Sunday, 18 December 2016

Mapping Mountains – Hill Reclassifications – Y Pedwarau

Pt. 415.6m (SO 243 011) - 400m Sub-Pedwar reclassified to Pedwar

There has been a reclassification to the listing of Y Pedwarau with a 400m Sub-Pedwar being promoted to the ranks of Pedwar by analysis of LIDAR data by Aled Williams.  Y Pedwarau are all hills in Wales at or above 400m and below 500m in height that have a minimum drop of 30m.  The hill was first analysed with LIDAR data by Joseph Nuttall who on my request had looked at this hill and sent the details to me.  Independent of this, Aled also analysed LIDAR data using a slightly different method and confirmed this hill’s inclusion.

The hill is situated in the group of hills known as the Y Cymoedd with its Cardinal Hill being Mynydd Coety (SO 231 079) and is placed in the Region of South Wales (C2).  The hill is positioned between the towns of Pont-y-pŵl (Pontypool) to its east and Abertyleri (Abrtillery) to its north north-west, with its summit positioned above the head of the valleys comprising the Nant Ffrwd-oer and the Nant y Caws.  The hill can be accessed from the Blaen-y-cwm Road to its south-west where a track leads round the south, east and then north of the summit, the high point of the hill is in a conifer plantation but is not difficult to get to.

As the authors have not found an appropriate name for the hill the Point (Pt. 415.6m) notation is being used.  The hill is the relic of mine spoil and is therefore man-made, with old Ordnance Survey maps showing a continuous decline from the summit of the higher adjacent Mynydd Llanhiledd without any contours for where this hill is now found.

The hill was listed as a 400m Sub-Pedwar based on the 416m summit spot height on the Ordnance Survey enlarged mapping hosted on the Geograph website and an interpolated height for the connecting bwlch of c 388m, based on bwlch contouring between 380m – 390m.

Aled’s analysis of LIDAR data gives the hill the following details:

Pt. 415.6m

Summit Height:  415.6m

Summit Grid Reference:  SO 24354 01195

Bwlch Height:  384.2m

Bwlch Grid Reference:  SO 24535 01192

Drop:  31.4m

Therefore, the 415.6m LIDAR data produced for the summit position at SO 24354 01195 and the 384.2m LIDAR data produced for the bwlch position at SO 24535 01192 is sufficient for this hill to be included as a Pedwar with 31.4m of drop, and therefore Pt. 415.6m is included in the listing of the Y Pedwarau and the list will be updated accordingly.

The full details for the hill are:

Cardinal Hill:  Mynydd Coety

Summit Height:  415.6m (LIDAR data)

Name:  Pt. 415.6m

OS 1:50,000 map:  171

Summit Grid Reference:  SO 24354 01195 

Drop:  31.4m (LIDAR data)

This now brings the overall total for the Y Pedwarau to 446 hills with six additions, and seven reclassifications to 400m Sub-Pedwar since publication of the list by Europeaklist in May 2013.  The hill will be taken out of the 400m Sub-Pedwar list and added to the main list in forthcoming publications.  The list of Pedwar hills is available from the Haroldstreet website (January 2014) with all subsequent changes available via the Mapping Mountains site.

The list of additions and reclassifications from the Pedwar list since the 1st edition of the Y Pedwarau was published by Europeaklist are as follows:


Pt. 415.6m (LIDAR data) (SO 243 011) 400m Sub-Pedwar reclassified to Pedwar with 31.4m drop


Myrddyn Phillips and Aled Williams (December 2016)

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