolation of 5m contouring between 260m – 265m.
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| Extract from the Ordnance Survey 1:25,000 Explorer map |
The Ordnance Survey 1:25,000 Explorer map shows Cae Cefn Tŷ to be a twin 289m map heighted hill along with its adjacent hill of Moel Rhydeinon (SN 427 542), which for listing purposes was prioritised for the main summit and therefore the lowest connecting bwlch, due to it having a triangulation pillar on its summit area and an OS Bolt given the height of 290.254m in the OS Trig Database that appear as B/Bolt POSS OK. This Database also reports that the trig station was removed by the farmer.
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 old Vector Map Local that used to be hosted on the Geograph website and which was entitled the Interactive Coverage Map, and it is the series of Six-Inch maps and the Historical 1:25,000 map that shows an imperial height of 953ft (290.48m) for Cae Cefn Tŷ and a 951ft (289.87m) height for Moel Rhydeinon. These summit heights resulted in the swapping of the bwlch positions.
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| Extract from the Ordnance Survey Historical 1:25,000 map |
The details for this hill were also re-assessed against the mapping on the OS Maps website. This is the replacement for OS Get-a-map and until recent times had contours at 5m intervals which were proving consistently more accurate compared to the 5m contours that sometimes appear on the Ordnance Survey 1:25,000 Explorer map and used to appear on the online Vector Map Local. The contouring on this mapping did not match that on the Ordnance Survey 1:25,000 Explorer map, but it is being prioritised for this hill and resulted in its bwlch height being listed as an estimated c 258m based on interpolation of 5m contouring between 255m – 260m.
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| Extract from the OS Maps website |
Therefore, the reclassification of this hill from 200m Sub-Twmpau status is due to detail on contemporary and historical maps produced from Ordnance Survey data, resulting in a 290m summit height and an estimated c 258m bwlch height, with these values giving this hill an estimated c 32m of drop, which is sufficient for it to be classified as a 200m Twmpau.
The full details for the hill are:
Group: Hafod Ithel
Name: Cae Cefn Tŷ
OS 1:50,000 map: 146
Summit Height: 290m (spot height)
Summit Grid Reference: SN 41694 53513 (hand-held GPS via DoBIH)
Bwlch Height: c 258m (interpolation)
Bwlch Grid Reference: SN 40762 52700 (interpolation)
Drop: c 32m (spot height summit and interpolated bwlch)
Myrddyn Phillips (November 2020)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Cae Clofar Bach (SJ 069 007) – 200m Sub-Twmpau addition (30th reclassification)
There has been confirmation of an addition to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.
 |
| Cae Clofar Bach (SJ 069 007) |
The criteria for the list that this addition 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.
 |
| The 200m Twmpau by Myrddyn Phillips |
The name the hill is now listed by is Cae Clofar Bach and this was derived from the Tithe map, and it is adjoined to the Carnedd Wen group of hills which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is encircled by minor roads, with farther afield the B4389 and B4390 roads to its east, and has the village of Adfa towards the west 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 accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.
When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimated c 23m of drop, based on the 247m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 224m bwlch height, with the latter based on interpolation of 5m contouring between 220m – 225m.
 |
| 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 image of Cae Clofar Bach |
The result produced by LIDAR analysis gives this hill 21.7m of drop, and as the summit has now been surveyed with the Trimble GeoXH 6000 it is this result that is being prioritised for listing purposes.
 |
| The Trimnle GeoXH 6000 gathering data at the summit of Cae Clofar Bach |
Therefore, the confirmation of the addition of this hill to 200m Sub-Twmpau status is due to LIDAR analysis and a Trimble GeoXH 6000 survey, resulting in a 246.1m summit height and a 224.3m bwlch height, with these values giving this hill 21.8m of drop, which is sufficient for it to be classified as a 200m Sub-Twmpau.
The full details for the hill are:
Group: Carnedd Wen
Name: Cae Clofar Bach
OS 1:50,000 map: 136
Summit Height: 246.1m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SJ 06945 00724 (Trimble GeoXH 6000)
Bwlch Height: 224.3m (LIDAR)
Bwlch Grid Reference: SJ 06767 00923 (LIDAR)
Drop: 21.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Crasty Frain (SO 109 983) – 200m Sub-Twmpau reclassified to 200m Twmpau (29th reclassification)
There has been confirmation of a reclassification to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill initially confirmed by LIDAR analysis instigated by Joe Nuttall who produced a summit analysis programme, and then by LIDAR analysis conducted initially by Jim Bloomer and subsequently by Myrddyn Phillips, with the summit later surveyed with the Trimble GeoXH 6000 and which was conducted by Myrddyn Phillips.
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| Crasty Frain (SO 109 983) |
The criteria for the list that this reclassification 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.
 |
| The 200m Twmpau by Myrddyn Phillips |
The name the hill is now listed by is Crasty Frain and this was derived from the Tithe map, and it is adjoined to the Carnedd Wen group of hills which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is positioned with a minor road to its north and the B4389 road to its south-west, and has the village of Tregynon towards the west 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 included in the accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for the main P30 list.
When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimated c 27m of drop, based on the 253m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 226m bwlch height, with the latter based on interpolation of 10m contouring between 220m – 230m.
 |
| Extract from the Ordnance Survey 1:25,000 Explorer map |
However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The reclassification of this hill was initiated by Joe Nuttall who produced a summit analysis programme that used LIDAR with analternative height map (DEM) allowing identification of summits and cols and thereby drops. The resulting spreadsheet that Joe produced contains over 29,600 hills.
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| LIDAR image of Crasty Frain |
This spreadsheet is being evaluated by a number of people, and for this particular hill it was Jim Bloomer who initially assessed this hill’s data against that produced via LIDAR. Myrddyn Phillips then evaluated the details for this hill via LIDAR analysis and confirmed its height and drop and hence its reclassification to 200m Twmpau status. The summit of this hill has now been surveyed with the Trimble GeoXH 6000 and it is this evaluation on the hill and the subsequent survey that is being prioritised.
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| The Trimble GeoXH 6000 gathering data at the summit of Crasty Frain |
Therefore, the confirmation of the reclassification of this hill from 200m Sub-Twmpau status is due to LIDAR analysis and a Trimble GeoXH 6000 survey, resulting in a 256.3m summit height and a 226.1m bwlch height, with these values giving this hill 30.2m of drop, which is sufficient for it to be classified as a 200m Twmpau.
The full details for the hill are:
Group: Carnedd Wen
Name: Crasty Frain
OS 1:50,000 map: 136
Summit Height: 256.3m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SO 10995 98318 (Trimble GeoXH 6000)
Bwlch Height: 226.1m (LIDAR)
Bwlch Grid Reference: SO 10787 98754 (LIDAR)
Drop: 30.2m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Myrddyn Phillips (October 2020)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Church Hill Common (SO 51785 10565 & SO 51788 10566) – 200m Sub-Twmpau reclassified to 200m Twmpau (28th reclassification)
Significant Name Changes post for Church Hill Common
Summit Relocations post for Church Hill Common
Church Hill Common (SO 51785 10565 & SO 51788 10566) – 200m Sub-Twmpau reclassified to 200m Twmpau (28th reclassification)
Significant Name Changes post for Church Hill Common
Summit Relocations post for Church Hill Common
There has been confirmation of a reclassification to the list of 200m Twmpau, 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 Church Hill Common (SO 517 105) |
The criteria for the list that this reclassification 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.
The name the hill is listed by is Church Hill Common, and it is adjoined to the Gwent Is Coed group of hills which are situated in the south-eastern part of South Wales (Region C, Sub-Region C3), and it is positioned with the B4293 road and the A40 road to the west and the A466 road and the Afon Gwy (River Wye) to the east, and has the town of Trefynwy (Mounmouth) 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 included in the accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for the main P30 list.
When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimated c 30m of drop, based on the 232m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 202m bwlch height, with the latter based on interpolation of 5m contouring between 200m – 205m.
 |
| 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 image of Church Hill Common |
The confirmation of the reclassification of this hill from 200m Sub-Twmpau status is due to LIDAR analysis, resulting in a 232.7m summit height and a 202.3m bwlch height, with these values giving this hill 30.3m of drop, which is sufficient for it to be classified as a 200m Twmpau.
The full details for the hill are:
Group: Gwent Is Coed
Name: Church Hill Common
OS 1:50,000 map: 162
Summit Height: 232.7m (LIDAR)
Summit Grid Reference: SO 51785 10565 & SO 51788 10566 (LIDAR)
Bwlch Height: 202.3m (LIDAR)
Bwlch Grid Reference: SO 51524 10349 (LIDAR)
Drop: 30.3m (LIDAR)
Myrddyn Phillips (May 2020)
Pt. 277.3m (ST 485 990) – 200m Sub-Twmpau reclassified to 200m Twmpau (27th reclassification)
There has been confirmation of a reclassification to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.
