Mapping Mountains – Trimble Surveys – Moelwyn Mawr

 

22.09.21  Garth Ganol (SH 626 394) 

LIDAR image of Garth Ganol (SH 626 394)

Garth Ganol was the last of three hills we visited during the day.  Each were wooded, with the first; Bryn y Gwynt (SH 599 499) and this last hill being relatively easy walks compared to the brambled domain of the second hill; Cefn Coch (SH 610 396). 

These three hills proved an ideal way to salvage the day as the weather in the morning was particularly unwelcome, with low cloud and wet conditions in this part of Wales, which meant that our planned outing to Moel y Dyniewyd (SH 612 477) and it adjacent hills was shelved for a more favourable day. 

Garth Ganol forms a part of a small peninsula overlooking the Afon Dwyryd close to where it deposits its contents in to the sea.  Aled had previously approached this hill from the south-west and visited an intermediary top.  This approach was recommended but it would also give us a longer route through probable unsavoury undergrowth.  Therefore, we opted for the easy approach and drove up an unmarked paved road to just below the summit to its north. 

Before starting up the hill I asked permission at a house beside the road named Bryn Dwyryd, whether we could park the car beside a large barn a 100 or so metres from the house, with permission granted we eventually opted to park close to a gate which was off the paved section of road. 

Heading up through the wooded northerly slopes of the hill

The gate gave access in to woodland that forms a large part of this hill.  Above us were bee hives which we not surprisingly purposely avoided.  Once through the first gate, a dirt track led to another solid gate and from here I followed Aled as he weaved a way upward through the mature woodland to emerge out of the trees near the summit of the hill. 

Bracken, gorse and heather and the added bonus of a barb wired fence

We were now standing on a small intermediary top with the summit of the hill on the other side of a barb wired fence, between us and it was a good scattering of gorse.  Although prickly if wearing shorts; as I was, gorse is not problematic unless thick and high.  Thankfully the gorse we encountered on this hill was neither and we were soon on what looked to be the summit.  However, ground to our south-west needed investigating and I again followed Aled as he headed that way.  Once there we deemed it higher. 

Gathering data at the summit area of Garth Ganol

There were a number of points that vied for summit position, all a few metres apart and all of similar height, we chose the one we thought the highest and soon the Trimble was set up gathering data.  When back home I analysed this hill with LIDAR and this gives the Trimble set-up position approximately eight metres from the summit and as the height produced by LIDAR is 0.25m higher than the height produced by the Trimble GeoXH 6000 survey, it is the LIDAR data that is being used for listing purposes.  In our defence the summit identified by LIDAR looks to be positioned in a large outcrop of heather and gorse, with the natural ground below being extremely hard to distinguish in height compared to its near surrounds. 

Looking out toward the rough surrounds of the northern Rhinogydd and the Afon Dwyryd

We of course, were oblivious to the LIDAR summit position, but it is always good to get a comparison against data produced by the Trimble GeoXH 6000.  During data collection I stood and admired the view south-eastward across to the rough slopes forming a part of the northern Rhinogydd and eastward down the near estuary of the Afon Dwyryd.  It felt good to be on an open summit after the confines of the two previously visited wooded hills. 

Heading down with the higher cloud enshrouded Moelwynion in the background

Once data were gathered and stored we reversed our inward route, back to and then over the barb wired fence and down through the wood to the awaiting car.  It had been another excellent day with three hills visited, in good company with good conversation, a meal sitting outside a café in Llanfrothen, and a panad or two along the way! 

 

Survey Result: 

 

Garth Ganol (significant name change)

Summit Height:  75.6m (LIDAR)

Summit Grid Reference:  SH 62600 39430 (LIDAR)

Bwlch Height:  27.7m (LIDAR)

Bwlch Grid Reference:  SH 62671 40069 (LIDAR)

Drop:  47.8m (LIDAR)

Dominance:  63.30% (LIDAR)

 

 

For further details please consult the Trimble Survey Spreadsheet