Foel Fawr (SH 679 057)
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, 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 Foel Fawr (SH 679 057) |
Y Trichant
– The 300m Hills of Wales – Welsh
hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the
Sub-Trichant, with the criteria for this sub category being all Welsh hills at
or above 300m and below 400m in height with 20m or more and below 30m of drop. The
list is authored by Myrddyn Phillips with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017,
and the Introduction to the Mapping Mountains publication of the list appearing
on the 1st January 2022.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed with a 348m summit height based on the spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Foel Fawr (SH 679 057) |
The term Significant Height Revisions applies to any listed hill whose interpolated summit 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, the new listed summit height of this
hill is 343.9m and this was derived from LIDAR analysis, this is 4.1m lower than
the previously listed summit height of 348m which appears as a spot height on
the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.
The full details for the hill are:
Group: Tarren y Gesail
Name: Foel Fawr
OS 1:50,000 map: 124
Summit Height (New Height): 343.9m (LIDAR)
Summit Grid Reference: SH 67982 05743 (LIDAR)
Bwlch Height: 286.5m (LIDAR)
Bwlch Grid Reference: SH 67651 05532 (LIDAR)
Drop: 57.4m (LIDAR)
Myrddyn Phillips (March
2022)
No comments:
Post a Comment