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| LIDAR image of Pt. 277.3m (ST 485 990) |
The criteria for the list that this reclassification 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.
The hill is being listed by the point (Pt. 277.3m) notation as an appropriate name for it either through local enquiry and / or historic research has not been found by the author, and it is adjoined to the Gwent Is Coed group of hills which are situated in the south-eastern part of South Wales (Region C, Sub-Region C3), and it is positioned with the B4293 road to its west, and has the village of Y Dyfawden (Devauden) towards the south-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 accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for the main P30 list.
When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimated c 30m of drop, based on the 277m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated c 247m bwlch height, with the latter based on interpolation of 5m contouring between 245m – 250m.
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| Extract from the Ordnance Survey 1:25,000 Explorer map |
However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The confirmation of the reclassification of this hill from 200m Sub-Twmpau status is due to LIDAR analysis, resulting in a 277.3m summit height and a 246.3m bwlch height, with these values giving this hill 31.0m of drop, which is sufficient for it to be classified as a 200m Twmpau.
The full details for the hill are:
Group: Gwent Is Coed
Name: Pt. 277.3m
OS 1:50,000 map: 171
Summit Height: 277.3m (LIDAR)
Summit Grid Reference: ST 48569 99063 (LIDAR)
Bwlch Height: 246.3m (LIDAR)
Bwlch Grid Reference: ST 48475 98819 (LIDAR)
Drop: 31.0m (LIDAR)
Myrddyn Phillips (May 2020)
Coed y Bwnydd (SO 366 069) – 100m Twmpau reclassified to 200m Twmpau (26th reclassification)
Significant Name Changes post for Coed y Bwnydd
Summit Relocations post for Coed y Bwnydd
Significant Height Revisions post for Coed y Bwnydd
There has been a reclassification to the list of 100m Twmpau and 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.
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| LIDAR image of Coed y Bwnydd (SO 366 069) |
The criteria for the two listings that this reclassification 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.
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| 100m Twmpau by Myrddyn Phillips |
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.
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| 200m Twmpau 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.
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| 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.
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| Extract from the Magic Maps website |
However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The reclassification of this hill from 100m Twmpau status is due to LIDAR analysis, resulting in a 201.4m summit height and a 59.4m bwlch height, with these values giving this hill 142.0m of drop. With the 201.4m summit height taken to the remains of an embankment which forms a part of an ancient hill fort which qualifies under the criteria used within this list and its height is sufficient for it to be classified as a 200m Twmpau.
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: SO 36613 06919 (LIDAR)
Bwlch Height: 59.4m (LIDAR)
Bwlch Grid Reference: SO 39308 08901 (LIDAR)
Drop: 142.0m (LIDAR)
Myrddyn Phillips (January 2020)
Penmaen Bach (SH 750 777) – 200m Sub-Twmpau addition (25th reclassification)
There has been confirmation of an addition to the 200m Twmpau list, with the summit height and its location, the drop and status of the hill initially confirmed by LIDAR analysis and subsequently by a survey with the Trimble GeoXH 6000 which were conducted by Myrddyn Phillips, with the latter taking place on the 15th October 2018.
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| Penmaen Bach (SH 750 777) |
The criteria for the list that this hill reclassification 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 category entitled the 200m Sub-Twmpau consisting of all Welsh hills at or above 200m and below 300m in height that have 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 Penmaen Bach 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 it is positioned with the A55 road and the coast to its north, and has the town of Conwy towards the east.
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 Hills to be surveyed sub list as it did not meet the criteria then used in this list, however this sub list has now been standardised and interpolated heights and drop values also included in the main P30 and the accompanying sub list.
After this list was standardised and interpolated heights also included the details for the hill 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.
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| The Ordnance Survey Vector Map Local hosted on the Geograph website which is entitled the Interactive Coverage Map |
When the details for this hill were re-assessed it was listed with an estimated c 23m of drop, based on an estimated c 236m summit height and an estimated c 213m bwlch height, with each based on interpolation of 5m contouring on the Ordnance Survey Vector Map Local.
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.
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| LIDAR image of Penmaen Bach |
The confirmation of the addition of Penmaen Bach to 200m Sub-Twmpau status is due to LIDAR analysis and a subsequent survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, resulting in a 235.4m summit height and a 208.3m bwlch height, with these values giving this hill 27.1m of drop which is sufficient for it to be classified as a 200m Sub-Twmpau.
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| The Trimble GeoXH 6000 gathering data at the summit of Penmaen Bach |
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| The Trimble GeoXH 6000 gathering data at the bwlch of Penmaen Bach |
The full details for the hill are:
Group: Carneddau
Name: Penmaen Bach
OS 1:50,000 map: 115
Summit Height: 235.4m (converted to OSGM15)
Summit Grid Reference: SH 75005 77770
Bwlch Height: 208.3m (converted to OSGM15)
Bwlch Grid Reference: SH 74888 77897
Drop: 27.1m
Myrddyn Phillips (April 2019)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Mountain Park (SN 171 120) – 200m Sub-Twmpau reclassified to 200m Twmpau (24th reclassification)
Survey post for Mountain Park
Significant Name Changes post for Mountain Park
There has been confirmation of an addition to the 200m Twmpau list due to LIDAR analysis and a subsequent summit survey using the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the criteria for this list being:
200m Twmpau – Welsh hills at or above 200m and below 300m in height that have 30m minimum drop, with an accompanying sub category entitled the 200m Sub-Twmpau consisting of all Welsh hills at or above 200m and below 300m in height that have 20m or more and below 30m of drop. With the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
Prior to LIDAR analysis this hill was listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website, and after this sub list was standardised with interpolated heights and drop values also included it was initially listed with an estimated c 30m of drop based on an estimated summit height of c 203m and a bwlch height of 173m based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map. The summit height for this hill was then revised to 204m based on the spot height that appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website, with this new value giving this hill 31m of drop.
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| Extract from the Ordnance Survey 1:25,000 Explorer map |
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| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
The land where the summit of this hill is situated is given the name of Mountain Park on the Tithe map and the hill is adjoined to the Brandy Hill 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 the B 4328 road to its north and has the small community of Tafarn Ysbyty (Tavernspite) towards the north-west.
As the summit of the hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so access from a minor road to the south will probably be the most convenient for an ascent.
The confirmation of this hill’s reclassification to 200m Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
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| LIDAR image of the summit of Mountain Park |
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| LIDAR image of the bwlch of Mountain Park |
The 2m DTM LIDAR analysis gives the hill the following details:
Name: Mountain Park
Summit Height: 203.8m
Summit Grid Reference: SN 17181 12032
Bwlch Height: 173.5m
Bwlch Grid Reference: SN 15693 11421
Drop: 30.3m
Therefore, the 203.8m LIDAR analysis for the summit position at SN 17181 12032 and the 173.5m LIDAR analysis for the bwlch position at SN 15693 11421 gives this hill 30.3m of drop, which is sufficient for it to be classified as a 200m Twmpau, with the details from the Trimble GeoXH 6000 survey being 203.7m (converted to OSGM15) summit at SN 17181 12029, giving this hill 30.3m of drop.
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| LIDAR image of Mountain Park |
The full details for the hill are:
Group: Brandy Hill
Name: Mountain Park
OS 1:50,000 map: 158
Summit Height: 203.7m (converted to OSGM15)
Summit Grid Reference: SN 17181 12029
Bwlch Height: 173.5m (LIDAR)
Bwlch Grid Reference: SN 15693 11421 (LIDAR)
Drop: 30.3m (Trimble summit and LIDAR bwlch)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Foel Tyddyn y Berllan (SH 634 051) – 200m Sub-Twmpau reclassified to 200m Twmpau (23rd reclassification)
Survey post for Foel Tyddyn y Berllan
Significant Name Changes post for Foel Tyddyn y Berllan
There has been a reclassification to the listing of 200m Twmpau due to LIDAR analysis conducted by Myrddyn Phillips and subsequently confirmed via a survey with the Trimble GeoXH 6000 which took place on the 14.05.18, with the criteria for this list being:
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.
Prior to LIDAR analysis this hill was listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website, and after this sub list was standardised with interpolated heights and drop values also included it was initially listed with an estimated c 31m of drop and later changed to 28m of drop, based on the 233m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 205m bwlch spot height that appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.
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| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
The locally known name of the hill is Foel Tyddyn y Berllan and it is adjoined to the Tarennydd range of hills which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and it overlooks the Dyffryn Dysynni to its north-west, and has the small community of Anertrinant towards its east and Bryn-crug towards its south-west.
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| Foel Tyddyn y Berllan (SH 634 051) |
As the summit of the 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 towards the east of the summit can gain the eastern ridge of the adjacent hill which is positioned towards the south, and from here it is only a short distance to the summit of this hill.
