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

Pt. 303.45m (SH 874 163) – 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 conducted by Myrddyn Phillips. 

LIDAR image of Pt. 303.45m (SH 874 163)

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 hill is listed by the Point (Pt. 303.45m) notation as an appropriate name for it either from historic research or local enquiry has not been found, and it is adjoined to the Aran Fawddwy group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and it is positioned with minor roads to its west and south, and the A470 road farther to its south-west, and has the small town of Dinas Mawddwy towards the south-west. 

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 main P30 category. 

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 an estimated c 27m of drop, based on the 304m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 277m bwlch height, based on interpolation of 10m contouring between 270m – 280m. 

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

The details for this hill were re-assessed against Harvey Map data using the 1:40,000 Snowdonia South British Mountain Map.  This mapping has many spot heights not on other publicly available maps and for this hill is has a 304m summit spot height and a 269m bwlch spot height, with these values giving this hill 35m of drop. 

Extract from the Harvey 1:40,000 Snowdonia South British Mountain Map

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on other publicly available Ordnance Survey maps and for this hill it had a 272m bwlch spot height which was prioritised over the Harvey Map data, and when coupled with the 304m summit spot height, these values give this hill 32m 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 confirmation of the reclassification of this hill from Sub-Trichant status is due to LIDAR analysis, resulting in a 303.45m summit height and a 271.1m bwlch height, with these values giving this hill 32.4m of drop, which is sufficient for it to be classified as a Trichant. 

 

The full details for the hill are: 

Group:  Aran Fawddwy 

Name:  Pt. 303.45m 

OS 1:50,000 map:  124, 125

Summit Height:  303.45m (LIDAR)                                                           

Summit Grid Reference:  SH 87457 16343 (LIDAR) 

Bwlch Height:  271.1m (LIDAR) 

Bwlch Grid Reference:  SH 87614 16397 (LIDAR) 

Drop:  32.4m (LIDAR) 

 

Myrddyn Phillips (January 2022)