Friday, 29 July 2016

Mapping Mountains – Hill Reclassifications – Y Pedwarau

Penmaen Mawr (SH 698 755) - 390m Double Sub-Pedwar addition

There has been an addition to the 390m Double Sub-Pedwar category due to a survey with the Trimble GeoXH 6000.  The hill was not classified prior to the survey with the Trimble, but at one stage in its illustrious career the hill met both Hump and Pedwar criteria as it was given a 1,550ft (472m) map height on the Ordnance Survey Popular and New Popular One-Inch maps, with this height also appearing on the Ordnance Survey Six-Inch map published in 1888.

The hill no longer meets the qualification for these listings as its summit has been quarried and current Ordnance Survey maps only give it an uppermost 370m contour line.  However, quarried areas are usually given no contour lines on Ordnance Survey maps indicating that the ground is or has been in flux, and photographic and map study by Aled indicated that the remaining high point was substantially higher than 370m.

The 390m Double Sub-Pedwarau are the hills at or above 390m and below 400m in height with a drop between 20m and below 30m, with the 390m Sub-Pedwarau being the hills within the same height band and with a minimum 30m of drop.

The hill is situated in the northern part of the Carneddau, and has the towns of Llanfairfechan to its west and Penmaenmawr to its east, with the latter taking its name from the hill.

The name of the hill is Penmaen Mawr and it can be easily accessed from a minor road to the south of the summit that reaches over 260m in height, a public footpath heads north from just below the high point of this minor road and joins a bridlewayed track that contours around the southern slopes of the upper section of the hill.  A large section of the land above the bridleway is open access and the summit of Penmaen Mawr is close to this.

Therefore, Penmaen Mawr is the first hill to be reclassified to the listing of 390m Double Sub-Pedwar hills due to a survey with the Trimble GeoXH 6000 and the list of the Y Pedwarau will be updated accordingly.  The list of Pedwar hills is available from the Haroldstreet (January 2014) website and amendments to the list since this publication have been subsequently reported on the Mapping Mountains site.

The full details for the hill are:

Cardinal Hill:  Carnedd Llywelyn

Summit Height:  390.4m (converted to OSGM15)

Name:  Penmaen Mawr

OS 1:50,000 map:  115

Summit Grid Reference:  SH 69865 75523 
Drop:  26.9m (converted to OSGM15)

Penmaen Mawr (SH 698 755) now confirmed as a 390m Double Sub-Pedwar

Myrddyn Phillips and Aled Williams (July 2016)

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