Mapping Mountains – Hill Reclassifications – The Welsh Highlands – Uchafion Cymru

 

Graig Fach (SH 792 249) – Welsh Highland Sub reinstatement 

There has been a reinstatement to the listing of the The Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted by Aled Williams. 

Graig Fach (SH 792 249)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Graig Fach, and it is adjoined to the Arenig Fawr group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A2), and it is positioned with the A470 road to its west, a minor road to its south-east and the A494 road farther to its south-east, and has the town of Dolgellau towards the south-west. 

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

When the initial P10 sub list was completed in June 2020 this hill was listed with 10.2m of drop, based on a basic levelling survey conducted by Myrddyn Phillips on the 10.04.06, and listed with an estimated c 510m summit height and an estimate c 500m bwlch height, with an accompanying note stating that interpolation indicates an estimated c 501m bwlch height, which would mean this hill not being included as a Welsh Highland Sub.

The hill was subsequently analysed via LIDAR by Aled Williams, resulting in a 511.3m summit height and a 501.4m bwlch height, with these values giving this hill 9.9m of drop, which was insufficient for it to be classified as a Welsh Highland Sub.  However, with the drop value relatively close to the qualifying criterion of 10m this hill was prioritised for a survey with the Trimble GeoXH 6000. 

The Trimble GeoXH 6000 gathering data at the summit of Graig Fach.  Photo: Aled Williams

The Trimble GeoXH 6000 gathering data at the bwlch of Graig Fach.  Photo: Aled Williams

Therefore, the reinstatement of this hill to Welsh Highland Sub status is due to a Trimble GeoXH 6000 survey, resulting in a 511.0m summit height and a 501.0m bwlch height, with these values giving this hill 10.0m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Arenig Fawr

Name:  Graig Fach          

OS 1:50,000 map:  124

Summit Height:  511.0m (converted to OSGM15)

Summit Grid Reference:  SH 79262 24920

Bwlch Height:  501.0m (converted to OSGM15)

Bwlch Grid Reference:  SH 79278 24975    

Drop:  10.0m  

 

For the additions, deletions and reclassifications to the The Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (March 2025)

  

Mapping Mountains – Hill Reclassifications – The Welsh Highlands – Uchafion Cymru

Cefn Tyle Brych (SN 903 014) – Welsh Highland Sub deletion 

There has been a deletion to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Cefn Tyle Brych (SN 903 014)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Cefn Tyle Brych and it is adjoined to the Craig y Llyn group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with the A465 road to its north and the A4061 road to its east, and has the village of Treherbert towards the south-east.

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 11m of drop, based on a 539m summit height and an estimated c 528m bwlch height, based on interpolation of 5m contouring that appeared on online mapping. 

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

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

Therefore, the deletion of this hill from Welsh Highland Sub status is due to LIDAR analysis, resulting in a 538.5m summit height and a 528.7m bwlch height, with these values giving this hill 9.8m of drop, which is insufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Craig y Llyn

Name:  Cefn Tyle Brych

OS 1:50,000 map:  170

Summit Height:  538.5m (LIDAR)

Summit Grid Reference:  SN 90321 01411 (LIDAR)

Bwlch Height:  528.7m (LIDAR)

Bwlch Grid Reference:  SN 90482 01905 (LIDAR)   

Drop:  9.8m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (January 2024)

  

Mapping Mountains – Hill Reclassifications – The Welsh Highlands – Uchafion Cymru

Pt. 501.4m (SH 730 397) – Uchaf addition

There has been an addition to the listing of The Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams on the 19^th July 2020 and subsequent LIDAR analysis conducted by Aled Williams.

Pt. 501.4m (SH 730 397)

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

The Welsh Highlands – Uchafion Cymru – This is the revised draft title for the Welsh 500m P15s list that takes in all hills in Wales at or above 500m in height with 15m minimum drop.  The list is co-authored by Myrddyn Phillips and Aled Williams with the Introduction to the list being published on Mapping Mountains in November 2015 and an update relating to the list appearing on Mapping Mountains on the 19th June 2019.

The Welsh Highlands - Uchafion Cymru by Myrddyn Phillips and Aled Williams

The hill is being listed by the point (Pt. 501.4m) notation, and it is adjoined to the Arenig Fach group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A3), and it is positioned with the B4391 road to its north, the A470 road to its west and the A4212 road to its south, and has the village of Trawsfynydd towards the south-west.

