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

 

Banc (SN 723 729) – 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 LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips. 

Banc (SN 723 729)

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. 

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

The name the hill is listed by is Banc and this was derived from the Tithe map, and it is adjoined to the Elenydd group of hills, which are situated in the central part of the Mid and West Wales Region (Region B, Sub-Region B2), and is positioned with minor roads to its north-east, north-west and south, and has the B4343 road farther to its east, and has the village of Pont-rhyd-y-groes towards the east south-east. 

When the original 300m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for the main P30 category. 

When 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 an estimated c 30m of drop, based on the 316m summit spot height and an estimated c 286m bwlch height based on interpolation of 10m contouring between 280m – 290m that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR image of Banc (SN 723 729)

LIDAR analysis confirms Banc to have over 30m of drop and as the summit of this hill has now been surveyed with the Trimble GeoXH 6000 it is this result that is being prioritised for listing purposes. 

The Trimble GeoXH 6000 gathering data at the summit of Banc

Therefore, the confirmation of the reclassification of this hill from Sub-Trichant status is due to LIDAR analysis and a subsequent Trimble GeoXH 6000 survey, resulting in a 316.3m summit height and a 285.1m bwlch height, with these values giving this hill 31.2m of drop, which is sufficient for it to be classified as a Trichant. 

 

The full details for the hill are: 

Group:  Elenydd 

Name:  Banc 

OS 1:50,000 map:  135, 147

Summit Height:  316.3m (converted to OSGM15, Trimble GeoXH 6000)                                                           

Summit Grid Reference:  SN 72380 72987 (Trimble GeoXH 6000) 

Bwlch Height:  285.1m (LIDAR) 

Bwlch Grid Reference:  SN 72097 73104 (LIDAR) 

Drop:  31.2m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

 

Myrddyn Phillips (September 2021)