Tuesday, 25 August 2015

Mapping Mountains – Significant Height Revisions – Y Pedwarau

Bryn Melyn (SO 109 184)

This is the ninth 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 22nd July 2014.

The ninth major height revision initiated from a survey with the Trimble GeoXH 6000 was conducted in the hills of the Bannau Brycheiniog (Brecon Beacons) in south Wales, in the company of Mark Trengove who had suggested the walk.

The hill appears in the listing of Y Pedwarau and can be easily accessed from the end of a minor road above the waters of the Talybont Reservoir which is situated in Glyn Collwn.  The hill can also be accessed from its opposing valley of Dyffryn Crawnon which gives a slightly more rewarding and lengthy walk.

The name of the hill is Bryn Melyn 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 446m based on it having an uppermost contour ring of 440m on current Ordnance Survey maps.  Its new summit height is 450.5m (converted to OSGM15) which is 4.6m higher than its previously estimated height and 10.5m higher than its uppermost ring contour on current Ordnance Survey maps.

The full details for the hill are:

Cardinal Hill:  Pen y Fan

Summit Height (New Height):  450.5m (converted to OSGM15)

Name:  Bryn Melyn

OS 1:50,000 map:  161

Summit Grid Reference:  SO 10941 18432
Drop:  38.6m

Gathering data from the summit of Bryn Melyn which resulted in this hill's significant height revision

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

Myrddyn Phillips and Aled Williams (July 2014)

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