Tuesday, 18 August 2015

Mapping Mountains – Significant Height Revisions – Y Pedwarau

Craig y Derlwyn (SH 702 259) 

This is the sixth post under the heading of Significant Height Revisions, and the following details are retrospective as the Trimble survey that resulted in this height revision was conducted on 3rd May 2014.

The sixth major height revision initiated from a survey with the Trimble GeoXH 6000 was conducted in the hills of the Rhinogydd, which are situated in the west of North Wales between Abermaw (Barmouth) in the south and Trawsfynydd in the north.

The hill is listed as a Sub-Pedwar and can be accessed from the small community of Ganllwyd to its south-east.  However, even though forest paths and tracks head toward the hill much of the land outside of these is rough and wild.  Don’t let this put you off though, as when this hill is combined with its neighbours of Craig Aberserw and Craig y Ganllwyd they make one of the better outings in the eastern part of the Rhinogydd.

The name of the hill is Craig y Derlwyn and its summit height has been increased from its current Ordnance Survey map height, as prior to the survey with the Trimble GeoXH 6000 the hill was listed with a summit height of c 428m based on it having a relatively large uppermost contour ring of 420m on current Ordnance Survey maps.  Its new summit height is 430.8m which is 2.8m higher than its previously estimated height and 10.8m higher than its uppermost ring contour on current Ordnance Survey maps.

The full details for the hill are:

Cardinal Hill:  Y Llethr

Summit Height (New Height):  430.8m (converted to OSGM15)

Name:  Craig y Derlwyn

OS 1:50,000 map:  124

Summit Grid Reference:  SH 70245 25934
Drop:  25.3m

Gathering data at the summit of Craig y Derlwyn

For details on the survey that significantly revised the summit height of this hill please click {here}

Myrddyn Phillips and Aled Williams (May 2014)

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