The reclassification of Foel Tyddyn y Berllan to 200m Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
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| LIDAR image of Foel Tyddyn y Berllan |
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Foel Tyddyn y Berllan
Summit Height: 232.3m
Summit Grid Reference: SH 63480 05160
Bwlch Height: 200.5m
Bwlch Grid Reference: SH 63493 04962
Drop: 31.8m
Therefore, the 232.3m LIDAR analysis for the summit position at SH 63480 05160 and the 200.5m LIDAR analysis for the bwlch position at SH 63493 04962 gives this hill 31.8m of drop, which is sufficient for it to be classified as a 200m Twmpau, with the details from the Trimble GeoXH 6000 survey being 232.8m (converted to OSGM15) summit at SH 63481 05158 and 200.3m (converted to OSGM15) bwlch at SH 63494 04961, giving this hill 32.5m of drop.
The full details for the hill are:
Group: Tarennydd
Name: Foel Tyddyn y Berllan
OS 1:50,000 map: 124
Summit Height: 232.8m (converted to OSGM15)
Summit Grid Reference: SH 63481 05158
Bwlch Height: 200.3m (converted t0 OSGM15)
Bwlch Grid Reference: SH 63494 04961
Drop: 32.5m
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| The Trimble GeoXH 6000 gathering data at the summit of Foel Tyddyn y Berllan |
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Foel (SH 632 045) – 200m Sub-Twmpau reclassified to 200m Twmpau (22nd reclassification)
Survey post for Foel
Significant Name Changes post for Foel
There has been a reclassification to the listing of 200m Twmpau due to LIDAR analysis conducted by Myrddyn Phillips and subsequently confirmed via a survey with the Trimble GeoXH 6000 which took place on the 14.05.18, with the criteria for this list being:
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.
Prior to LIDAR analysis this hill was listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website, and after this sub list was standardised with interpolated heights and drop values also included it was initially listed with an estimated c 31m of drop and later changed to 29m of drop, based on the 288m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 259m bwlch spot height that appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.
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| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
The locally known name of the hill is Foel and it is adjoined to the Tarennydd range of hills which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and it overlooks the B 4405 road and the Afon Fathew to the south-east and the Afon Dysynni to the north-west, and has the small community of Dolgoch to its east and Bryn-crug to its south-west.
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| Foel (SH 632 045) |
As the summit of the 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 to the south and east of the summit can gain the eastern ridge of the hill or this can also be gained using a green track that makes its way up toward this ridge.
The reclassification of Foel to 200m Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
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| LIDAR image of Foel |
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Foel
Summit Height: 288.2m
Summit Grid Reference: SH 63297 04584
Bwlch Height: 257.7m
Bwlch Grid Reference: SH 62972 04434
Drop: 30.5m
Therefore, the 288.2m LIDAR analysis for the summit position at SH 63297 04584 and the 257.7m LIDAR analysis for the bwlch position at SH 62972 04434 gives this hill 30.5m of drop, which is sufficient for it to be classified as a 200m Twmpau, with the details from the Trimble GeoXH 6000 survey being 288.3m (converted to OSGM15) summit at SH 63297 04583 and 257.7m (converted to OSGM15) bwlch at SH 62971 04432, giving this hill 30.6m of drop.
The full details for the hill are:
Group: Tarennydd
Name: Foel
OS 1:50,000 map: 135
Summit Height: 288.3m (converted to OSGM15)
Summit Grid Reference: SH 63297 04583
Bwlch Height: 257.7m (converted to OSGM15)
Bwlch Grid Reference: SH 62971 04432
Drop: 30.6m
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| The Trimble GeoXH 6000 gathering data at the summit of Foel |
Myrddyn Phillips (July 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Pt. 232.1m (SH 675 157) – 200m Sub-Twmpau addition (21st reclassification)
There has been an addition to the 200m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:
200m Twmpau - Welsh hills at and 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 and 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.
Prior to LIDAR analysis this hill was listed with 18m of drop based on the 233m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 215m bwlch spot height that appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.
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| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
As the name of this hill has not been confirmed by the author the hill is being listed by the point (Pt. 232.1m) notation and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and the hill is positioned with the A 493 road to its north-west and has the town of Dolgellau towards its east north-east.
The summit of the hill is a part of designated open access land with the most probable and convenient access to the hill via a public footpath approaching this land from a minor road towards the south-west of the summit.
The addition of this hill to 200m Sub-Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Pt. 232.1m
Summit Height: 232.1m
Summit Grid Reference: SH 67577 15753
Bwlch Height: 210.0m
Bwlch Grid Reference: SH 67357 15854
Drop: 22.1m
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| LIDAR image of Pt. 232.1m |
Therefore, the 232.1m LIDAR analysis for the summit position at SH 67577 15753 and the 210.0m LIDAR analysis for the bwlch position at SH 67357 15854 gives this hill 22.1m of drop, which is sufficient for it to be classified as a 200m Sub-Twmpau.
The full details for the hill are:
Group: Cadair Idris
Name: Pt. 232.1m
OS 1:50,000 map: 124
Summit Height: 232.1m (LIDAR)
Summit Grid Reference: SH 67577 15753 (LIDAR)
Bwlch Height: 210.0m (LIDAR)
Bwlch Grid Reference: SH 67357 15854 (LIDAR)
Drop: 22.1m (LIDAR)
Myrddyn Phillips (June 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Pt. 252.3m (SH 697 167) – 200m Sub-Twmpau addition (20th reclassification)
There has been an addition to the 200m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:
200m Twmpau - Welsh hills at and 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 and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
Prior to LIDAR analysis this hill was listed with c 19m of drop based on the 252m summit spot height that appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website and an estimated bwlch height of c 233m based on bwlch contouring between 230m – 240m.
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| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
As the name of the ffridd taking in this hill’s summit has not been confirmed the hill is being listed by the point (Pt. 252.3m) notation and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and the hill is positioned with the A 493 road to its north and has the town of Dolgellau towards its east north-east.
As the hill is a part of designated open access land the summit can be approached from a number of directions, with a bridleway to the south of the hill probably giving easiest access.
The addition of this hill to 200m Sub-Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Pt. 252.3m
Summit Height: 252.3m
Summit Grid Reference: SH 69722 16736
Bwlch Height: 232.05m
Bwlch Grid Reference: SH 69739 16620 & SH 69730 16624 & SH 69732 16628
Drop: 20.2m
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| LIDAR image of Pt. 252.3m |
Therefore, the 252.3m LIDAR analysis for the summit position at SH 69722 16736 and the 232.05m LIDAR analysis for the bwlch position at SH 69739 16620 and SH 69730 16624 and SH 69732 16628 gives this hill 20.2m of drop, which confirms its addition to 200m Sub-Twmpau status.
The full details for the hill are:
Group: Cadair Idris
Name: Pt. 252.3m
OS 1:50,000 map: 124
Summit Height: 252.3m (LIDAR)
Summit Grid Reference: SH 69722 16736 (LIDAR)
Bwlch Height: 232.05m (LIDAR)
Bwlch Grid Reference: SH 69739 16620 & SH 69730 16624 & SH 69732 16628 (LIDAR)
Drop: 20.2m (LIDAR)
Myrddyn Phillips (June 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Pt. 254.9m (SH 690 175) – 200m Sub-Twmpau addition (19th reclassification)
There has been confirmation of an addition to the 200m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:
200m Twmpau - Welsh hills at and 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 and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
This hill was not listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website as it did not meet the criteria then used for this category of hill; however this list has now been standardised and interpolated heights and drop values also included, resulting in this hill being listed with c 22m of drop, based on the 256m summit spot height that appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website and an estimated bwlch height of c 234m based on bwlch contouring between 230m – 240m.
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| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
As the name of the ffridd taking in this hill’s summit has not been confirmed the hill is being listed by the point (Pt. 254.9m) notation and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and the hill is positioned with the A 493 road to its north and has the town of Dolgellau towards its east.
As the 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 crosses to the south of the summit and this can be accessed from open access land to the west.
The confirmation of the addition of this hill to 200m Sub-Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Pt. 254.9m
Summit Height: 254.9m
Summit Grid Reference: SH 69086 17596
Bwlch Height: 231.5m
Bwlch Grid Reference: SH 68969 17478
Drop: 23.5m
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| LIDAR image of Pt. 254.9m |
Therefore, the 254.9m LIDAR analysis for the summit position at SH 69086 17596 and the 231.5m LIDAR analysis for the bwlch position at SH 68969 17478 gives this hill 23.5m of drop, which confirms its addition to 200m Sub-Twmpau status.
