Foel Ddu (SN 852 799) – 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 Foel Ddu (SN 852 799) |
The criteria for the list that this addition applies to are:
|
Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips |
The name the hill is listed by is Foel Ddu 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-east and a minor road to its south-east, and has the village
of Llangurig towards the east.
When the initial P10 sub list was completed in
June 2020 this hill was listed with an estimated c 8m of drop, based on an estimated
c 530m summit height and an estimated c 522m bwlch height, with both heights based
on interpolation of 5m contouring that appeared on online mapping, with an
accompanying note stating; Paper OS maps
give a summit height of 532m, which isn't supported by contour data on the
enlarged-scale online OS 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 532.1m summit
height and a 520.9m bwlch height, with these values giving this hill 11.2m 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: Foel Ddu
OS 1:50,000 map: 135,
136, 147
Summit Height: 532.1m
(LIDAR)
Summit Grid Reference:
SN 85278 79929 (LIDAR)
Bwlch Height: 520.9m
(LIDAR)
Bwlch Grid Reference:
SN 85005 79801 (LIDAR)
Drop: 11.2m
(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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