Monday, 6 July 2015

Mapping Mountains – Summit Relocations – Y Pedwarau

Pt. 499.5m (SH 665 310) 

There has been a Summit Relocation to the listing of the Y Pedwarau, these are the Welsh 400m P30 hills, initiated from a survey with the Trimble GeoXH 6000.  The following details are retrospective as the Trimble survey that resulted in this summit relocation was conducted on 21st September 2014.

The survey was conducted in the hills of the Rhinogydd, with the hill situated between Abermaw (Barmouth) to the south-west, Dolgellau to the south-east, Harlech to the west and Trawsfynydd to the north-east.  The hill formed part of an excellent day’s walk in the company of Mark Trengove and Dave Middleton.

The hill remains unnamed on current Ordnance Survey maps and as the authors do not yet know an appropriate name for the hill either from local enquiry or from historical research the point (Pt. 499.5m) notation is being adopted for it.  The hill was previously listed as a 400m Sub-Pedwar and was reclassified to a Pedwar from the same survey that also initiated its summit relocation.

The hill is listed as Pt. 499.5m, when listed as a 400m Sub-Pedwar its summit position was given to where the 499m spot height appears on current Ordnance Survey maps, this position is at SH 66549 31044 and consists of the highest part of the rock perched at the top of a small cliff. 

The position of the relocated summit is at SH 66565 31003 and is the top of a large erratic boulder, this position is not given a spot height on current Ordnance Survey maps but the Trimble GeoXH 6000 result gave it as 0.6m higher than where the spot height appears on the ground.

The full details for the hill are:

Cardinal Hill:  Y Llethr

Summit Height:  499.5m (converted to OSGM15)

Name:  Pt. 499.5m

OS 1:50,000 map:  124

Summit Grid Reference (New Position):  SH 66565 31003 
Drop:  30.3m (converted to OSGM15)

The Trimble GeoXH 6000 gathering data at the new summit position of Pt. 499.5m, with the old position of the summit on the left and just above the centre of this photograph

For details on the survey that relocated the summit of this hill please click {here}

Myrddyn Phillips and Aled Williams (September 2014)

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