Mapping Mountains – Summit Relocations – 200m Twmpau

Cae Tŷ Coch (SO 095 413) 

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 Tŷ Coch (SO 095 413)

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 Tŷ Coch 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 a minor road to its west and south-east, and the A470 road to its north-east, and has the small community of Erwyd (Erwood) towards the north.

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub 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 20m of drop, based on the 282m summit spot height positioned at SO 09453 41286 that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated c 262m bwlch height, based on interpolation of 10m contouring between 260m – 270m. 

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 Tŷ Coch (SO 095 413)

LIDAR analysis gives the highest ground on this hill as 282.7m positioned at SO 09549 41332, 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 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 282.7m and this is positioned at SO 09549 41332, this position is not given a spot height on contemporary Ordnance Survey maps and is approximately 96 metres north-eastward from where the spot height appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and importantly placed in a different field. 

 

The full details for the hill are: 

Group:  Mynydd Epynt 

Name:  Cae Tŷ Coch 

OS 1:50,000 map:  161

Summit Height:  282.7m (LIDAR) 

Summit Grid Reference (New Position):  SO 09549 41332 (LIDAR) 

Bwlch Height:  260.65m (LIDAR) 

Bwlch Grid Reference:  SO 09124 41273 (LIDAR) 

Drop:  22.0m (LIDAR) 

 

Myrddyn Phillips (September 2024)