Tuesday, 10 December 2019

Mapping Mountains – Trimble Surveys – Y Berwyn

13.09.19  Craig Berwyn (SJ 071 323), only bwlch surveyed

It felt good to be standing in a bog.  I hadn’t done this for a number of weeks and the heather bound morass where the bog was situated was a delight with the first purples of bloom and vivid late afternoon greens picked out by a lowering sun.  Not surprisingly I had the bog all to myself, although the road passing over the Y Berwyn was no more than a couple of minutes’ walk away.  I wondered why more people weren’t stopping to savour the bog’s delight.  They didn’t know what they were missing.

The summit of Craig Berwyn (SJ 071 323)

I wonder if Bog Bwlch Surveying has ever trended on the Internet, if it hasn’t it should as it has a surreal appeal all to its self.  This particular bog is connected to the highest point of the Y Berwyn; Craig Berwyn and if not for the near road it would be a quiet spot, however its water laden depths must surely be seldom visited other by a rogue sheep or scampering fox.

I’d come prepared with a ten figure grid reference initially produced by Aled Williams from LIDAR analysis, and afterward also by myself.  LIDAR only has partial coverage for the area of this bwlch, but what is covered is sufficient to produce a grid reference within a metre or two of its critical point.

LIDAR bwlch image for Craig Berwyn

LIDAR close up bwlch image for Craig Berwyn

This was the last of six such roadside surveys during the day and all under a succulent blue sky and sunshine to savour.  As I left my car I walked over the road and immersed myself in heather, this can be rather comforting if soft and especially so if the experience is not protracted.  Today was one such occasion, with just a few minutes spent in the bog laden heather bound morass, just enough to enjoy and not too much to detract.

Considering the amount of heathered surrounds it would not be too difficult a task to pinpoint the bwlch without the aid of LIDAR, but having the all-important ten figure grid reference led to the critical point and within a few minutes the Trimble was set-up gathering data. 

Gathering data at the bwlch of Craig Berwyn

During data collection I tried in vain to find a dry patch of ground to stand on, to be fair the bog was not too bad compared to some whose delights I’ve experienced, but it was never the less a watery haven.

Once the allotted data were gathered and stored I closed the equipment down, packed it away and looked out across the heather to distant hills and a blued horizon, what a stunning place.

Survey Result:

Summit Height:  832.0m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)

Summit Grid Reference:  SJ 07163 32351

Bwlch Height:  484.7m (converted to OSGM15)

Bwlch Grid Reference:  SJ 01628 30532

Drop:  347.3m

Dominance:  41.74%


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