Mapping Mountains – Hill Reclassifications – Y Trechol – The Dominant Hills of Wales

THIS HILL HAS SUBSEQUENTLY BEEN DELETED FROM LESSER DOMINANT STATUS

Mynydd Pencarreg (SN 575 432) – Lesser Dominant addition

There has been an addition to the listing of Y Trechol – The Dominant Hills of Wales due to a combination of LIDAR analysis conducted by Aled Williams and a summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the latter taking place on the 31^st July 2018.

The summit of Mynydd Pencarreg (SN 575 432)

The criteria for the list that this reclassification applies to are:

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those addition Welsh P30 hills whose prominence is 33.33% or more and below 50% of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

Prior to LIDAR analysis and the summit survey with the Trimble GeoXH 6000 this hill was listed with an estimated c 138m of drop based on the 415m summit height given to a triangulation pillar that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated bwlch height of c 277m based on interpolation of bwlch contouring between 270m – 280m on these two maps and partial 5m contouring that appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website, with these values giving this hill 33.25% dominance.

                               

The name of the hill is Mynydd Penycarreg and it is the highest hill in own grouping of hills, which are situated in the central part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned between the B 4337 road to the south-west and the A 482 road towards the north-east, and has the town of Llanbedr Pont Steffan (Lampeter) towards the north.

As the summit of the hill is a part of designated open access land permission to visit does not have to be sought, however this open access land is almost an island without any public footpaths leading to it and with only one recognised access point from a minor road to the south-west of the summit.

The addition of Mynydd Pencarreg to Lesser Dominant status is due to LIDAR analysis conducted by Aled Williams coupled with a Trimble GeoXH 6000 summit survey conducted by Myrddyn Phillips.   The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

The survey with the Trimble produced a summit height of 414.9m (converted to OSGM15), whilst the LIDAR analysis produced a bwlch height of 276.2m, with these values giving this hill 138.7m of drop and 33.43% dominance, which confirms its addition to Lesser Dominant status.

The Trimble GeoXH 6000 gathering data at the summit of Mynydd Pencarreg

The full details for the hill are:

Group:  Mynydd Pencarreg

Name:  Mynydd Pencarreg

OS 1:50,000 map:  146

Summit Grid Reference:  SN 57560 43215

Summit Height:  414.9m (converted to OSGM15)

Bwlch Grid Reference:  SN 60011 44082 (LIDAR)

Drop Summit to Bwlch:  138.7m (Trimble summit and LIDAR bwlch)

Drop Bwlch to ODN:  276.2m (LIDAR)

Dominance:  33.43% (Trimble summit and LIDAR bwlch)

For details on the summit survey of this hill

Myrddyn Phillips (December 2018)