The full details for the hill are:
Group: Cadair Idris
Name: Pt. 254.9m
OS 1:50,000 map: 124
Summit Height: 254.9m (LIDAR)
Summit Grid Reference: SH 69086 17596 (LIDAR)
Bwlch Height: 231.5m (LIDAR)
Bwlch Grid Reference: SH 68969 17478 (LIDAR)
Drop: 23.5m (LIDAR)
Myrddyn Phillips (June 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Tŵr Glas (SH 672 164) – 200m Sub-Twmpau reclassified to 200m Twmpau (18th reclassification)
There has been confirmation of a reclassification to the 200m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:
200m Twmpau - Welsh hills at and 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 and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
This hill was listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website as it did not meet the criteria then used for the main P30 list; however this list has now been standardised and interpolated heights and drop values also included, resulting in this hill being listed with an estimated c 30m of drop, based on the 227m summit spot height that appears on Harvey maps and an estimated bwlch height of c 197m based on bwlch contouring between 190m – 200m. The details for this hill were later amended when the Ordnance Survey Interactive Coverage Map hosted on the Geograph website became available online and it was then listed with an estimated c 32m of drop based on the 228m summit spot height appearing on this map and re-interpolation of bwlch contouring giving an estimated bwlch height of c 196m.
 |
| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
The name of the hill is Tŵr Glas and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), it is positioned overlooking the A 493 road which is to its north-west and has the small community of Arthog towards the south-west and the town of Dolgellau towards the east.
The summit and southern section of the hill is a part of designated open access land with a public footpath approaching the hill from the west probably being the most convenient ascent route, this follows the lower northern section of the hill before entering the open access land toward the east of the summit.
The confirmation of the reclassification of Tŵr Glas to 200m Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Tŵr Glas
Summit Height: 227.4m
Summit Grid Reference: SH 67218 16437
Bwlch Height: 193.6m
Bwlch Grid Reference: SH 67439 16279
Drop: 33.8m
 |
| LIDAR image of Tŵr Glas |
Therefore, the 227.4m LIDAR analysis for the summit position at SH 67218 16437 and the 193.6m LIDAR analysis for the bwlch position at SH 67439 16279 gives this hill 33.8m of drop, which confirms its reclassification to 200m Twmpau status.
The full details for the hill are:
Group: Cadair Idris
Name: Tŵr Glas
OS 1:50,000 map: 124
Summit Height: 227.4m (LIDAR)
Summit Grid Reference: SH 67218 16437 (LIDAR)
Bwlch Height: 193.6m (LIDAR)
Bwlch Grid Reference: SH 67439 16279 (LIDAR)
Drop: 33.8m (LIDAR)
Myrddyn Phillips (June 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Gribin (SH 675 168) – 200m Sub-Twmpau reclassified to 200m Twmpau (17th reclassification)
There has been confirmation of a reclassification to the 200m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:
200m Twmpau - Welsh hills at and 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 and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
This hill was listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website as it was thought not to meet the criteria then used for the main P30 list; however this list has now been standardised and interpolated heights and drop values also included, resulting in this hill being listed with an estimated c 39m of drop, based on an estimated c 211m summit height and an estimated bwlch height of c 172m based on bwlch map contouring between 170m – 180m. The details for this hill were later amended when the Ordnance Survey Interactive Coverage Map hosted on the Geograph website became available online and it was then listed with a 211m summit height based on the spot height appearing on this map.
 |
| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
The name of the hill is Gribin and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), it is positioned overlooking the A 493 road which is to its north and has the small community of Arthog towards the south-west and the town of Dolgellau towards the east.
The summit and upper southern section of the hill is a part of designated open access land and a public footpath leads toward this from the west south-west of the hill, with another option for an ascent following a public footpath from the north-east of the hill.
The confirmation of the reclassification of Gribin to 200m Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Gribin
Summit Height: 209.3m
Summit Grid Reference: SH 67559 16814
Bwlch Height: 169.7m
Bwlch Grid Reference: SH 67588 16670
Drop: 39.6m
 |
| LIDAR image of Gribin |
Therefore, the 209.3m LIDAR analysis for the summit position at SH 67559 16814 and the 169.7m LIDAR analysis for the bwlch position at SH 67588 16670 gives this hill 39.6m of drop, which confirms its reclassification to 200m Twmpau status.
The full details for the hill are:
Group: Cadair Idris
Name: Gribin
OS 1:50,000 map: 124
Summit Height: 209.3m (LIDAR)
Summit Grid Reference: SH 67559 16814 (LIDAR)
Bwlch Height: 169.7m (LIDAR)
Bwlch Grid Reference: SH 67588 16670 (LIDAR)
Drop: 39.6m (LIDAR)
Myrddyn Phillips (May 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Pt. 296.1m (SH 694 169) – 200m Sub-Twmpau addition (16th reclassification)
There has been confirmation of an addition to the 200m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:
200m Twmpau - Welsh hills at and 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 and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
This hill was not listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website as it did not meet the criteria then used for this category of hill; however this list has now been standardised and interpolated heights and drop values also included, resulting in this hill being listed with 26m of drop, based on the 297m summit spot height and the 271m bwlch spot height that appear on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.
 |
| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
As the name of the ffridd taking in this hill’s summit has not been confirmed the hill is being listed by the point (Pt. 296.1m) notation and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and the hill is positioned with the A 493 road to its north and has the town of Dolgellau towards its east.
As the hill is a part of designated open access land an ascent from a variety of directions is feasible, with a minor road towards its east and a public footpath towards its north and a bridleway towards its south probably giving the easiest option for ascent.
The confirmation of the addition of this hill to 200m Sub-Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Pt. 296.1m
Summit Height: 296.1m
Summit Grid Reference: SH 69444 16921
Bwlch Height: 271.0m
Bwlch Grid Reference: SH 69406 17012
Drop: 25.0m
 |
| LIDAR image of Pt. 296.1m |
Therefore, the 296.1m LIDAR analysis for the summit position at SH 69444 16921 and the 271.0m LIDAR analysis for the bwlch position at SH 69406 17012 gives this hill 25.0m of drop, which confirms its addition to 200m Sub-Twmpau status.
The full details for the hill are:
Group: Cadair Idris
Name: Pt. 296.1m
OS 1:50,000 map: 124
Summit Height: 296.1m (LIDAR)
Summit Grid Reference: SH 69444 16921 (LIDAR)
Bwlch Height: 271.0m (LIDAR)
Bwlch Grid Reference: SH 69406 17012 (LIDAR)
Drop: 25.0m (LIDAR)
Myrddyn Phillips (May 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Pt. 296.6m (SH 693 171) – 200m Sub-Twmpau addition (15th reclassification)
There has been confirmation of an addition to the 200m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:
200m Twmpau - Welsh hills at and 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 and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
This hill was not listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website as it did not meet the criteria then used for this category of hill; however this list has now been standardised and interpolated heights and drop values also included, resulting in this hill being listed with 25m of drop, based on the 297m summit spot height and the 272m bwlch spot height that appear on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.
 |
| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
As the name of the ffridd taking in this hill’s summit has not been confirmed the hill is being listed by the point (Pt. 296.6m) notation and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and the hill is positioned with the A 493 road to its north and has the town of Dolgellau towards its east.
As the hill is a part of designated open access land an ascent from most directions is feasible, with a minor road towards its east and a public footpath towards its north and a bridleway towards its south probably giving the easiest option for ascent.
The confirmation of the addition of this hill to 200m Sub-Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Pt. 296.6m
Summit Height: 296.6m
Summit Grid Reference: SH 69333 17107
Bwlch Height: 272.2m
Bwlch Grid Reference: SH 69427 17196
Drop: 24.4m
 |
| LIDAR image of Pt. 296.6m |
Therefore, the 296.6m LIDAR analysis for the summit position at SH 69333 17107 and the 272.2m LIDAR analysis for the bwlch position at SH 69427 17196 gives this hill 24.4m of drop, which confirms its addition to 200m Sub-Twmpau status.
The full details for the hill are:
Group: Cadair Idris
Name: Pt. 296.6m
OS 1:50,000 map: 124
Summit Height: 296.6m (LIDAR)
Summit Grid Reference: SH 69333 17107 (LIDAR)
Bwlch Height: 272.2m (LIDAR)
Bwlch Grid Reference: SH 69427 17196 (LIDAR)
Drop: 24.4m (LIDAR)
Myrddyn Phillips (May 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Craig y Castell (SH 694 173) – 200m Sub-Twmpau reclassified to 200m Twmpau (14th reclassification)
There has been confirmation of a reclassification to the 200m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:
200m Twmpau - Welsh hills at and 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 and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
This hill was listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website as it did not meet the criteria then used for the main P30 list; however this list has now been standardised and interpolated heights and drop values also included, resulting in this hill being listed with an estimated c 33m of drop, based on the 297m summit spot height that appears on Harvey maps and an estimated bwlch height of c 264m based on bwlch contouring between 260m – 270m. The details for this hill were later amended when the Ordnance Survey Interactive Coverage Map hosted on the Geograph website became available online and it was then listed with 34m of drop based on the 298m summit and 264m bwlch spot heights that appear on this map.
 |
| Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website |
The name of the hill is Craig y Castell and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and the hill is positioned overlooking the A 493 road to its north-west and has the town of Dolgellau towards its east.
