Friday, 9 October 2015

Mapping Mountains – Trimble Surveys – Mynydd Preseli


12.09.15  Foel Cwmcerwyn (SN 094 311) and Foel Eryr (SN 065 320)  

Foel Cwmcerwyn (SN 094 311)

The hills of Foel Cwmcerwyn and Foel Eryr are best combined on a ridge traverse, but having just one car at my disposal I’d decided on a there and back for each hill from the convenience of the car park at the top of the B4329 which bisects one from another as it speeds its way north toward Aberteifi (Cardigan).

As I headed out from the car park it was already attracting a number of cars, with a few walkers heading up the Pedwar of Foel Eryr which would be my last hill of the afternoon before the planned Ynys Aberteifi (Cardigan Island) trip this evening.

The route from the high car park follows the edge of a conifer plantation which smothers the western side of Foel Cwmcerwyn.  Today this path was awash in mud and puddles as the heavy overnight rain had taken its toll.  I’d visited this hill once before and had wanted to re-visit for a number of years as one of my goals is a second round of the Welsh Deweys, with my total still ever creeping upward but it seems to have been slumbering for a number of years, partly due to the Trimbling that is now taking priority.

Foel Eryr from the ascent of Foel Cwmcerwyn

The slosh laden path leaves the forest edge and heads straight over the moor taking a direct route toward the upper fence where a right, southward turn, takes you to the summit of the hill.  It was in this slosh laden wetness that I met two walkers heading in the opposite direction, we stopped and chatted, they were full of smiles even though their trainers and feet were absolutely wet through, these were the same couple of walkers that I’d spotted when on the summit of Carn Siân earlier in the morning.  They were on a 20 mile hike across the summits and ending in Abergwaun (Fishguard).  As they sloshed off toward the coast I continued back toward the path thinking that wellies are a marvellous invention.

The view east from the edge of the forest

As I rounded the forest edge and headed southward the sun cast down upon the lower slopes with the summit in shadow, giving depth and contrast to the view.  Ahead the summit trig pillar quickly gained prominence until I popped out on top, I placed the Trimble on the top of the trig and switched it on and stood back waiting for it to log into the satellite almanac, as I looked down the southern slopes I saw two people approaching with one waving at me, I waved back and recognised the friendly face of John Mackay, the last time we had seen one another was earlier in the year on Ynys Enlli (Bardsey Island), following John was George Morl, who I’d last seen on the Ynys Tudwal Fach and Fawr trip.

The shadowed summit slopes of Foel Cwmcerwyn

It was good to see John and George and once we’d said our hello’s and had our welcoming hand-shakes they explained that Alan Holmes was waiting in his car and that he’d recommended this southern route as the approach to the summit.  It wasn’t surprising to bump into John and George as I wondered if I’d see other baggers on the hills today as with 12 booked on the island trip later in the afternoon they would be off on all manner of P30 hills during the day.

George and John just below the summit of Foel Cwmcerwyn

As the Trimble gathered its data we stood and chatted and then they were gone, and so was I once the customary five minutes of data were gathered and the equipment packed away.  Down I went, back through the slosh to the high car park and over the road to the connecting bwlch with Foel Eryr, listed as a 64m drop Pedwar with a 468m map heighted summit.

Gathering data at the summit of Foel Cwmcerwyn

The critical bwlch was relatively easy to pinpoint and I placed the Trimble down on the ground on the driest patch of moor that I could find.  As it beeped its way to its 300 points of gathered data I stood back and admired the continuation of the path up the north-eastern flank of Foel Eryr.  This hill has a distinctive conically shaped profile and proved a popular ascent as a number of people were heading up it as I had left my car to visit Foel Cwmcerwyn, another couple were descending from the summit as the Trimble was packed away and later on my descent I met a small group of people heading up.

Foel Eryr from its puddle laden bwlch

Once past the puddles at the bwlch I slowly made my way to the summit and chose an embedded rock close to the hill’s panoramic viewfinder for the first of what proved to be three summit data points.

The second point surveyed was on the top of what I judged to be the highest embedded rock at the base of the large and ancient summit cairn that sprawls its way across the summit area of the hill.

Before taking these two data sets I had clambered up the cairn and noticed that there was solid ground and patches of grass about ¾ of the way up it, this of course could just be a part of the ancient cairn with the solid ground constituting the settlement of individual rocks over the millennia that it has stood on the hill.  But I thought I’d get a third data set from this point and placed the Trimble on top of my rucksack to give it a semblance of elevation above the remainder of the cairn.

The third data set at the summit was taken on solid ground approximately ¾ of the way up the cairn

As I left the summit I looked back and wondered if I would ever visit again, this is doubtful but I’ve learnt that one should never say never, as life has a funny twist to it sometimes.  Once back at the car I sorted my gear out and headed toward our planned meeting spot for our visit to Ynys Aberteifi (Cardigan Island).


Survey Result:


Foel Cwmcerwyn

Summit Height:  536.5m (converted to OSGM15)

Summit Grid Reference:  SN 09407 31158

Bwlch Height:  c 191m (interpolation)

Bwlch Grid Reference:  SN 25455 31770 (interpolation)

Drop:  c 346m (Trimble GeoXH 6000 summit and interpolated bwlch)

Dominance:  64.40% (Trimble GeoXH 6000 summit and interpolated bwlch)






Summit Height:  467.4m (converted to OSGM15)

Summit Grid Reference:  SN 06586 32079

Bwlch Height:  403.8m (converted to OSGM15)

Bwlch Grid Reference:  SN 07406 32185

Drop:  63.6m

Dominance:  13.60%




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




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