Mapping Mountains – Summit Relocations – 200m Twmpau

Cae Cwar y Coed (SN 828 343) 

There has been a Summit Relocation to a hill that is listed in the 200m Twmpau, 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 Cae Cwar y Coed (SN 828 343)

The criteria for the list that this summit relocation applies to are:

200m Twmpau - Welsh hills at or above 200m and below 300m in height that have 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 200m and below 300m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

200m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Cae Cwar y Coed and this was derived from the Tithe map, 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 with minor roads to its north-west and east, and the A40 road to its south, and has the town of Llanymddyfri (Llandovery) towards the west.

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a 248m summit height, based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map at SN 82773 34291.  This position was subsequently changed to SN 82761 34285, based on on-site visits and GPS data recorded on the Hill Bagging website. 

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. 

LIDAR summit image of Cae Cwar y Coed (SN 828 343)

LIDAR analysis gives the highest ground on this hill as 246.6m positioned at SN 82809 34336, and this position in relation to the previously listed summit position 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 246.6m and this is positioned at SN 82809 34336, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 50 metres north-eastward from the previously listed summit position and importantly it is also positioned in a different field. 

 

The full details for the hill are: 

Group:  Mynydd Epynt 

Name:  Cae Cwar y Coed 

OS 1:50,000 map:  160

Summit Height:  246.6m (LIDAR) 

Summit Grid Reference (New Position):  SN 82809 34336 (LIDAR) 

Bwlch Height:  215.4m (LIDAR) 

Bwlch Grid Reference:  SN 83737 35272 (LIDAR) 

Drop:  31.2m (LIDAR) 

 

Myrddyn Phillips (March 2024)