Saturday, 16 December 2023

Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru


Esgair Neint (SN 785 801) – 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 Esgair Neint (SN 785 801)

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 Esgair Neint and it is adjoined to the Y Garn group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B1), and it is positioned with the A44 road to its north-west, and the B4343 road and the A4120 road to its west, and has the village of Ponterwyd towards the west north-west.

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 10m of drop, based on a 532m summit height and an estimated c 522m bwlch height, with the latter based on interpolation of 5m contouring that appeared on online mapping. 

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

When the details for this hill were updated with data from basic levelling surveys conducted by Myrddyn Phillips, the drop was amended to 9.9m, based on a 32½ft/9.9m basic levelling survey conducted on the 24.09.04.

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 535.5m summit height and a 525.5m 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:  Y Garn

Name:  Esgair Neint

OS 1:50,000 map:  135

Summit Height:  535.5m (LIDAR)

Summit Grid Reference:  SN 78508 80178 (LIDAR)

Bwlch Height:  525.5m (LIDAR)

Bwlch Grid Reference:  SN 78586 80342 (LIDAR)   

Drop:  10.0m (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 (December 2023) 

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