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

 

Pt. 364.9m (SN 901 346) 

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 locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Pt. 364.9m (SN 901 346)

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. 364.9m) 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 Mynydd Epynt group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned encircled by minor roads, with the A40 road farther to its south, and has the village of Pontsenni (Sennybridge) towards the south 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 with a summit height of 364m, based on the spot height positioned at SN 90147 34587 that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

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

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 364m summit spot height and the 339m 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.

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 analysis gives the highest ground on this hill as 366.1m positioned at SN 90164 34612.  However, this is a part of a raised track/field boundary and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Pt. 364.9m (SN 901 346)

The height produced by LIDAR analysis to the natural summit of this hill is 364.9m positioned at SN 90152 34612, and this position in relation to raised track/field boundary 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 considered 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 364.9m and this is positioned at SN 90152 34612, this is relatively close to where the spot height is positioned and is approximately 12 metres westward from the high point of the raised track/field boundary. 

 

The full details for the hill are:

Group:  Mynydd Epynt 

Name:  Pt. 364.9m 

OS 1:50,000 map:  160

Summit Height:  364.9m (LIDAR)                                                           

Summit Grid Reference (New Position):  SN 90152 34612 (LIDAR)                                        

Bwlch Height:  339.0m (LIDAR) 

Bwlch Grid Reference:  SN 90131 34941 (LIDAR) 

Drop:  25.9m (LIDAR) 

 

Myrddyn Phillips (June 2024)