Comin Gwauncaegurwen (SN 738 129) – 100m Sub-Twmpau addition
There has been an addition to the list of 100m Twmpau, 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 Comin Gawuncaegurwen (SN 738 129) |
The criteria for the list that this addition
applies to are:
100m Twmpau
– Welsh hills at or above
100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m
Sub-Twmpau with the criteria for this sub category being all Welsh hills at or
above 100m and below 200m in height with 20m or more and below 30m of drop,
with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
100m Twmpau by Myrddyn Phillips |
The name the hill is listed by is Comin
Gwauncaegurwen and this was derived from the Tithe map with the language
protocol also instigated, and it is adjoined to the Mynydd Du group of hills, which
are situated in the southern part of South
Wales (Region B, Sub-Region B5), and
it is positioned with the A4068 road to its north-east, the A4069 road to its
west and a minor road to its south-east, and has the village of Brynaman
towards the west north-west.
Extract from the Ordnance Survey 1:50,000 Landranger map |
When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not
included in the Hills to be surveyed
sub list, as with no significant contours of note on the Ordnance Survey
1:50,000 Landranger and 1:25,000 Explorer map it was difficult to know whether
any hill of note existed.
Extract from the Ordnance Survey 1:25,000 Explorer map |
Since the original publication of the Welsh P30
lists on Geoff Crowder’s v-g.me website there have been a number of maps made
available online. Some of these are
historic such as the series of Six-Inch maps on the National Library of
Scotland website. Whilst others were digitally
updated such as the Ordnance Survey Vector Map Local that was hosted on the
Geograph website and which was entitled the Interactive Coverage Map, whilst
others are current and digitally updated such as the interactive mapping on the
Magic Maps and WalkLakes websites.
One of the mapping resources now available online
is the WalkLakes website which hosts an interactive map originated from the
Ordnance Survey Open Data programme.
This map has many spot heights not on other publicly available maps and
an uppermost 200m ring contour is given on the summit area of this hill.
Extract from the interactive mapping hosted on the WalkLakes website |
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 100m
Sub-Twmpau status is due to LIDAR analysis, resulting in a 196.6m summit height
and a 174.7m bwlch height, with these values giving this hill 21.8m of drop,
which is sufficient for it to be classified as a 100m Sub-Twmpau.
The full details for the hill are:
Group: Mynydd Du
Name: Comin Gwauncaegurwen
OS 1:50,000 map: 160
Summit Height: 196.6m (LIDAR)
Summit Grid Reference: SN 73812 12929 (LIDAR)
Bwlch Height: 174.7m (LIDAR)
Bwlch Grid Reference: SN 73776 13436 (LIDAR)
Drop: 21.8m (LIDAR)
Myrddyn Phillips
(September 2024)
No comments:
Post a Comment