As the upper section of the hill is a part of designated open access land an ascent from most directions is feasible, with a minor road towards its south-east and a public footpath towards its north probably giving the easiest option for ascent.
The confirmation of the reclassification of Craig y Castell to 200m Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Craig y Castell
Summit Height: 297.1m
Summit Grid Reference: SH 69405 17302
Bwlch Height: 263.5m
Bwlch Grid Reference: SH 69186 17218
Drop: 33.6m
 |
| LIDAR image of Craig y Castell |
Therefore, the 297.1m LIDAR analysis for the summit position at SH 69405 17302 and the 263.5m LIDAR analysis for the bwlch position at SH 69186 17218 gives this hill 33.6m of drop, which confirms its reclassification to 200m Twmpau status.
The full details for the hill are:
Group: Cadair Idris
Name: Craig y Castell
OS 1:50,000 map: 124
Summit Height: 297.1m (LIDAR)
Summit Grid Reference: SH 69405 17302 (LIDAR)
Bwlch Height: 263.5m (LIDAR)
Bwlch Grid Reference: SH 69186 17218 (LIDAR)
Drop: 33.6m (LIDAR)
Myrddyn Phillips (May 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Craig y Merwydd (SH 644 134) – 200m Sub-Twmpau reclassified to 200m Twmpau (13th reclassification)
There has been confirmation of a reclassification to the 200m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips and subsequently confirmed via a survey with the Trimble GeoXH 6000, with the criteria for this list being:
200m Twmpau - Welsh hills at and 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 and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
This hill was listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website as it did not meet the criteria then used for the main P30 list; however this list has now been standardised and interpolated heights and drop values also included, resulting in this hill being listed with an estimated c 32m of drop, based on the 296m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 264m based on bwlch contouring between 260m – 270m. This drop value was later amended to c 33m based on the larger scaled contours on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.
The name of the hill is Craig y Merwydd (composition given as Craigymerwydd on contemporary maps) and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and the hill is positioned overlooking the A 493 road to its north-west and has the small community of Arthog to the north.
 |
| Craig y Merwydd (SH 644 134) |
 |
| Extract from the Ordnance Survey series of Six-Inch maps |
As the upper section of the hill is a part of designated open access land an ascent from most directions is feasible, with a minor road to its immediate south giving the easiest option.
The confirmation of the reclassification of Craig y Merwydd to 200m Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The 1m DTM LIDAR analysis gives the hill the following details:
Name: Craig y Merwydd
Summit Height: 295.5m
Summit Grid Reference: SH 64413 13459
Bwlch Height: 261.0m
Bwlch Grid Reference: SH 64606 13315
Drop: 34.5m
 |
| LIDAR image of Craig y Merwydd |
Therefore, the 295.5m LIDAR analysis for the summit position at SH 64413 13459 and the 261.0m LIDAR analysis for the bwlch position at SH 64606 13315 gives this hill 34.5m of drop, with the details from the Trimble GeoXH 6000 survey being 295.7m (converted to OSGM15) summit at SH 64413 13459 and 261.2m (converted to OSGM15) bwlch at SH 64605 13317, giving this hill 34.6m of drop, which confirms its reclassification to 200m Twmpau status.
The full details for the hill are:
Group: Cadair Idris
Name: Craig y Merwydd
OS 1:50,000 map: 124
Summit Height: 295.7m (converted to OSGM15)
Summit Grid Reference: SH 64413 13459
Bwlch Height: 261.2m (converted to OSGM15)
Bwlch Grid Reference: SH 64605 13317
Drop: 34.6m (converted to OSGM15)
For details on the survey of Craig y Merwydd
 |
| The Trimble GeoXH 6000 gathering data at the summit of Craig y Merwydd |
For details on the survey of Craig y Merwydd
Myrddyn Phillips (May 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Gwastad Meirionydd (SH 589 071) – 200m Sub-Twmpau addition (12th reclassification)
There has been an addition to the 200m Twmpau due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:
200m Twmpau - Welsh hills at and 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 and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
Prior to LIDAR analysis this hill was listed with 19m of drop based on the 214m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and the bwlch spot height of 195m that appears on the Ordnance Survey 1:25,000 Explorer map.
 |
| Extract from the Ordnance Survey 1:25,000 Explorer map |
The name of the hill is Gwastad Meirionydd and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and the hill is positioned between the coast to its north-west and the Afon Dysynni to its south-east and has the small communities of Llwyngwril to the north and Llanegryn to the south-east.
If wanting to visit the hill permission to do so should be sought as it is not a part of designated open access land, however the track to its west and north is a bridleway and is not too far from the high point of the hill.
The addition of Gwastad Meirionydd to 200m Sub-Twmpau status is due to LIDAR analysis of the bwlch conducted by Myrddyn Phillips, with the summit of the hill not covered by LIDAR. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
The 2m DTM LIDAR analysis gives the hill the following details:
Gwastad Meirionydd
Summit Height: 214m
Summit Grid Reference: SH 589 071
Bwlch Height: 191.5m
Bwlch Grid Reference: SH 59229 08003
Drop: 23m
 |
| LIDAR image of Gwastad Meirionydd |
Therefore, the 191.5m LIDAR analysis for the bwlch position at SH 59229 08003 when coupled with the 214m summit height gives this hill 23m of drop, which is sufficient for 200m Sub-Twmpau status.
The full details for the hill are:
Group: Cadair Idris
Name: Gwastad Meirionydd
Summit Height: 214m
Summit Grid Reference: SH 589 071
Bwlch Height: 191.5m (LIDAR)
Bwlch Grid Reference: SH 59229 08003 (LIDAR)
OS 1:50,000 map: 124
Drop: 23m
Myrddyn Phillips (May 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Ffridd Tyddyn Mawr (SH 654 140) – 200m Sub-Twmpau addition (11th reclassification)
Survey post for Ffridd Tyddyn Mawr
Significant Name Changes post for Ffridd Tyddyn Mawr
There has been a confirmation of an addition to the 200m Twmpau with the summit height, drop and status of the hill confirmed by a survey with the Trimble GeoXH 6000, which was conducted by Myrddyn Phillips and took place on the 17th February 2018, and LIDAR analysis for the bwlch.
The criteria for this listing are:
200m Twmpau - Welsh hills at and 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 and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
The hill did not appear in the original Welsh P30 lists on Geoff Crowder’s v-g.me website as it did not meet the criteria then adopted for the Hills to be surveyed sub list. The hill was subsequently listed in the sub category after this was standardised and interpolated drop values added, and was included when the updates to the 200m Welsh P30s were published for the Cadair Idris group of hills on Mapping Mountains on the 7th July 2014.
Prior to the survey with the Trimble GeoXH 6000 the hill was listed with 20m of drop, based on the 274m summit spot height and 254m bwlch spot height that appear on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.
The bounded land where the summit of this hill is situated is named Ffridd Tyddyn Mawr and it is adjoined to the Cadair Idris group of hills, which is situated in the south-western part of North Wales (Region A, Sub-Region A3), and is positioned above the double lakes of Llynnau Cregennan which are to its north north-east and the small community of Arthog which is to its west north-west.
As the upper section of the hill is a part of designated open access land permission to visit does not need to be sought, for those wishing to visit the hill it can be approached from the lakeside car park adjacent to Llynnau Cregennan where a series of gates give access from one walled and bounded ffridd to the next.
The confirmation that Ffridd Tyddyn Mawr is a 200m Sub-Tumpau was due to the survey with the Trimble GeoXH 6000 and LIDAR analysis, resulting in a 273.2m (converted to OSGM15) summit height and a 251.2m (LIDAR) bwlch height, with these values giving the hill 22.0m of drop which is sufficient for its classification to this sub list.
The full details for the hill are:
Group: Cadair Idris
Summit Height: 273.2m (converted to OSGM15)
Name: Ffridd Tyddyn Mawr
OS 1:50,000 map: 124
Summit Grid Reference: SH 65486 14081
Drop: 22.0m (Trimble summit and LIDAR bwlch)
 |
| Ffridd Tyddyn Mawr (SO 654 140) now confirmed as a 200m Sub-Twmpau addition |
Myrddyn Phillips (March 2018)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Erw Penlan (SO 045 495) – 200m Sub-Twmpau addition (10th reclassification)
Survey post for Erw Penlan
Significant Name Changes post for Erw Penlan
There has been a confirmation of an addition to the 200m Twmpau (thirty welsh metre prominences and upward) ranks of hills due to a survey with the Trimble GeoXH 6000, with the survey that confirmed this addition being conducted on the 13th June 2017.
