Saturday 20 September 2014

Mapping Mountains – Trimble Surveys – Mynydd Hiraethog


19.09.14  Foel Greon (SH 977 635)

Foel Greon (SH 977 635).  Photo:  Mark Trengove, taken on a sunnier day

The monochrome stillness when summer haze predominates can sometimes give an unusual tranquillity, partly enhanced by lack of highlighted colour as the land is washed and devoid of that magical colour element.  Because of this one’s attention seems to close in to ground close at hand, this can be comforting as periphery detail of view and colour is supplanted by the immediacy of thought and motion.  I usually try and avoid days when murk from southerly climes pushes the northern freshness away, they are sometimes rather non-descript in ambiance, but unusually they are also serene in nature. 

But these grey and overcast days can be good to meet hill walking friends for an evening wander when the country is quiet and the land relaxes in to its night time vigil.  This evening’s little wander was to a P30 that Mark and I had yet to visit, it’s always good to visit new ground, even if the land is smothered in greyness and murk.

The hill Mark had suggested visiting was Foel Greon, which is part of the Mynydd Hiraethog and can be easily visited from the small community of Bylchau, which is a few miles westward of Dinbych (Denbigh).  The hill’s map height is 398m and therefore it is only 2m under the minimum qualifying height for Pedwar status, and it was this that interested us.

We met in Morrisons café in Dinbych and scoffed our faces full of unsavoury stuff and then drove the short distance to the start of our walk.  We headed up the hill on a public footpath that soon headed toward small foot stiles straddling the many barbed wire fences on the hill side.

Mark heading up the hill

To the west the sun sank in a milkened sky and a flock of birds flew their way to unknown realms.  Ahead lay an array of inquisitive sheep, all a line and watchful, only disappearing as we continued toward them.

Birds in flight

Rob Woodall had reported on Hill Bagging that there are two possible mounds for summit position and when we arrived on the high point these are easily recognised.  The one to the north looked slightly higher.  As the evening turned to night the Trimble was positioned on the high point of each and gathered five minutes of data from each position.

The first point surveyed on the area of the summit was at SH 97736 63541 and came to 398.11m


The second point surveyed on the area of the summit was at SH 97701 63544 and came to 398.00m

We then reversed our route and investigated the area of the bwlch, first by walking up and down the road that skirts the few houses in Bylchau, when assessing the bwlch by eye one possibility for the position of the critical bwlch was next to the road on a triangle of grass where the A543 intersects with the A544.  However, we used a ten figure grid reference for the 329m map spot height that appears adjacent to the main road and pinpointed where this was on the ground.  It was on a slight rise of grass bank and probably just in someone’s garden, it was also not at the critical bwlch as this seemed to be a few metres away on the narrow road that the spot height appears on.

Bad habits die hard - surveying next to a road at the critical bwlch of Foel Greon

Once the position was chosen the Trimble was set up and gathered its five minutes of data, the point chosen was no more than a narrow road width away from where I had parked my car.  I did think about moving it to give the Trimble better satellite reception but it gained its 0.1m accuracy before data can be logged remarkably quickly considering the proximity of cars, houses and high trees.  A few minutes later and we were heading back to Morrisons car park to pick up Mark’s car.  Another enjoyable evening’s wander


Survey Result:


Foel Greon

Summit Height:  398.1m  (converted to OSGM15) 
 
Summit Grid Reference:  SH 97736 63541

Bwlch Height:  329.6m (converted to OSGM15)

Bwlch Grid Reference:  SH 97552 63009

Drop:  68.6m 

Dominance:  17.22%


 

For further details please consult the Trimble survey spreadsheet click {here}


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