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

Coed y Gaer (SO 004 843) – Lesser Dominant addition

There has been an addition to the listing of Y Trechol – The Dominant Hills of Wales prompted by a survey with the Trimble GeoXH 6000 and confirmed by subsequent LIDAR analysis; resulting in this hill being included in the Lesser Dominant sub list.

With the criteria for inclusion to the Dominant list being those Welsh P30 hills whose prominence equal or exceed half that of their absolute height, whilst the criteria for the Lesser Dominant list are those additional Welsh P30s whose prominence is 33% or more and below 50% of their absolute height.

The details relating to the inclusion of this hill in the Lesser Dominant category are retrospective as the confirmation of its addition is dependent upon a survey with the Trimble GeoXH 6000 which was conducted on the 9^th February 2014, with the relevant post giving the survey details appearing on Mapping Mountains on the 11^th February 2014.

When the sub category of hills accompanying the Welsh P30 lists published on Geoff Crowder’s v-g.me website were standardised with interpolated drop values, this hill was listed with an estimated c 119m of drop based on its 362m summit spot height and an estimated bwlch height of c 243m, these values gave this hill 32.87% dominance, which was insufficient for it to be classified as a Lesser Dominant hill.  The drop value was subsequently altered due to a 241m bwlch spot height appearing on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, this resulted in the dominance of the hill also being amended.

The name the hill is listed by is Coed y Gaer and it is adjoined to the Hirddywel group and is placed in the Region of Mid and West Wales (Region B, Sub-Region B1) with its Cardinal Hill being Pegwn Mawr (SO 023 812), and is situated above the A 470 road and the Afon Hafren (River Severn) which are to its north, and it is positioned between the small community of Llandinam to the north north-east and the town of Llanidloes to the west.

As the hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so a minor lane to the south of the hill gives access to steep slopes leading to the summit.

Therefore, the addition of Coed y Gaer to Lesser Dominant status was prompted by a Trimble GeoXH 6000 survey and subsequently confirmed by LIDAR analysis, resulting in a 361.0m summit height and a 239.5m bwlch height, with these values giving this hill 121.5m of drop and 33.65% of dominance.

LIDAR image of Coed y Gaer (SO 004 843)

  

The full details for the hill are:

Group:  Hirddywel

Name:  Coed y Gaer

Dominance:  33.65% (LIDAR)

OS 1:50,000 map:  136

Summit Grid Reference:  SO 00491 84393 (LIDAR)

Summit Height:  361.0m (LIDAR)

Drop Summit to Bwlch:  121.5m (LIDAR)

Drop Bwlch to ODN:  239.5m (LIDAR)

For details on the survey that confirmed the addition of this hill to Lesser Dominant status

Myrddyn Phillips (August 2017)