The criteria for 200m Twmpau status is all 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, and it is the inclusion of this hill in the 200m Sub-Twmpau that has been confirmed.
The hill did not appear in the original Welsh P30 lists on Geoff Crowder’s v-g.me website as it did not meet the criteria then adopted for the Hills to be surveyed sub list. The hill was later classified and listed in the sub category after this was standardised and interpolated drop values added, and was included when the updates to the 200m Welsh P30s were published for the Mynydd Epynt group of hills on Mapping Mountains on the 25th August 2014. The listing this hill is now a part of is named Twmpau (thirty welsh metre prominences and upward) and its height, drop and status was confirmed by a survey with the Trimble GeoXH 6000.
Prior to the survey with the Trimble GeoXH 6000 the hill was listed by the name of Coetgae Fawr with an estimated c 21m of drop, based on the 213m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 192m based on interpolation of bwlch contouring between 190m – 200m.
The name that this hill is being listed by is Erw Penlan (see Significant Name Changes) and it is adjoined to the Mynydd Epynt range, which is situated in the south-eastern part of Mid and West Wales (Region B, Sub-Region B2) with its Cardinal Hill being Clepyn Melyn (SN 961 464), and it is positioned above the A 483 road which is to the hill’s north and east, with the town of Llanfair-ym-Muallt (Builth Wells) positioned to its north.
As the hill does not form a part of designated open access land permission to visit should be sought, for those wishing to do so a public footpath connects between minor country lanes to the north and south of the hill’s summit and proceeds around the upper western part of the hill.
The full details for the hill are:
Cardinal Hill: Clepyn Melyn
Summit Height: 212.1m (converted to OSGM15)
Name: Erw Penlan
OS 1:50,000 map: 147
Summit Grid Reference: SO 04597 49535
Drop: 20.9m (converted to OSGM15)
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| Erw Penlan (SO 045 495) now confirmed as a 200m Sub-Twmpau addition |
Myrddyn Phillips (August 2017)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Y Pincin (SH 723 581) – 200m Twmpau addition (9th reclassification)
Survey post for Y Pincin
There has been a confirmation of an addition to the 200m Twmpau (thirty welsh metre prominences and upward) ranks of hills due to a survey with the Trimble GeoXH 6000, with these details being retrospective as the survey that confirmed this addition was conducted on the 24th December 2013.
The criteria for 200m Twmpau status is all 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.
This hill did not appear in the original Welsh P30 lists when published on Geoff Crowder’s v-g.me website even though the hill is given a 264m summit spot height on the Ordnance Survey 1:25,000 Explorer map and has bwlch contouring between 220m – 230m. Its addition to the P30 ranks was announced shortly before the hill was surveyed with the Trimble GeoXH 6000, and prior to this survey the hill was listed with c 36m of drop.
The name of the hill is Y Pincin and it is situated in the Carneddau range with its Cardinal Hill being Creigiau Gleision (SH 729 615) and is positioned immediately above the A5 road which is to its south and the small community of Capel Curig.
The upper section of the hill is a part of designated open access land, with a public footpath leaving Capel Curig to the west of the hill and heading toward the summit. Although this hill makes an enjoyable walk and scramble in its own right, a more fulfilling experience can be had when combining it with its higher neighbours toward the north.
The full details for the hill are:
Cardinal Hill: Creigiau Gleision
Summit Height: 263.5m (converted to OSGM15)
Name: Y Pincin
OS 1:50,000 map: 115
Summit Grid Reference: SH 72357 58126
Drop: 34.7m (converted to OSGM15)
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| Y Pincin (SH 723 581) has now been confirmed as a 200m Twmpau by a survey with the Trimble GeoXH 6000 |
Myrddyn Phillips (August 2017)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Dinas Mawr (SH 808 539) – 200m Sub-Twmpau reclassified to 200m Twmpau (8th reclassification)
Survey post for Dinas Mawr
There has been a confirmation of a reclassification to the 200m Twmpau (thirty welsh metre prominences and upward) ranks of hills due to a survey with the Trimble GeoXH 6000, with these details being retrospective as the survey that confirmed this reclassification was conducted on the 24th December 2013.
The criteria for 200m Twmpau status is all 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.
This hill was listed in the Hills to be surveyed sub list accompanying the original Welsh P30 lists on Geoff Crowder’s v-g.me website and was only reclassified to P30 status when the sub list was standardised and interpolated drop values were accepted for qualification to the main P30 list.
Prior to the survey with the Trimble GeoXH 6000 the hill was listed with 33m of drop based on the 254m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 221m bwlch spot height that appears on the Ordnance Survey enlarged mapping hosted on the Geograph website.
The name of the hill is Dinas Mawr and it is situated in the Mynydd Hiraethog range with its Cardinal Hill being Mwdwl Eithin (SH 917 540) and is positioned immediately above the A5 road which is to its south, and is placed between the small communities of Capel Garmon to the north north-east and Penmachno to the south south-west.
The upper section of the hill is a part of designated open access land and this can be accessed from public footpaths originating from the A5 road south-west of the summit or from a minor lane to the east of the summit.
The full details for the hill are:
Cardinal Hill: Mwdwl Eithin
Summit Height: 254.0m (converted to OSGM15)
Name: Dinas Mawr
OS 1:50,000 map: 116
Summit Grid Reference: SH 80884 53931
Drop: 33.9m (converted to OSGM15)
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| Dinas Mawr (SH 808 539) this hill's reclassification to 200m Twmpau status is now confirmed by a survey with the Trimble GeoXH 6000 |
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Pen y Gaer (SO 139 976) – 200m Twmpau reclassified to Trichant (7th reclassification)
Survey post for Pen y Gaer
There has been a reclassification of a 200m Twmpau (thirty welsh metre prominences and upward) to the listing of Y Trichant due to surveying with the Trimble GeoXH 6000.
The details relating to this hill’s inclusion in the listing of Y Trichant are retrospective as the survey with the Trimble took place on the 11th January 2015 and the Hill Reclassifications post for its 300m Twmpau status was published on Mapping Mountains on the 12th January 2015.
The criteria for 200m Twmpau status is all Welsh hills at or above 200m and below 300m in height with 30m minimum drop, whilst Y Trichant is the title for the hills in the 300m height band of the Twmpau and takes in all Welsh hills at or above 300m and below 400m in height with 30m minimum drop, with the introduction to the re-naming of this list appearing on Mapping Mountains on the 13th May 2017.
Prior to the survey with the Trimble GeoXH 6000 the hill was listed with 87m of drop based on the 299m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and the 212m bwlch spot height that appears on the Ordnance Survey enlarged mapping hosted on the Geograph website.
The hill is situated in the Carnedd Wen range with its Cardinal Hill being Stingwern Hill (SJ 132 014) and is placed in the North Wales Region (Region A, Sub-Region A4), and is positioned with the small community of Bettws Cedewain to the west south-west and Aber-miwl (Abermule) to the south-east.
As the summit of the hill is not a part of designated open access land permission to visit its high point should be sought. For those seeking this and wishing to visit there is a public footpath just to the north of the summit which can be accessed from either the north-east or the south-west.
The name of the hill is Pen y Gaer and it is only the third hill that I know of whose status has been altered due to the Ordnance Survey remodelling known as OSGM15. This remodelling has increased the accurately known height of hills in Wales by approximately 2-4cm, and the other two hills whose status was altered because of OSGM15 are Calf Top (SD 664 856) and Carn Ysgubor (SM 699 246).
Surveyed height of Pen y Gaer pre OSGM15 = 299.974m
Surveyed height of Pen y Gaer post OSGM15 = 300.002m
The full details for the hill are:
Cardinal Hill: Stingwern Hill
Summit Height: 300.0m (converted to OSGM15)
Name: Pen y Gaer
OS 1:50,000 map: 136
Summit Grid Reference: SO 13997 97677
Bwlch Height: 214.8m (converted to OSGM15)
Bwlch Grid Reference: SO 13170 99222
Drop: 85.2m
Bwlch Grid Reference: SO 13170 99222
Drop: 85.2m
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| Pen y Gaer (SO 139 976) reclassified from a 200m Twmpau to a Trichant |
Myrddyn Phillips (June 2017)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Moelfryn (SH 568 511) – 200m Twmpau reclassified to 200m Sub-Twmpau (6th reclassification)
Significant Height Revisions post for Moelfryn
There has been a reclassification to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis initially conducted by Aled Williams and subsequently by Myrddyn Phillips.