This hill was not included in the original list of Welsh 500m P15s that later became known as Yr Uchafion and latterly as The Welsh Highlands – Uchafion Cymru, as with a small 500m ring contour and bwlch contouring between 480m – 490m that appear on the Ordnance Survey 1:25,000 Explorer map its interpolated drop value was judged insufficient for either Uchaf or 500m Sub-Uchaf status.

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

Since the original compilation of this list 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 mapping on the WalkLakes website and the Magic Maps website.

Extract from the WalkLakes website

One of the mapping resources now available online is the WalkLakes website which hosts an interactive Ordnance Survey map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available Ordnance Survey maps and for this hill a 504m spot height is given on the area of its summit.

Another resource available online is the interactive mapping originated from Ordnance Survey data hosted on the Magic Maps website.  This mapping also shows a 504m spot height on the summit area of this hill.

Extract from the Magic Maps website

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.  This resulted in its bwlch height being estimated as c 488m based on interpolation of 5m contouring between 485m – 490m.

Extract from the OS Maps website

The hill was first proposed as an Uchaf by Myrddyn Phillips and Aled Williams subsequently analysed the hill as follows:

Summit height of c 500m at SH 73026 39780 interpolated from OS paper maps.  Bwlch position estimated from QGIS modelling of OS Terrain 50 data to be c 487m at SH 72991 39724.  Enlarged-scale online OS maps give a summit height of 504m, which may be the result of a data modelling error caused by the forestry.

However, it was not until the survey with the Trimble GeoXH 6000 that the details for this hill could be accurately re-assessed.  The summit of this hill and a number of potential bwlch positions were subsequently surveyed, with the bwlch height and position given for this hill having been obtained from the data spread produced from the various bwlch surveys and scrutiny of aerial map comparisons.

At the summit of Pt. 501.4m

Gathering data during one of a number of surveys for the bwlch position of Pt. 501.4m

However, it was not until LIDAR became available that the details for this hill could be compared to the data produced from the Trimble GeoXH 6000 survey.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.  This resulted in the bwlch details produced by LIDAR analysis being prioritised.

Therefore, the confirmation of the addition of this hill to Uchaf status is due to a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis, resulting in a 501.4m summit height and a 485.7m bwlch height, with these values giving this hill 15.7m of drop, which is sufficient for it to be classified as an Uchaf.

The full details for the hill are:

Group:  Arenig Fach

Name:  Pt. 501.4m

OS 1:50,000 map:  124

Summit Height:  501.4m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 73011 39784 (Trimble GeoXH 6000)

Bwlch Height:  485.7m (LIDAR)

Bwlch Grid Reference:  SH 73070 39636 (LIDAR) 

  

Drop:  15.7m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

For the additions, deletions and reclassifications to the The Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

Myrddyn Phillips and Aled Williams (November 2020)

Mapping Mountains – Hill Reclassifications – The Welsh Highlands - Uchafion Cymru

Iwerddon (SH 686 479) – Welsh Highland P15 addition

There has been an addition to the listing of the The Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data, with confirmation from subsequent LIDAR analysis conducted by Aled Williams.

Iwerddon (SH 686 479)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Iwerddon and it is adjoined to the Moelwyn Mawr group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A2), and it is positioned with the A487 and the A496 roads to its south and the A470 road to its east, and has the town of Blaenau Ffestiniog towards the south-east.

This hill was not included in the original list of Welsh 500m P15s that later became known as Yr Uchafion and latterly as The Welsh Highlands – Uchafion Cymru, as with a 570m uppermost ring contour and no summit spot height and bwlch contouring between 560m – 570m that appear on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, it was difficult through interpolation to give this hill an estimated drop value.

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

Since the original compilation of this list there are now a number of interactive maps originated from Ordnance Survey data that are available online.  One of these is the mapping on the Magic Maps website, and this map gives this hill a summit spot height of 579m which is positioned at SH 68671 47997.

Extract from the Magic Maps website

Another resource now available online is the WalkLakes website which hosts an interactive map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available Ordnance Survey maps and for this hill it also shows the 579m summit spot height.

