Mapping Mountains – Hill Reclassifications – Y Trichant – The 300m Hills of Wales

Gallt y Goedhwch (SJ 137 159) – Sub-Trichant reclassified to Trichant

There has been confirmation of a reclassification to the list of Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips with assistance from Mark Trengove and LIDAR analysis conducted by Myrddyn Phillips. 

Gallt y Goedhwch (SJ 137 159)

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

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Gallt y Goedhwch, and it is adjoined to the Foel Cedig group of hills, which are situated in the southern part of North Wales (Region A, Sub-Region A3), and it is positioned encircled by minor roads, with the A490 road farther to its north-east, the B4393 road farther to its north-west, the B4382 road farther to its west and the A495 road farther to its south-east, and has the village of Meifod towards the south-east.

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included as the non-prioritised summit in the Hills to be surveyed sub list that accompanied the main P30 list with an accompanying note stating; Two points of same height (Maes-y-castell SJ137155).  The hill previously listed as Maes-y-castell has now been renamed as Lower Field, and it was this hill that was listed as the prioritised qualifying P30. 

Extract from the Ordnance Survey 1:25,000 Explorer map

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with 114m of drop, based on the 325m summit spot height and the 211m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.

However, it was not until the survey with the Trimble GeoXH 6000 that the details for the summit of this hill could be accurately re-assessed.  The hill has also now been analysed by LIDAR (Light Detection & Ranging); a technique which produced highly accurate height data that is now freely available for much of England and Wales.

The Trimble GeoXH 6000 gathering data at the summit of Gallt y Goedhwch

 

LIDAR bwlch image of Gallt y Goedhwch

Therefore, the confirmation of the reclassification of this hill from Sub-Trichant status is due to a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis, resulting in a 325.7m summit height and a 212.1m bwlch height, with these values giving this hill 113.6m of drop, which is sufficient for it to be classified as a Trichant. 

 

The full details for the hill are: 

Group:  Foel Cedig 

Name:  Gallt y Goedhwch 

OS 1:50,000 map:  125

Summit Height:  325.7m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SJ 13709 15922 (Trimble GeoXH 6000)                                     

Bwlch Height:  212.1m (LIDAR) 

Bwlch Grid Reference:  SJ 11170 14801 (LIDAR) 

Drop:  113.6m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

 

Myrddyn Phillips (September 2022)