Wednesday, 17 October 2018

Mapping Mountains – Trimble Surveys – Mynydd Pencarreg


31.07.18  Mynydd Pencarreg (SN 575 432)

Mynydd Pencarreg (SN 575 432)

As I drove south toward Mynydd Pencarrag, the first hill of a planned twelve over two days and mainly in the vicinity of Caerfyrddin (Carmarthen), the dry roads around the northern part of mid Wales gave way to wet tarmac with muddied puddles beside their edges, there had been heavy overnight rain and the grey skies had not cleared as the further south-west I drove the murk heralded more rain.  I missed my turn off on the B4337 toward Llanybydder and this at least gave the hills another unplanned 30 minutes to clear their tops of drizzled murk.

Access to Mynydd Pencarreg is easy if choosing the end of the minor lane to the south-east of the summit that gives access to the large mast in the adjacent field.  This is a transmitting station which incorporates a 99m (325ft) high mast, and provides digital television and FM radio to the Lampeter area.

By the time I parked my car and tied up my walking boots the skies directly overhead were free of wet murk, but all around looked forbiddingly bleak as heavy dark grey cloud sped in from the west, with the western coastal regions looking decidedly grey with no doubt lots of rain.

I used the access track to the transmitter mast hoping this would lead direct to the high point of the hill, I suspect it does via a gate, but I doubled back to gain access to a field where the trig pillar at the summit was now in view.

It was only a short walk to the trig pillar and the erratic boulder placed a few metres away which is taken as the summit of the hill, this stood out from afar and it soon had the Trimble perched on its high point gathering the allotted data.

Gathering data at the summit of Mynydd Pencarreg

The Trimble set-up position at the summit of Mynydd Pencarreg

When data were being gathered I headed further north-west in to the adjacent field to visit its high point and look back at the trig, boulder and mast, and take photos as dark cloud zoomed overhead interspersed with flashes of sunlight.  Away to the south-west was the next hill I planned to visit; Mynydd Llanybydder and this again was battling with darkened murky cloud interspersed with occasional flashes of sunlight.

The high transmitting mast near the summit of Mynydd Pencarrag

Dark clouds massing as the Trimble gathers data

By the time seven minutes of data were gathered and stored the murk was heading my way, so I quickly packed the Trimble away and left the hill down a field and took a line straight toward my car, as I arrived the first drops of rain were falling and Mynydd Llanybydder was now immersed in wet clag with its forested slopes looking decidedly uninviting.



Survey Result:


Mynydd Pencarreg

Summit Height:  414.9m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 57560 43215 (Trimble GeoXH 6000)

Bwlch Height:  276.7m (LIDAR)

Bwlch Grid Reference:  SN 60000 44090 (LIDAR)

Drop:  138.2m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  33.32% (Trimble GeoXH 6000 summit and LIDAR bwlch) (Lesser Dominant addition) (Lesser Dominant deletion) 











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