Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru

Pt. 505.8m (SN 785 598) – Welsh Highland Sub 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 LIDAR analysis conducted by Aled Williams. 

LIDAR image of Pt. 505.8m (SN 785 598)

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 hill is being listed by the point (Pt. 505.8m) notation and it is adjoined to the Esgair Wen group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its north-west and south, and has the small community of Pontrhydfendigaid towards the north-west and the town of Tregaron towards the west. 

Extract from the Ordnance Survey series of Six-Inch maps

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 9m of drop, based on the 1649ft (502.6m) height that appeared on the Ordnance Survey series of Six-Inch maps and an estimated c 494m bwlch height, based on interpolation of 5m contouring that appeared on online mapping. 

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

The height that appeared on the Ordnance Survey series of Six-Inch maps was at odds with the 506m spot height that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and which is positioned at SN 78576 59903, however this spot height was not supported by contemporary contour information on large scaled Ordnance Survey maps. 

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 addition of this hill to Welsh Highland Sub status is due to LIDAR analysis, resulting in a 505.8m summit height and a 492.4m bwlch height, with these values giving this hill 13.5m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Esgair Wen

Name:  Pt. 505.8m

OS 1:50,000 map:  146, 147

Summit Height:  505.8m (LIDAR)

Summit Grid Reference:  SN 78575 59899 (LIDAR)

Bwlch Height:  492.4m (LIDAR)

Bwlch Grid Reference:  SN 78513 60070 (LIDAR)   

Drop:  13.5m (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 (November 2023)