Saturday, 20 May 2023

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


Pant y Crug (SN 657 458) – 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 derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Pant y Crug (SN 657 458)

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, and the Introduction to the Mapping Mountains publication of the list appearing on the 1st January 2022. 

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

The name the hill is listed by is Pant y Crug and this was derived from the Tithe map, and it is adjoined to the Esgair Wen group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north-west, south and east, and the A482 road farther to its south-west, and has the town of Llanbedr Pont Steffan (Lampeter) towards the west north-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 25m of drop, based on the 334m twin summit spot heights that appear on the Ordnance Survey 1:25,000 Explorer map and the 309m 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. 

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.

Therefore, the reclassification of this hill from Sub-Trichant status is due to LIDAR analysis, resulting in a 334.4m summit height and a 304.3m bwlch height, with these values giving this hill 30.1m of drop, which is sufficient for it to be classified as a Trichant. 

 

The full details for the hill are: 

Group:  Esgair Wen 

Name:  Pant y Crug 

OS 1:50,000 map:  146

Summit Height:  334.4m (LIDAR)                                                           

Summit Grid Reference:  SN 65795 45897 (LIDAR) 

Bwlch Height:  304.3m (LIDAR) 

Bwlch Grid Reference:  SN 66317 46159 (LIDAR) 

Drop:  30.1m (LIDAR) 

 

Myrddyn Phillips (May 2023)

 

 

 

 

 

  

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