Foel Fawr (SH 728 392)
There has been a Summit Relocation to a hill that
is listed in the 500m Twmpau and The Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height
and their locations, the drop and status of the hill confirmed by a Trimble
GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams on the 19th
July 2020.
Foel Fawr (SH 728 392) |
The criteria for the two listings that this summit
relocation applies to are:
500m Twmpau – Welsh hills at or above
500m and below 600m in height that have 30m minimum drop, with an accompanying
sub category entitled the 500m Sub-Twmpau consisting of all Welsh hills at or
above 500m and below 600m in height that have 20m or more and below 30m of
drop. With the word Twmpau being an
acronym standing for thirty welsh metre prominences and upward. The list is authored by Myrddyn Phillips and is published on Mapping Mountains in Google Doc format.
The 500m Twmpau by Myrddyn Phillips |
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. 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 Welsh Highlands - Uchafion Cymru by Myrddyn Phillips and Aled Williams |
The name the hill is listed by is Foel Fawr and it is adjoined to the Arenig group
of hills, which are situated in the central
part of North Wales (Region A, Sub-Region A3), and it is positioned with the B4391
road to its north, the A470 road to its west and the A4212 road to its south,
and has the village of Trawsfynydd towards the south-west.
When the original list of Welsh 500m P15s that
later became known as Yr Uchafion and
latterly as The Welsh Highlands –
Uchafion Cymru was first compiled, this hill was listed with an estimated c
41m of drop based on the 528m summit spot height that appears on the Ordnance
Survey 1:25,000 Explorer map and which is positioned at SH 726 394, and an
estimated c 487m bwlch height.
Extract from the Ordnance Survey 1:25,000 Explorer map |
Since first compilation of the Welsh 500m P15 list
there have been a number of Ordnance Survey maps made available online, some of
these are historic such as the series of Six-Inch maps on the National Library
of Scotland website, whilst others are current and digitally updated such as
the Ordnance Survey Vector Map Local that was hosted on the Geograph website
and which was entitled the Interactive Coverage Map, and it was this map that
showed a 528m map heighted twin summit positioned at SH 728 392. The two 528m spot heights are also shown on
the mapping hosted on the Magic Maps website.
Extract from the Magic Maps website |
However, it was not until the survey with the
Trimble GeoXH 6000 that the details for this hill could be accurately
re-assessed. The height and position for
each summit is given below:
South-easterly summit: 528.611m at SH 72872 39284
North-westerly summit: 527.542m at SH 72621 39476
The above detail compared to the prioritised
summit previously given comes
within the parameters of the Summit Relocations used within this page heading,
these parameters are:
The term Summit Relocations applies when the
hill’s high point is found to be positioned; in a different field, to a
different feature such as in a conifer plantation, placed within a different
map contour, to a different point where a number of potential summit positions
are within close proximity, or when natural ground or the natural and intact
summit of a hill is confirmed compared to a higher point such as a raised field
boundary that is judged to be a relatively recent man-made construct, or 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.
Gathering data at the higher of the Foel Fawr summits |
Gathering data at the lower of the Foel Fawr summits |
Therefore, the summit height produced by the
Trimble GeoXH 6000 survey is 528.6m and this is positioned at SH 72872 39284, this position is not given
a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000
Explorer maps, but is given a 528m spot height on the mapping hosted on the
Magic Maps website, and is approximately 260 metres south-eastward from where
the previously prioritised listed summit is positioned.
The full details for the hill are:
Group: Arenig
Name: Foel Fawr
OS 1:50,000 map: 124
Summit Height: 528.6m
(converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference (new position): SH 72872 39284 (Trimble GeoXH 6000)
Bwlch Height: 485.5m (converted
to OSGM15, Trimble GeoXH 6000)
Bwlch Grid Reference:
SH 73074 39525 (Trimble GeoXH 6000)
Drop: 43.1m (Trimble
GeoXH 6000 summit and bwlch)
Myrddyn Phillips and Aled Williams (October 2020)
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