Tuesday, 13 June 2017

Mapping Mountains – Hill Reclassifications – Y Pedwarau


Coed yr Artsh (SN 764 760) – 400m Sub-Pedwar addition

There has been an addition to the listing of Y Pedwarau due to analysis of LIDAR data by Aled Williams.  Y Pedwarau is the title for the list of 400m hills of Wales and takes in all Welsh hills at or above 400m and below 500m in height that have a minimum 30m of drop, the list is a joint compilation between Myrddyn Phillips and Aled Williams and it commenced publication on Mapping Mountains on the 30.01.17.

Accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar categoryThe criteria for 400m Sub-Pedwar qualification is all Welsh hills at or above 400m and below 500m in height with 20m or more and below 30m of drop.

Prior to analysis of LIDAR data the hill was not classified, but it was catalogued with c 18m of drop based on the 444m summit spot height on the Ordnance Survey enlarged mapping hosted on the Geograph website and an estimated bwlch height of c 426m based on interpolation of bwlch contouring between 420m – 430m.

The hill is situated in the Elenydd range with its Cardinal Hill being Pen y Garn (SN 798 771) and is placed in the Region of Mid and West Wales (Region B, Sub-Region B2), and is positioned with the small community of Pontarfynach (Devil’s Bridge) to the west north-west and Cwmystwyth to the south-east.

The hill is not a part of designated open access land and therefore permission to visit should be sought, however it is a part of a large conifer forest that has many designated forest walks in it, and according to Ordnance Survey maps a path leaves one of these walks and heads through to trees to the summit, if this path exists on the ground those wishing to visit may have a relatively easy route to the hill’s high point.

The name of the hill is Coed yr Artsh and its addition to 400m Sub-Pedwar status is due to the analysis of LIDAR data by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

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


Coed yr Artsh

Summit Height:  443.5m

Summit Grid Reference:  SN 76472 76079

Bwlch Height:  422.0m

Bwlch Grid Reference:  SN 76593 76052

Drop:  21.5m


Therefore, the 443.5m LIDAR data produced for the summit position at SN 76472 76079 and the 422.0m LIDAR data produced for the bwlch position at SN 76593 76052 gives this hill 21.5m of drop which is sufficient for its inclusion as a 400m Sub-Pedwar.


The full details for the hill are:

Cardinal Hill:  Pen y Garn

Summit Height:  443.5m (LIDAR data)

Name:  Coed yr Artsh

OS 1:50,000 map:  135, 147

Summit Grid Reference:  SN 76472 76079

Drop:  21.5m (LIDAR data)


The total for Y Pedwarau remains at 442 hills with nine additions, and fourteen reclassifications to 400m Sub-Pedwar status since publication of the list by Europeaklist in May 2013.

The overall total for the 400m Sub-Pedwarau is now 220 with 25 hills being added and 18 hills being taken out of this category since publication of the list by Europeaklist in May 2013.

The list of Pedwar hills is available from the Haroldstreet website (January 2014) with all subsequent changes detailed on the Mapping Mountains site, with the list also having commenced publication on Mapping Mountains on the 30.01.17.

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:











Myrddyn Phillips and Aled Williams (June 2017)



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