Mapping Mountains – Trimble Surveys – Pumlumon

20.04.14  Pen y Clun (SN 926 875)

Pen y Clun (SN 926 875)

After venturing back up to Dinas (SN 904 885) and visiting the proper summit I drove east, past Llyn Clywedog and parked on the grass verge at SN 923 875 adjacent to the bwlch of a 382m map heighted summit which is situated on land named as Pen y Clun.  I inspected the area of the bwlch many a year ago with Rob Woodall whilst visiting three hills with him; our conclusion was that the hill has approximately c 31m of drop.

It only took a few minutes to judge the bwlch and having decided on the spot to place the Trimble I set it up and waited for it to attain the 0.1m accuracy before data can be logged.  This only took a minute or so, and when it was doing its stuff I happily peered through the gloom toward Bryn y Fan (SN 931 884) across the intervening valley.

Not far from the car to the bwlch for this hill.

Once five minutes of data had been gathered at the bwlch I packed the Trimble away and walked up to the summit.  The word ‘fort’ or ‘hill camp’ appears on a number of Ordnance Survey maps adjoined to this hill, and as one can imagine it has the remains of an ancient hill fort on the summit area.

The highest point is easily identifiable and within a few minutes the Trimble was on it gathering its customary ten minutes of summit data, when this was happening I took a few photos and admired the bulk of Bryn y Fan as it shot up in to the sky line across the valley.

The Trimble GeoXH 6000 on the summit gathering data

45 minutes after leaving the car I was back at it, studying the map as I wanted to investigate one more potential new P30 before the predicted afternoon’s rain arrived. 

Survey Result:

Pen y Clun (significant name change)

Summit Height:  381.7m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 92639 87499 (Trimble GeoXH 6000)

Bwlch Height:  350.2m (LIDAR)

Bwlch Grid Reference:  SN 92437 87531 (LIDAR)

Drop:  31.5m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  8.26% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For further details please consult the Trimble Survey Spreadsheet