Sunday 13 September 2020

Mapping Mountains – Trimble Surveys – Carnedd Wen


06.06.20  Y Golfa (SJ 182 070), previously Trimbled

Y Golfa (SJ 182 070)

When Aled and I stood atop Pen y Cerrig Serth on the 19th January earlier this year I couldn’t foresee this as the last summit I would visit for almost five months.  The intervening time has brought a pandemic, the likes of which has not been seen for over 100 years.

The Coronavirus; Covid-19 has killed over 400,000 people worldwide and over 40,000 of these in Britain, and to combat its spread a lock down was instigated on the 23rd March.  This is slowly being lifted throughout Britain, with firstly England taking the plunge of opening up with the other constituent countries of the UK being more circumspect.

Throughout the last 2½ months I’ve followed instructions and not travelled to take the allotted daily exercise instructed by the Welsh Government.  Therefore any exercise I’ve taken is from my own doorstep and hill walks farther afield must wait until the countryside is once again open.

Although many of the instructions due to the outbreak of Covid-19 are harsh, they are understandable and necessary.  This has obviously limited everyone’s hill walking, or at least those who have abided the instruction, as some unfortunately haven’t.

The outbreak and resulting limited scope for hill walking has reconnected me to my local landscape and enabled late evening walks from my doorstep, mainly using the towpath beside the Montgomeryshire Canal for access to the countryside.  But until this evening I had not visited a summit of a hill.  Over the last 2½ months I’d looked toward a variety of hills from elevated views above Welshpool as the main Berwyn ridge distantly looked back at me, and the Breiddin, Cefn Digoll, Yr Allt, Moel y Garth, Upper Park and Y Golfa all were on grand display.  These hills were always on show as the sunniest spring since records began gave two months of sunshine and increasingly warm temperatures.  However, the weather has now broke and rain has recently set in, with the temperature giving cooler conditions, and although this afternoon gave showers, the forecast for the evening was good.

I’d recently investigated public footpaths connecting the Frochas Lane with the estate grounds of Llanerchydol, and now wanted to use the latter as an ascent route to the summit of Y Golfa, which I had done on two previous occasions, the last of which when I Trimbled its summit in August 2014.

Setting off at 6.55pm the canal towpath gave access to the Back Lane which leads toward the Raven roundabout and the paved road heading west out of the confines of Welshpool, to the quiet pastured old estate grounds of Llanerchydol Hall.  As ever it was good to be out and especially so during an evening, which I rarely do when hill bagging.

The pleasantly warm conditions and cloudless deep blue skies of the last two months had been replaced with bubbled cloud and a cooling evening.  I hoped that I could watch a lowering sun from the summit before scampering off to find a descent route enabling a circular walk before darkness overtook me.

Upper Park on the left and Cromwell Hill on the right

The paved road leading through the old estate grounds gives a tranquil ascent route with grazing sheep and inquisitive cows a plenty.  This soon turns to a vehicle track as it gains height past Home Farm and Pen-y-golfa.  The continuing public footpath then heads across a field and beside the Golfa Wood before leading to a variety of green tracks high on the hill’s eastern flank, each through summered fern and undergrowth.

The Breiddin and Shropshire Plain beyond

Across the valley Upper Park and Cromwell Hill caught the last glimmers of sunlight, whilst farther to the east the Breiddin rose above the Shropshire Plain.  Appearing ahead of me the white trig pillar stood bolt upright signifying the high point of the hill.  I had hoped that low light would cast illuminated colour on the trig giving me opportunity for a number of photos framing it in the foreground with distant views beyond.  As I approached the sun sank behind a cloud bank out to the west leaving dulled colour on the hill.  I had missed my opportunity by no more than a couple of minutes; however I could not linger as it was now 9.00pm and I had to devise a descent route.

The summit of Y Golfa
Below me the Gaer Farm looked an inviting way to connect with the Frochas Lane, so off I scampered on more earthen tracks and narrower footpaths, past manicured golfing greens and eventually down a field to a track, past friendly horses and a relatively recent new paved road heading uphill to The Gaer.  From here I could, if I wanted, remain on a paved road all the way toward Welshpool.  However, I had a number of options available to connect with my home town, and one involved using the public footpath I’d recently been on that heads across fields to Lower Llanerchydol, this would also give me the shortest and quickest route back.

It was 10.00pm as I scampered across the fields toward Lower Llanerchydol.  The sun had sunk, leaving delicate mauved clouds peering across the sky.  The paved road through the old estate took me down to the Raven roundabout and the Back Road through Welshpool and finally the canal towpath where I was accompanied by dancing bats on my way back home.  Arriving at my front door I looked at my watch, it was 10.40pm; it was time for a large mug of tea and a contented sleep.

LIDAR image for the bwlch of Y Gofa

The following day I checked the Trimble result for the summit and examined the area of this hill’s bwlch via Google Maps before downloading LIDAR to see if the bwlch was covered.  It was, just.  I then spent an inordinate amount of time building up LIDAR contouring and comparing this to the digitised image on my laptop via the Google car.


The bwlch of Y Golfa, with the critical point just through the gate on the left, and across the field toward the fence.  Photo:  Google Maps

The contrast between a hill walk to a summit where data is then gathered and stored in the Trimble GeoXH 6000 and producing the same via LIDAR on a laptop is extreme.  One gives beauty and the other involves staring at a screen whilst tapping endlessly on a keypad.  However, the end result is accurate numerical data and this is presented below.



Survey Result:


Y Golfa

Summit Height:  341.4m (from previous Trimble GeoXH 6000 survey) 

Summit Grid Reference:  SJ 18247 07086 (from previous Trimble GeoXH 6000 survey) 

Bwlch Height:  175.1m (LIDAR)

Bwlch Grid Reference:  SJ 16645 06017 (LIDAR)

Drop:  166.3m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  48.72% (Trimble GeoXH 6000 summit and LIDAR bwlch)







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