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| LIDAR image of Moelfryn (SH 568 511) |
The criteria for the list that this reclassification 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. The list is authored by Myrddyn Phillips, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
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| 200m Twmpau by Myrddyn Phillips |
The name the hill is now listed by is Moelfryn, and it is adjoined to the Moel Hebog group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with a the B4418 road to its north-west and the A4085 road to its east, and the A488 road to its south-east, and has the village of Beddgelert towards the south south-east.
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 accompanying Hills to be surveyed sub list, with a summit height of 277m, based on the spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.
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| Extract from the Ordnance Survey 1:50,000 Landranger map |
After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 30m of drop, based on the 277m summit spot height and an estimated c 247m bwlch height, based on interpolation of 10m contouring between 240m - 250m.
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| 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 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 Ordnance Survey series of Six-Inch maps formed the base map Ordnance Survey used for many decades leading to the production of the 1:10,000 Series of maps, both have now been superseded by the digitised Master Map. The Six-Inch maps suggest the contemporary 277m spot height may be erroneous as this summit is immersed in conifer plantation and the only spot height preceding it that has appeared on Ordnance Survey maps is the imperial height of 901ft (274.6m) which originated on the Six-Inch series. Therefore, there seems no evidence to support how a spot height has changed by 2.4m when the summit is immersed in trees.
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| Extract from the Ordnance Survey series of Six-Inch maps |
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 reclassification of this hill from 200m Twmpau status is due to LIDAR analysis, resulting in a 274.7m summit height and a 246.1m bwlch height, with these values giving this hill 28.6m of drop, which is sufficient for it to be classified as a 200m Sub-Twmpau.
The full details for the hill are:
Group: Moel Hebog
Name: Moelfryn
OS 1:50,000 map: 115
Summit Height: 274.7m (LIDAR)
Summit Grid Reference: SH 56888 51162 (LIDAR)
Bwlch Height: 246.1m (LIDAR)
Bwlch Grid Reference: SH 56415 51302 (LIDAR)
Drop: 28.6m (LIDAR)
My thanks to Aled Williams for sending the details of this hill to me
Myrddyn Phillips (May 2017)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Mynydd y Drum (SN 807 097) - 200m Twmpau reclassified to 200m Sub-Twmpau (5th reclassification)
Survey post for Mynydd y Drum
Survey post for Mynydd y Drum
There has been a reclassification to the listing of Twmpau (thirty welsh metre prominences and upward) hills due to analysis of LIDAR data by Kevin McGovern and also independently by Aled Williams, and subsequently confirmed via a survey with the Trimble GeoXH 6000. The hill has been reclassified from a 200m Twmpau to a 200m Sub-Twmpau, with the criteria for the former being all hills in Wales at or above 200m and below 300m in height that have a minimum drop of 30m, and the criteria for the sub category being all hills in Wales at or above 200m and below 300m in height with 20m or more and below 30m of drop.
The hill had been listed with an estimated drop of c 53m based on an estimated bwlch height of c 244m and the 297m summit height positioned at SN 807 098 derived from the spot height that appears on the Ordnance Survey 1:25,000 Explorer map numbers 12 and 165, whilst the Ordnance Survey 1:50,000 Landranger map number 160 gives a 298m summit spot height at the same position. This latter spot height is derived from the 978.1ft (298.1ft) height on the Ordnance Survey old Six-Inch map.
When this hill was originally listed in the Welsh P30 lists on the v-g.me website it had an accompanying note which stated ‘3 points of 300m on 1985 map may probably no longer exist (quarrying)’. The hand written Master List stated ‘Due to opencast workings the three points of 300c at GR 830 112 on 1985 1:50,000 map probably no longer exist’. These three points are in the vicinity of where a 984ft (299.9m) height appears on the Ordnance Survey old Six Inch map and in all likelihood signified where the summit of this hill was once positioned. Since this time the opencast workings which take in the northern and eastern part of the larger hill known as Mynydd y Drum have destroyed the old 984ft (299.9m) summit, but in its place are two separate hills comprising the spoil from the mine workings, with this Hill Reclassifications post concentrating on the remaining ‘natural’ and now lower of these three summits.
Prior to analysis of LIDAR data Mynydd y Drum was listed with one summit, but due to opencast mining a further two summits have been created which are artificial and comprise the remains of waste spoil, the hill which this Hill Reclassifications post details is the remaining ‘natural’ summit, which is now lower in height compared to the two artificial summits, this has resulted in new bylchau heights and positions and also drop values for these three hills, all of these will be detailed in this and the two previous Hill Reclassifications posts, with the other two hills being Teisen Priodas (SN 820 108) and MRF Tip (SN 828 114).
The hill is adjoined to the Fforest Fawr group with its Cardinal Hill being Fan Gyhirych (SN 880 191) and is placed in the Region of South Wales (Region C, Sub-Region C2), and is positioned between the small town of Ystradgynlais to the north-west and the village of Blaendulais (Seven Sisters) to the south-east.
The upper part of the hill is situated within open access land and can be easily accessed from a number of public footpaths that emanate from Cwm Tawe (Swansea Valley) to the north-west and from Cwm Dulais (Dulais valley) from the south-east.
The name of the hill is Mynydd y Drum and its reclassification to a 200m Sub-Twmpau is due to the analysis of LIDAR data by Kevin McGovern and also independently by Aled Williams. LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.
Kevin’s analysis of LIDAR data gives the hill the following details:
Mynydd y Drum
Summit Height: 296.1m (converted to OSGM15)
Summit Grid Reference: SN 80720 09754
Bwlch Height: 271.8m (converted to OSGM15)
Bwlch Grid Reference: SN 81526 10520
Drop: 24.3m
Therefore, the 296.1m LIDAR data produced for the summit position at SN 80720 09754 and the 271.8m LIDAR data produced for the bwlch position at SN 81526 10520 is sufficient for this hill to be reclassified from a 200m Twmpau to a 200m Sub-Twmpau with 24.3m of drop, with the details from the Trimble GeoXH 6000 survey being 296.2m (converted to OSGM15) summit at SN 80718 09753 and 271.4m bwlch (converted to OSGM15) at SN 81526 10519), giving this hill 24.8m of drop.
This now revises the total in the 200m Twmpau and the list will be updated accordingly.
The full details for the hill are:
Cardinal Hill: Fan Gyhirych
Summit Height: 296.2m (converted to OSGM15, Trimble data)
Name: Mynydd y Drum
OS 1:50,000 map: 160
Summit Grid Reference: SN 80718 09753
Drop: 24.8m (converted to OSGM15, Trimble data)
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| Mynydd y Drum (SN 807 097) now reclassified to a 200m Sub-Twmpau |
My thanks to Mark Jackson for bringing the details of this hill to my attention, and to Kevin McGovern and Aled Williams for their analysis of LIDAR data.
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Y Ceiliog Mawr (SH 594 598) - 200m Twmpau addition (4th reclassification)
There has been an addition of a hill to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis initially conducted by Aled Williams and subsequently by Myrddyn Phillips.
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| Y Ceiliog Mawr (SH 594 598). Photo: Aled Williams |
The hill was first proposed as a prospective P30 approximately two years ago by Aled Williams and it then waited to be Trimbled, but as it looked a daunting prospect the Trimble surveyor shied away from his duties. In the interim LIDAR became available.
The criteria for the list that this addition 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.
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| 200m Twmpau by Myrddyn Phillips |
The name the hill is listed by is Y Ceiliog Mawr, and it is adjoined to the Glyder Fawr group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with Llyn Peris and the A4086 road to its south-west, and has the town of Llanbertis 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 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 know whether any hill of note existed.
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| 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.
%20-%20LIDAR%20hill%201.jpg) |
| LIDAR image of Y Ceiliog Mawr (SH 594 598) |
Therefore, the addition of this hill to 200m Twmpau status is due to LIDAR analysis, resulting in a 220.5m summit height and a 182.3m bwlch height, with these values giving this hill 38.2m of drop, which is sufficient for it to be classified as a 200m Twmpau.
The full details for the hill are:
Group: Glyder Fawr
Name: Y Ceiliog Fawr
OS 1:50,000 map: 115
Summit Height: 220.5m (LIDAR)
Summit Grid Reference: SH 59467 59848 (LIDAR)
Bwlch Height: 182.3m (LIDAR)
Bwlch Grid Reference: SH 59529 59826 (LIDAR)
Drop: 38.2m (LIDAR)
My thanks to Aled Williams for supplying the details of his LIDAR analysis of this hill.
Myrddyn Phillips (December 2016)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Gallt y Celyn (SH 811 542) - 200m Sub-Twmpau reclassified to 200m Twmpau (3rd reclassification)
Summit survey post for Gallt y Celyn
Bwlch survey post for Gallt y Celyn
Significant Name Changes post for Gallt y Celyn
There has been a reclassification within the 200m Twmpau (thirty welsh metre prominences and upward) hill list instigated by a survey with the Trimble GeoXH 6000. The hill has a convoluted history of reclassification and is situated just to the north of the A 5 and southward of the small community of Capel Garmon and south-eastward of the town of Betws-y-coed, and is positioned in the Mynydd Hiraethog range of hills.
