Bryn y Fedwen (SJ 115 125)
There has been a Significant Name Change to a hill that is listed in the 100m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.
LIDAR image of Bryn y Fedwen (SJ 115 125) |
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.
The 100m Twmpau by Myrddyn Phillips |
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 it was considered not to meet the criteria then used for this sub category.
After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed under the point (Pt. 157m) notation with an estimated c 20m of drop, based on the 157m summit spot height and an estimated c 137m bwlch height, with the latter based on interpolation of 10m contouring between 130m – 140m that appear on the Ordnance Survey 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the Tithe map |
Extract from the apportionments |
The full details for the hill are:
Group: Y Berwyn
Name: Bryn y Fedwen
Previously Listed Name: Pt. 157m
OS 1:50,000 map: 125
Summit Height: 156.8m
(converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference:
SJ
11582 12548 (Trimble GeoXH 6000)
Bwlch Height:
134.9m (LIDAR)
Bwlch Grid Reference:
SJ 11523 12758 (LIDAR)
Drop: 21.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Myrddyn Phillips (July
2021)
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