Woodlake Park (ST 343
997)
There has been a Significant Height Revision to a
hill that is listed in the 100m Twmpau and
Y Trechol – The Dominant Hills of Wales,
with the summit height, bwlch height and their locations, the drop and status
of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.
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| LIDAR image of Woodlake Park (AT 343 997) |
The criteria for the two listings that this height
revision applies to are:
100m Twmpau - Welsh hills at or above 100m and below 200m in height with 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.
Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose
prominence equal or exceed half that of their absolute height. With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose
prominence is between one third and half that of their absolute height. The list is authored by Myrddyn Phillips with
the Introduction to the start of the Mapping Mountains publication of this list
appearing on the 3rd December 2015.
The name the hill is listed by is Woodlake Park
and it is adjoined to the Cymoedd Gwent group of hills, which are situated in
the eastern part of South Wales (Region C, Sub-Region C2), and it is positioned
above the Llandegfedd Reservoir which is to its west, and has the town of
Pont-y-pŵl
(Pontypool) towards its west and Brynbuga (Usk) towards its east.
When the original Welsh 100m P30 list was
published on Geoff Crowder’s v-g.me website this hill was listed with a 147m
summit height, based on the spot height positioned at ST 340 994 that appears
on the Ordnance Survey 1:50,000 Landranger map, with the 1:25,000 Explorer map
having no spot height.
The details for this hill were re-evaluated when
the Ordnance Survey Vector Map Local hosted on the Geograph website and which
is entitled the Interactive Coverage Map became available online, and as this
map gives a 149m spot height positioned at ST 34341 99786, the summit of this
hill was relocated.
 |
| Extract from the Ordnance Survey Vector Map Local hosted on the Geograph 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.
The height produced by LIDAR analysis is 150.7m positioned
at ST 34335 99793, this is not a
substantial revision compared to some revised heights, but it does come within
the parameters of the Significant Height Revisions used within this page
heading, these parameters are:
The term Significant Height Revisions applies to
any listed hill whose interpolated height and Ordnance Survey or Harvey map
summit spot height has a 2m or more discrepancy when compared to the survey
result produced by the Trimble GeoXH 6000 or analysis of data produced via
LIDAR, also included are hills whose summit map data is missing an uppermost
ring contour when compared to the data produced by the Trimble or by LIDAR
analysis.
Therefore, this hill’s new listed summit height is
150.7m and this was derived from LIDAR analysis, this is 1.7m higher than the previously
listed summit height of 149m which was derived from the spot height that
appears on the Ordnance Survey Vector Map Local hosted on the Geograph website.
The full details for the hill are:
Group: Cymoedd Gwent
Name: Woodlake Park
OS 1:50,000 map: 171
Summit Height (New height):
150.7m (LIDAR)
Summit Grid Reference:
ST 34335 99793 (LIDAR)
Bwlch Height: 91.5m
(LIDAR)
Bwlch Grid Reference:
ST 33405 01033 (LIDAR)
Drop: 59.3m (LIDAR)
Dominance: 39.31%
Myrddyn Phillips (August 2019)
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