Friday, 13 November 2015

Mapping Mountains – Hill Reclassifications – 100m Twmpau


The Pimple (SJ 299 472)

There has been a new addition to the Sub category within the 100m Twmpau (thirty welsh metre prominences and upward) hill list instigated by a survey with the Trimble.   The hill is situated next to the small community of Pentre Bychan which is adjacent to Rhosllanerchrugog, in the easterly part of the Bryniau Clwyd.

These details are retrospective as the Trimble GeoXH 6000 survey that resulted in this hill’s inclusion as a 100m Sub- Twmpau was conducted on the 20th October 2015 on a beautiful autumnal day in good, dry and sunny conditions.

The hill can be accessed from its west where a public footpath traverses the course of the valley where its bwlch is positioned.  However, permission should be sought for those wishing to visit as the summit is not on open access land.  When I visited I asked permission to do so and was kindly directed to the best ascent route.

The hill is named The Pimple and its summit is positioned at SJ 299 472.  This is a locally known name for the hill and was found when I made enquiries during a number of data sets taken at the area of the bwlch.  The hill remains unnamed on current Ordnance Survey maps and its locally known name relates directly to the past industrial heritage of the hill, as its summit is made of mining waste that is now stabilised and grassed over.  The uppermost part of the summit is relatively small in area and squat, and looks like a pimple as it sits upon another elevated part of the hill.

Current mapping does not give this hill any summit ring contours, although the adjacent field does have a 154m map spot height on it, both of these points were surveyed with the summit known as The Pimple being 0.4m higher according to the Trimble data.

The survey with the Trimble GeoXH 6000 resulted in a 153.5m (converted to OSGM15) summit height and a 128.3m (converted to OSGM15) bwlch height, giving this hill 25.2m of drop and confirming its entry in to the 100m Sub-Twmpau ranks.


The full details for the hill are:

Cardinal Hill:  Moel y Gamelin

Summit Height:  153.5m (converted to OSGM15)

Name:  The Pimple

OS 1:50,000 map:  117

Summit Grid Reference:  SJ 29984 47262

Drop:  25.2m


Gathering data at the summit of The Pimple, which resulted in this hill's confirmation as a 100m Sub-Twmpau

For details on the survey that resulted in this hill being included as a 100m Sub-Twmpau please click {here}


Myrddyn Phillips (October 2015)

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