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

Banc (SN 723 729) – Sub-Trichant reclassified to Trichant

There has been 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 initially confirmed by Joe Nuttall who produced a summit analysis programme using LIDAR, and then by LIDAR analysis initially conducted by Jim Bloomer and subsequently by Myrddyn Phillips.

LIDAR image of 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 13th May 2017.

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

The name the hill is now 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 western part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned with minor roads to its north and south and has the B4340 road to its west and the B4343 road 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 were 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 accompanying main P30 list.

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 a c 286m bwlch height, with the latter based on interpolation of 10m contouring between 280m – 290m that appear on the Ordnance Survey 1:25,000 Explorer map.

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

The details for this hill were later re-assessed and the interpolated bwlch height amended to c 287m, and when coupled with this hill’s 316m summit height these values gave this hill an estimated c 29m of drop.

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.

Therefore, the reclassification of this hill from Sub-Trichant status is due to LIDAR analysis, resulting in a 316.0m summit height and a 285.1m bwlch height, with these values giving this hill 30.9m 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:  316.0m (LIDAR)

Summit Grid Reference:  SN 72380 72986 (LIDAR)

Bwlch Height:  285.1m (LIDAR)

Bwlch Grid Reference:  SN 72097 73104 (LIDAR)

Drop:  30.9m (LIDAR)

Myrddyn Phillips (November 2020)