The Trimble GeoXH 6000 survey that resulted in this hill’s reclassification from a 200m Sub-Twmpau to a 200m Twmpau was conducted in the afternoon of the 23th February 2016 on a beautiful winter’s day in good, dry and sunny conditions.
The hill is unnamed on current Ordnance Survey maps but is given as a part of Gallt y Celyn on the Tithe map and therefore this name is deemed appropriate to use.
Access to the hill is relatively easy as there is a public footpath approaching from the north which can be accessed from Capel Garmon, and also one from the south-east which can be accessed from a steep minor lane that heads north from the A 5. The summit of the hill is only a short distance from where these footpaths meet and is on open access land.
The hill has a convoluted history of inclusion and exclusion from the 200m P30 Welsh list as it was originally included in the ‘Hills to Survey’ Sub-List that accompanied the main P30 lists on Geoff Crowder’s v-g.me website. This Sub-List was reliant upon the details on Ordnance Survey maps being correct and did not take in contour interpolation for inclusion within the main P30 list. After the Sub-List was standardised and contour interpolation used, the hill was reclassified to a P30 with c 30m of drop, based on a 258m summit spot height and an estimated bwlch height of c 238m. To complicate matters this hill had twin tops, both given a 258m spot height on Ordnance Survey maps, these tops were surveyed with the Trimble on the 24th December 2013 with the following results:
257.610m (converted to OSGM15) at SH 81121 54259.
257.093m (converted to OSGM15) at SH 81007 54476.
Although the twin tops had been separated the bwlch was not surveyed and as it was estimated to be c 238m high, the drop for this hill was accepted as being just under the qualifying minimum drop of 30m and therefore the hill re-joined the ranks of Subs.
It was always my intention to survey the bwlch and determine once and for all the classification of the hill, and on the 23rd February I found myself immersed in a water laden bog gathering the allotted five minutes of data. This survey resulted in a bwlch height of 227.5m (227.529m, converted to OSGM15), which gave this hill 30.1m (30.081m) of drop, and therefore it re-joins the ranks of P30 Twmpau hills.
The full details for the hill are:
Cardinal Hill: Mwdwl Eithin
Summit Height: 257.6m (converted to OSGM15)
Name: Gallt y Celyn
OS 1:50,000 map: 116
Summit Grid Reference: SH 811 542
Drop: 30.1m (converted to OSGM15)
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| Gallt y Celyn (SH 811 542) in the centre foreground of this photograph and which has now been re-instated as a 200m P30 Twmpau. Photograph taken from the summit of Dinas Mawr (SH 808 539) |
For details on the survey that resulted in this hill being reclassified from a 200m Sub-Twmpau to a 200m Twmpau please click {here} for summit and {here} for the bwlch survey.
Myrddyn Phillips (February 2016)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Bwlch Clump (SJ 170 108) - 200m Twmpau reclassified to 200m Sub-Twmpau (2nd reclassification)
Survey post for Bwlch Clump
Summit Relocations post for Bwlch Clump
Significant Name Changes post for Bwlch Clump
There has been a reclassification within the 200m Twmpau (thirty welsh metre prominences and upward) hill list instigated by a survey with the Trimble GeoXH 6000. The hill has twin map heighted summits and is situated to the south-east of Dyffryn Meifod and to the north-west of the Maesmawr valley and forms part of the Carnedd Wen range of hills.
These details are retrospective, as the Trimble GeoXH 6000 survey that resulted in this hill’s reclassification from a P30 Twmpau hill to a 200m Sub- Twmpau hill was conducted in the afternoon of the 20th January 2016 on a beautiful crisp winter day in good, dry and sunny conditions.
The lower section of the hill can be accessed from public footpaths to its west and east. However, its summit does not appear on open access ground, therefore permission to visit the high point should be sought.
The hill was originally included in the main 200m P30 list that appeared on Geoff Crowder’s v-g.me website as a single summit under the current 1:25,000 Explorer map height of 262m (SJ 173 109), and listed under the partly invented name of Pen y Bryn Wood (Bryn Wood being the name of the wood to the north-east of the originally listed hill’s summit). The hill gained a twin summit when the Ordnance Survey enlarged map on the Geograph website included a 262m spot height for the adjacent hill at SJ 170 108, which was named as Bwlch Clump on this map. According to map contours the drop between each was not sufficient for both to be included as P30s, with interpolation suggesting c 19m of drop.
Therefore the purpose of this survey was to ascertain which of the two summits is higher and separate their twin top status, and see if the drop between each was sufficient for the lower Trimbled summit to be included as a Sub-Twmpau and ascertain if the higher summit retained its P30 status, as the listed drop value for this hill was c 30m, which was based on bwlch contour interpolation.
The survey results for this once twin topped P30 are:
Pt . 262.8m (originally listed as Pen y Bryn Wood)
262.8m (converted to OSGM15) summit at SJ 17354 10914
243.5m (converted to OSGM15) bwlch at SJ 17190 10797
19.4m drop
Bwlch Clump
263.9m (converted to OSGM15) summit at SJ 17063 10813
234.9m (converted to OSGM15) bwlch at SJ 17089 10581
29.1m drop
Therefore the survey with the Trimble GeoXH 6000 confirms that Bwlch Clump is 1.1m higher than Pt. 262.8m, and that Pt. 262.8m has 19.4m of drop and is not listed as a Sub-Twmpau, and that Bwlch Clump has 29.1m of drop and is therefore reclassified to a 200m Sub-Twmpau.
The full details for the new status of this hill are:
Cardinal Hill: Carnedd Wen
Summit Height: 263.9m (converted to OSGM15)
Name: Bwlch Clump
OS 1:50,000 map: 125
Summit Grid Reference: SJ 17063 10813
Drop: 29.1m (converted to OSGM15)
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| Pt. 262.8m - now reclassified from a twin topped P30 to a non Sub-Twmpau. How the mighty fall!!! |
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| Bwlch Clump - now reclassified from a twin topped P30 to a 200m Sub-Twmpau |
For details on the survey that resulted in this hill being reclassified from a 200m Twmpau to a 200m Sub-Twmpau please click {here}
Myrddyn Phillips (January 2016)
Mapping Mountains - Hill Reclassifications - 200m Twmpau
Broniarth (SJ 166 120) - 200m Sub-Twmpau addition (1st reclassification)
Survey post for Broniarth
There has been a confirmation of a new addition to the Sub category within the 200m Twmpau (thirty welsh metre prominences and upward) hill list instigated by a survey with the Trimble GeoXH 6000. The hill is situated between the small community of Meifod to its north-west and that of Maesmawr to its south-east and is part of the Carnedd Wen range of hills.
These details are retrospective, as the Trimble GeoXH 6000 survey that resulted in this hill’s confirmation as a 200m Sub- Twmpau was conducted on the 20th January 2016 on a beautiful crisp winter day in good, dry and sunny conditions.
The hill can be easily accessed from its south where a narrow lane crosses from south-west to north-east across its southerly flank. This would be a short visit of no more than a few minutes, so combining the hill with some of its neighbours is recommended. However, permission should be sought for those wishing to visit as the summit is not on open access land.
The hill is unnamed on current Ordnance Survey 1:25,000 Explorer maps but is part of land known locally as Broniarth and which appears on some Ordnance Survey maps as an extended name of either Broniarth or Broniarth Hill.
This is a confirmation of this hill’s addition to the 200m Sub-Twmpau ranks as current Ordnance Survey enlarged mapping on the Geograph website has a 247m spot height on this hill’s bwlch, with the summit having a 268m spot height on the Ordnance Survey 1:25,000 Explorer map and the enlarged map hosted on the Geograph website. These values give the hill 21m of drop, which compares favourably with the Trimble survey of 21.5m of drop.
The survey with the Trimble GeoXH 6000 resulted in a 267.9m (converted to OSGM15) summit height and a 246.5m (converted to OSGM15) bwlch height, giving this hill 21.5m of drop and confirming its entry in to the 200m Sub-Twmpau ranks.
The full details for the hill are:
Cardinal Hill: Carnedd Wen
Summit Height: 267.9m (converted to OSGM15)
Name: Broniarth
OS 1:50,000 map: 125
Summit Grid Reference: SJ 16648 12055
Drop: 21.5m (converted to OSGM15)
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| Broniarth (SJ 166 120) 200m Sub-Twmpau status now confirmed by the Trimble GeoXH 6000 |
For details on the survey that resulted in this hill being confirmed as a 200m Sub-Twmpau please click {here}
Myrddyn Phillips (January 2016)
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