Pt. 577m (SN 808 768) – 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.
As the authors do not know an appropriate name for the hill
either from historic research or from local enquiry it is being listed by the
point (Pt. 577m) notation, and it is adjoined to the Elenydd group of hills, which are situated in the northern part of Mid
and West Wales (Region B, Sub-Region B2), and it is positioned with the A44
road to its north, the A4120 road to its west, the B4574 road to its
south-west, a minor road to its south and the A470 road to its east, and has
the village of Pontarfynach (Devil’s Bridge) towards the west.
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 577m summit spot height and bwlch contouring between 560m – 570m that
appear on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map its
interpolated drop value was judged insufficient for 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
the mapping on the OS Maps website. 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 bwlch contouring between 560m – 565m, with interpolation giving an
estimated bwlch height of c 563m.
 |
| Extract from the OS Maps website |
Therefore, the addition of this hill to 500m
Sub-Uchaf status is due to detail on contemporary maps produced from Ordnance
Survey data, resulting in a 577m summit height and an estimated c 563m 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: Elenydd
Name: Pt. 577m
OS 1:50,000 map: 135,
136, 147
Summit Height: 577m
(spot height)
Summit Grid Reference:
SN 80889 76890 (spot height)
Bwlch Height: c 563m
(interpolation)
Bwlch Grid Reference:
SN 80536 77083 (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 (August 2020)
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