Maes Llwyn (SH 435 920)
There has been a Summit Relocation to a hill that is listed in the The Welsh P15s, 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 Maes Llwyn (SH 435 920) |
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 listed with 25m of drop, based on the 77m summit spot height positioned at SH 43598 92043 on or near to a covered reservoir, that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and the 52m bwlch spot height that appears on the Ordnance Survey 1:50,000 Landranger map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Maes Llwyn (SH 435 920) |
The term Summit Relocations applies when the hill’s high point is found to be positioned; in a different field, within a different map contour, to a different feature such as in a conifer plantation, to a different point where a number of potential summit positions are within close proximity, a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.
Therefore, the summit height produced by LIDAR analysis is 74.0m and this is positioned at SH 43593 92022, this position is not given a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and is approximately 20 metres southward from where the 77m spot height appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.
The full details for the hill are:
Group: Ynys Môn
Name: Maes Llwyn
OS 1:50,000 map: 114
Summit Height: 74.0m (LIDAR)
Summit Grid Reference (New Position): SH 43593 92022 (LIDAR)
Bwlch Height: 54.9m (LIDAR)
Bwlch Grid Reference: SH 43658 91747 (LIDAR)
Drop: 19.1m (LIDAR)
Myrddyn Phillips
(September 2021)
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