Pen Las Rock (SH 208 815) – Welsh P15 addition
There has been an addition to the list of The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data.
The criteria for the list that this addition applies to are:
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was not included in either the main P15 list or the accompanying P14 sub list, as the contours that appear on the Ordnance Survey 1:25,000 Explorer map are hard to decipher.
Extract from the Ordnance Survey 1:25,000 Explorer map |
The details for this hill were re-assessed against the large scale mapping that has replaced the Ordnance Survey mapping available on the Geograph website and the interactive mapping available of the Magic Maps website. The former gives this hill a 50m summit spot height and the latter a 49m summit spot height. The 50m spot height compliments 5m contouring available online, with this also giving bwlch contouring between 30m – 35m and which has been estimated as c 33m in height.
Extract from the Ordnance Survey mapping hosted on the Geograph website |
The full details for the hill are:
Group: Ynys Môn
Name: Pen Las Rock
OS 1:50,000 map: 114
Summit Height: 50m (spot height)
Summit Grid Reference: SH 20813 81594 (spot height)
Bwlch Height: c 33m (interpolation)
Bwlch Grid Reference: SH 20829 81624 (interpolation)
Drop: c 17m (spot height summit and interpolated bwlch)
Myrddyn Phillips
(October 2021)
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