Mapping Mountains – Hill Reclassifications – The Welsh P15s

 

Pt. 357.3m (SN 995 612) – Welsh P15 reclassified to Welsh Sub-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 Pt. 357.3m (SN 995 612)

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 hill is being listed by the point (Pt. 357.3m) 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 Drygarn Fawr group of hills, which are situated in the central part of the South Wales Region (Region B, Sub-Region B1), and it is positioned with a minor road to its immediate west and the A470 road to its north-east, and has the town of Llandrindod Wells towards the east.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main P15 list with 15m of drop, based on the 358m summit spot height and the 343m 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.

Therefore, the reclassification of this hill to Welsh Sub-P15 status is due to LIDAR analysis, resulting in a 357.3m summit height and a 342.9m bwlch height, with these values giving this hill 14.4m of drop, which is insufficient for it to be included in the main list of The Welsh P15s. 

 

The full details for the hill are: 

Group:  Drygarn Fawr 

Name:  Pt. 357.3m 

OS 1:50,000 map:  147

Summit Height:  357.3m (LIDAR)                                                           

Summit Grid Reference:  SN 99517 61281 (LIDAR) 

Bwlch Height:  342.9m (LIDAR) 

Bwlch Grid Reference:  SN 99418 61379 (LIDAR) 

Drop:  14.4m (LIDAR) 

 

Myrddyn Phillips (January 2023)