Bryn Crugog (SN 941 923) – 400m Sub-Pedwar reclassified to Pedwar
There has been a reclassification to the listing of Y Pedwarau due to analysis of LIDAR data
by Aled Williams. Y Pedwarau is the title for the list of 400m hills of Wales and
takes in all Welsh hills at or above 400m and below 500m in height that have a
minimum 30m of drop, the list is a joint compilation between Myrddyn Phillips
and Aled Williams and it commenced publication on Mapping Mountains on the
30.01.17.
Accompanying the main Y
Pedwarau list are five categories of sub hills, with this hill being
reclassified from a 400m Sub-Pedwar to
a Pedwar.
The criteria for 400m
Sub-Pedwar qualification is all Welsh hills at or above 400m and below 500m
in height with 20m or more and below 30m of drop.
Prior to analysis of LIDAR data the hill was
listed with c 20m of drop based on the 447m summit spot height that appears on
the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an
estimated bwlch height of c 427m based on interpolation of bwlch contouring
between 420m – 430m. The
reclassification of this hill is dependent upon the analysis of LIDAR data for
it, and its adjacent north-westerly hill of Esgair
Hir (SN 937 925), with the height of the highest hill swapping, with this
affecting the position of the critical bwlch of both hills and their
status. The Hill Reclassifications post
for Esgair Hir will appear
separately.
The hill is situated in the Pumlumon range with its
Cardinal Hill being Bryn Amlwg (SN
921 973) and is placed in the Region
of Mid and West Wales (Region B, Sub-Region B2), and is positioned with the
small community of Llawr-y-glyn to
the south-west.
As the summit is not a part of designated open
access land permission to visit should be sought, however there is a public footpath
that approaches from the east and heads just south of the high point of the
hill.
The name of the hill is Bryn Crugog and its reclassification from 400m Sub-Pedwar to Pedwar is
due to the analysis of LIDAR data by Aled Williams. LIDAR (Light Detection & Ranging) is highly
accurate height data that is now freely available for much of England and
Wales.
Aled’s analysis of LIDAR data gives the hill the
following details:
Bryn Crugog
Summit Height: 446.7m
Summit Grid Reference: SN 94130 92357
Bwlch Height: 394.7m
Bwlch Grid Reference: SN 93185 93490
Drop: 52.0m
Therefore, the 446.7m LIDAR data produced for the summit
position at SN 94130 92357 and the 394.7m LIDAR data
produced for the bwlch position at SN 93185 93490 gives
this hill 52.0m of drop which is sufficient for its reclassification to a Pedwar.
The full details for the hill are:
Cardinal Hill: Bryn
Amlwg
Summit Height: 446.7m (LIDAR
data)
Name: Bryn Crugog
OS 1:50,000 map: 136
Summit Grid Reference:
SN 94130 92357
Drop: 52.0m (LIDAR
data)
This reclassification now brings the total for Y Pedwarau to 443 hills with nine
additions, and thirteen reclassifications to 400m Sub-Pedwar status since publication of the list by
Europeaklist in May 2013.
The overall total for the 400m
Sub-Pedwarau is now 217 with 22 hills being added and 18 hills being taken
out of this category since publication of the list by Europeaklist in May 2013.
The list of Pedwar
hills is available from the Haroldstreet website (January 2014) with all
subsequent changes detailed on the Mapping Mountains site, with the list also
having commenced publication on Mapping Mountains on the 30.01.17.
For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains
since the May 2013 publication of the list by Europeaklist please consult the
following Change Registers:
Myrddyn Phillips and Aled Williams (June 2017)
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