Mapping Mountains – Hill Reclassifications – The Welsh P15s

 

Cae Cwar y Tŷ (SN 907 499) – Welsh Sub-P15 reclassified to Welsh P15 

There has been a reclassification to the list of The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Cae Cwar y Tŷ (SN 907 499)

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

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is now listed by is Cae Cwar y Tŷ, and this was derived from the Tithe map, and it is adjoined to the Drygarn Fawr group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with the A483 road to its north and a minor road to its south-west and east, and has the town of Llanwrtyd towards the south-west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the accompanying sub list with 14m of drop, based on the 257m summit spot height and the 243m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

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

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

Therefore, the reclassification of this hill from Welsh Sub-P15 status is due to LIDAR analysis, resulting in a 259.0m summit height and a 243.4m bwlch height, with these values giving this hill 15.6m 0f drop, which is sufficient for it to be classified as a Welsh P15. 

 

The full details for the hill are: 

Group:  Drygarn Fawr 

Name:  Cae Cwar y Tŷ 

OS 1:50,000 map:  147

Summit Height:  259.0m (LIDAR)                                                           

Summit Grid Reference:  SN 90705 49957 (LIDAR)                                                  

Bwlch Height:  243.4m (LIDAR) 

Bwlch Grid Reference:  SN 90715 49674 & SN 90716 49675 (LIDAR) 

Drop:  15.6m (LIDAR) 

 

Myrddyn Phillips (March 2025)