Friday, 14 April 2017

Mapping Mountains – Trimble Surveys – Cefn Digoll

24.03.17  Moel y Golfa (SJ 290 125 summit, only bwlch surveyed)

Moel y Golfa (SJ 290 125) in the background with the Trimble positioned at its critical bwlch

I’d wanted to visit this bwlch for quite some time as it’s relatively near to where I live and conveniently placed beside a main road with access to it through a gate.  As I parked on the side of the adjacent minor lane and donned my wellies a chill in the air and slightly misted grey skies predominated.

The bwlch in question is that for Moel y Golfa, which is the high point of the Breiddin and listed as a Dominant, Marilyn, Hump and Pedwar.  Its summit was one of the first that I’d surveyed with the Trimble in December 2013, and it’s always good to then complete the task of adding accurately surveyed heights to both summit and bwlch for any hill.

Once in the field I followed the hedge line northward for 70 metres before heading east, I’d come prepared with a 10 figure grid reference for a centralised bwlch position based on the valley to valley contours, but before finding this spot I wanted to independently judge where the critical bwlch lay.  I found this point relatively easy and left my rucksack there, and then followed the 10 figure grid reference using the Trimble as a hand-held GPS to where map contours suggest the critical bwlch to be positioned, I then left the Trimble there and walked away to get an overall view of the position of one to the other, as the position of the Trimble was on the upward hill to hill traverse I walked back to it, picked it up and concentrated on the position of my rucksack, I looked at this position from a number of directions and decided that I’d found the bwlch.

As the Trimble gathered data I stood back and hoped that a passing farmer wouldn’t become inquisitive and wonder why a person had seemingly abandoned his rucksack in a field and was standing motionless 50 metres from it whilst scribbling in a notebook.  Thankfully this part of Shropshire remained relatively quiet, and except for the traffic on the adjacent A 458 road nothing much stirred.

The Trimble GeoXH 6000 gathering data at the critical bwlch of Moel y Golfa with the Breiddin in the background

Once the allotted data were collected I closed the Trimble down, packed it away and headed back to my car for the onward journey to Shrewsbury to visit a friend and get Euros for next week’s visit to Lisbon.  By the time I’d done both the sun had broken the morning’s grey sky and pleasant afternoon sunshine meant that my planned survey of the high point of Cefn Digoll and its connecting bwlch looked as if it was going to be a relaxing affair.

Survey Result: 

Moel y Golfa

Bwlch Height:  141.4m (converted to OSGM15)

Bwlch Grid Reference:  SJ 32871 12046

Drop:  261.9m (converted to OSGM15)

Dominance:  64.94% 

No comments: