Saturday, 29 August 2015

Mapping Mountains – Significant Height Revisions – 200m Twmpau

Pen y Berth (SJ 081 127)  

This is the eleventh 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 19th October 2014.

The eleventh major height revision initiated from a survey with the Trimble GeoXH 6000 was conducted in the lower Berwyn hills in the company of Mark Trengove on a colourful autumnal day in October.

The hill can be accessed from 1km east of the small community of Dolanog on a track that heads north-west and then east to sneak up to the summit from the opposing side of the hill.  The summit area of the hill is given two 280m uppermost ring contours aligned east and west of one another on Ordnance Survey maps, with each contour ring given a 282m spot height that appears on the Ordnance Survey enlarged map on the Geograph website.

The name of the hill is Pen y Berth and the following results were those obtained with the Trimble GeoXH 6000 for the two points surveyed:

Eastern 282m spot height:  283.7m (converted to OSGM15) at SJ 08322 12748

Western 282m spot height at SJ 08012 12780 not surveyed

Easterly high point of western 280m ring contour:  287.5m (converted to OSGM15) at SJ 08126 12730

The land at SJ 08126 12730 was visually judged to be higher than the land at SJ 08012 12780, therefore this latter position was not surveyed.  The height given the hill on current Ordnance Survey maps is 282m, with the height resulting from the survey with the Trimble being 287.5m.

Therefore this hill’s new summit height is 5.5m higher than its previously listed height which came from the 282m spot height on the Ordnance Survey enlarged map on the Geograph website.

The full details for the hill are:

Cardinal Hill:  Carreg y Big

Summit Height (New Height):  287.5m (converted to OSGM15)

Name:  Pen y Berth

OS 1:50,000 map:  125

Summit Grid Reference:  SJ 08126 12730 
Drop:  134.2m

Pen y Berth (SJ 081 127) - a hill that's had it's height significantly revised

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

Myrddyn Phillips (October 2014)

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