Carreg Gwalch (SH 642 552) – 500m
Sub-Uchaf addition
There has been an addition to the listing of The Welsh Highlands – Uchafion Cymru, 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 Highlands –
Uchafion Cymru
– This is the revised draft title for the Welsh 500m P15s list that takes
in all hills in Wales at or above 500m in height with 15m minimum drop. Accompanying the main list are three sub
lists, these are; 500m Sub-Uchaf, 490m Sub-Uchaf and the Double Sub category,
with this hill being added as a 500m Sub-Uchaf.
The criteria for which are all Welsh hills at or above 500m in height
with 14m or more and below 15m of drop.
The list is co-authored by Myrddyn Phillips and Aled Williams with the Introduction to the list being published on Mapping Mountains in November 2015 and an update relating to the list appearing on Mapping Mountains on the 19th June 2019.
The name the hill is listed
by is Carreg Gwalch and it is adjoined to the Yr Wyddfa group of hills, which are situated in the north-western part of
North Wales (Region A, Sub-Region A1), and it is positioned with the A4086 road to its north and the A498 to
its south-east, and has the village of Capel Curig towards the east north-east.
This hill was not included as a P14 Sub in the
original list of Welsh 500m P15s that later became known as Yr Uchafion and latterly as The Welsh Highlands – Uchafion Cymru, as
with a 545m summit spot height and bwlch contouring between 530m – 540m that appear
on the Ordnance Survey 1:25,000 Explorer map, interpolation suggested that it
did not have sufficient drop to be considered for P14 500m Sub-Uchaf status.
 |
| Extract from the Ordnance Survey 1:25,000 Explorer map |
Since the original compilation of this list there
are now a number of interactive maps originated from Ordnance Survey data that
are available online. One of these is
available on the Magic Maps website, and it is this map that gives this hill a
summit spot height of 546m.
 |
| Extract from the Magic Maps website |
Another resource now available online is the
WalkLakes website which hosts an interactive map originated from the Ordnance
Survey Open Data programme. This map has
many spot heights not on other publicly available Ordnance Survey maps and for
this hill it also shows a 546m summit spot height which is positioned at SH 64236
55249.
 |
| Extract from the WalkLakes website |
The details for this hill were also re-assessed
when the OS Maps website became available online. This is the replacement for OS Get-a-map and
has contours at 5m intervals which are proving consistently more accurate
compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000
Explorer maps and used to appear on the online Vector Map Local. This mapping has an uppermost 545m ring contour
and bwlch contouring between 530m – 535m, with interpolation giving an
estimated bwlch height of c 532m.
 |
| Extract from the OS Maps website |
Therefore, the addition of Carreg Gwalch to 500m
Sub-Uchaf status is due to detail on contemporary maps produced from Ordnance
Survey data, resulting in a 546m summit height and an estimated c 532m bwlch
height, with these values giving this hill c 14m of drop, which is sufficient
for it to be classified as a 500m Sub-Uchaf.
The full details for the hill are:
Group: Yr Wyddfa
Name: Carreg Gwalch
OS 1:50,000 map: 115
Summit Height: 546m (spot
height)
Summit Grid Reference:
SH 64236 55249 (spot height)
Bwlch Height: c 532m (interpolation)
Bwlch Grid Reference:
SH 64226 55161 (interpolation)
Drop: c 14m (spot
height summit and interpolated bwlch)
For the additions, deletions and reclassifications to The Welsh Highlands – Uchafion Cymru
reported on Mapping Mountains please consult the following Change Registers:
Aled Williams and Myrddyn Phillips (July 2020)
No comments:
Post a Comment