Mapping Mountains – Summit Relocations – Y Trichant – The 300m Hills of Wales

Pt. 333.2m (SJ 091 161) 

There has been a Summit Relocation to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their location, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Pt. 333.2m (SJ 091 161)

The criteria for the list that this summit relocation 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 being listed by the point (Pt. 333.2m) notation as an appropriate name for it either through local enquiry and/or historic research has not been found by the author, 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 with minor roads to its north, west and south, the B4393 road farther to its north and the B4382 road farther to its west, and has the town of Llanfyllin towards the north-east.

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed with a summit height of 331m based on the spot height that appears on the Ordnance Survey 1:50,000 Landranger map which is positioned at SJ 091 161. 

Extract from the Ordnance Survey 1:50,000 Landranger map

Since publication of the P30 lists on Geoff Crowder’s v-g.me website there have been a number of Ordnance Survey maps made available online, some of these are historic such as the series of Six-Inch maps on the National Library of Scotland website, whilst others are current and digitally updated such as the old Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and the interactive mapping available on the Magic Maps and WalkLakes websites.

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 maps and for this hill it had two 333m summit spot heights positioned at SJ 09191 16163 and SJ 09211 16296, with the prioritised summit relocated to the latter position.

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 summit image of Pt. 333.2m (SJ 091 161)

The summit height produced by LIDAR analysis is 333.2m and is positioned at SJ 09191 16165, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 333.2m and this is positioned at SJ 09191 16165, this position is not given a spot height on the contemporary Ordnance Survey 1:25,000 Explorer map, and is approximately 130 metres southward from where the previously listed priority summit was given. 

 

The full details for the hill are:

Group:  Foel Cedig 

Name:  Pt. 333.2m 

OS 1:50,000 map:  125

Summit Height:  333.2m (LIDAR)                                                           

Summit Grid Reference (New Position):  SJ 09191 16165 (LIDAR) 

Bwlch Height:  305.3m (LIDAR) 

Bwlch Grid Reference:  SJ 09266 16570 (LIDAR) 

Drop:  27.8m (LIDAR) 

 

Myrddyn Phillips (August 2022)