Extract from the WalkLakes map

The details for this hill were re-examined when the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on any other publicly available Ordnance Survey map and its non-contour map also gives a 579m summit spot height.

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

The details for this hill were also re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This mapping has an uppermost 575m ring contour and bwlch contouring between 560m – 565m, with interpolation giving an estimated c 564m bwlch height.

Extract from the OS 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. 

Therefore, the confirmation of the addition of this hill to Uchaf status is due to LIDAR analysis, resulting in a 578.7m summit height and a 561.8m bwlch height, with these values giving this hill 16.9m of drop, which is sufficient for it to be classified as an Uchaf.

The full details for the hill are:

Group:  Moelwyn Mawr

Name:  Iwerddon

OS 1:50,000 map:  115

Summit Height:  578.7m (LIDAR)

Summit Grid Reference:  SH 68673 47996 (LIDAR)

Bwlch Height:  561.8m (LIDAR)

Bwlch Grid Reference:  SH 68726 48082 (LIDAR) 

  

Drop:  16.9m (LIDAR)

 

For the additions, deletions and reclassifications to The Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 Welsh Highland P15s

Welsh Highland Subs

Myrddyn Phillips and Aled Williams (July 2020)

Mapping Mountains – Hill Reclassifications – The Welsh Highlands – Uchafion Cymru

Moel Darren (SH 952 413) – Uchaf reclassified to 500m Sub-Uchaf

There has been a reclassification to the listing of The Welsh Highlands – Uchafion Cymru due to a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams on the 19^th January 2020.

Moel Darren (SH 952 413)

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

The Welsh Highlands – Uchafion Cymru – This is the revised draft title for the Welsh 500m P15s list that takes in all hills in Wales at or above 500m in height with 15m minimum drop.  Accompanying the main list are three sub lists, these are; 500m Sub-Uchaf, 490m Sub-Uchaf and the Double Sub category, with this hill being reclassified to 500m Sub-Uchaf status, the criteria for which are all Welsh hills at or above 500m in height with 14m or more and below 15m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams with the Introduction to the list being published on Mapping Mountains in November 2015 and an update relating to the list appearing on Mapping Mountains on the 19^th June 2019.

The name the hill is listed by is Moel Darren and it is adjoined to the Carnedd y Filiast group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A2), and it is positioned with the A5 road to its north-east, the B4501 road to its west and the A494 road to its south-east, and has the town of Y Bala towards the south south-west and the village of Cerrigydrudion towards the north.

This hill was not included in the original list of Welsh 500m P15s that later became known as Yr Uchafion and latterly as The Welsh Highlands – Uchafion Cymru, however it was listed as a potential qualifying hill as it has a 509m summit spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps and bwlch contouring between 490m – 500m.

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

This hill was subsequently surveyed using a basic levelling staff on the 1^st May 2004 by Myrddyn Phillips, resulting in a 51½ft / 15.7m drop value, which was sufficient for it to be classified as an Uchaf.

However, as the margin of uncertainty applicable to the basic levelling method of surveying over the distance between bwlch and summit and the terrain of this hill is approximately +/- 1m, the hill was prioritised for an accurate survey.

The Trimble GeoXH 6000 gathering data at the summit of Moel Darren

The Trimble GeoXH 6000 gathering data at the bwlch of Moel Darren

Therefore, the reclassification of Moel Darren to 500m Sub-Uchaf status is due to a survey with the Trimble GeoXH 6000, resulting in a 510.0m summit height and a 495.4m bwlch height, with these values giving this hill 14.6m of drop which is insufficient for it to be retained as an Uchaf.

The full details for the hill are:

Group:  CCarnedd y Filiast

Name:  Moel Darren

OS 1:50,000 map:  125

Summit Height:  510.0m (converted to OSGM15)

Summit Grid Reference:  SH 95221 41372

Bwlch Height:  495.4m (converted to OSGM15)

Bwlch Grid Reference:  SH 95185 41686

   

Drop:  14.6m 

For the additions, deletions and reclassifications to The Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

The Welsh 500m P15s (Yr Uchafion)

The Welsh 500m P15s (Yr Uchafion) – 500m Subs

The Welsh 500m P15s (Yr Uchafion) – 490m Subs

The Welsh 500m P15s (Yr Uchafion) – Double Subs

Aled Williams and Myrddyn Phillips (June 2020)