Moel y Gadair (SH 521 391) 30-99m Twmpau reclassified to 30-99m Sub-Twmpau
There has been a reclassification to the listing of Twmpau (thirty welsh metre prominences and upward) hills due to a recent survey with the Trimble GeoXH 6000. The hill is listed in the 30–99m height band of Twmpau hills and is situated to the south-west of the small community of Pentrefelin, which is situated between Porthmadog to the east and Cricieth to the south-west.
There has been a reclassification to the listing of Twmpau (thirty welsh metre prominences and upward) hills due to a recent survey with the Trimble GeoXH 6000. The hill is listed in the 30–99m height band of Twmpau hills and is situated to the south-west of the small community of Pentrefelin, which is situated between Porthmadog to the east and Cricieth to the south-west.
The hill has been reclassified from a P30 Twmpau to a
Sub-Twmpau, and re-joins these ranks after being originally listed in the ‘Hills
to Survey’ Sub-List that appeared on Geoff Crowder’s v-g.me website. On subsequent reassessment the hill was
promoted to full P30 status due to bwlch contour interpolation, with a
drop value of c 30m based on a summit spot height of 67m and an estimated bwlch
height of c 37m.
The hill is named Moel y Gadair and its summit was
surveyed with the Trimble GeoXH 6000 on the 15th June 2015 giving a
height of 66.7m (converted to OSGM15). On that day I misinterpreted
the bwlch contouring and therefore took a number of data sets from the
incorrect place. Having re-examined
Ordnance Survey mapping and driven a Google Car on the A 497 which passes over
this bwlch I was confident that I now knew where the critical bwlch was
positioned.
The subsequent survey of this hill’s bwlch
resulted in a height value of 38.1m (converted to OSGM15), giving the hill insufficient drop to
retain its P30 Twmpau status.
The full details for the hill are:
Cardinal Hill: Moel
Hebog
Summit Height: 66.7m (converted to OSGM15)
Name: Moel y Gadair
OS 1:50,000 map: 124
Summit Grid Reference:
SH 521 391
Drop: 28.5m (converted to OSGM15)
 |
| Moel y Gadair (SH 521 391) now reclassified from a P30 Twmpau to a Sub-Twmpau with 28.5m of drop |
For details on the survey that reclassified this hill from P30
Twmpau to Sub-Twmpau status please click {here} for summit and {here} for the
bwlch survey.
Myrddyn Phillips (February 2016)
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