Mapping Mountains – Summit Relocations – 100m Twmpau and Y Trechol – The Dominant Hills of Wales

Cae Uchaf (SS 575 943)

There has been a Summit Relocation to a hill that is listed in the 100m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, drop and status of the hill being confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR summit image of Cae Uchaf

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height with 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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.

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those addition Welsh P30 hills whose prominence is 33.33% or more and below 50% of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

The name of the bounded land where the summit of this hill is situated is Cae Uchaf and this was derived from the Tithe map, and it is the name that this hill is now listed by.  The hill is adjoined to the Gŵyr group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C1), and it is positioned with the B 4296 road to its east, and has the small community of Y Crwys (Three Crosses) at its base to the west south-west.

 

If wanting to visit the hill permission to do so should be sought as the summit area is not a part of designated open access land, for those wishing to do so the nearest public footpath is to the north of the summit.

Prior to LIDAR analysis this hill was listed with 70m of drop and 48.61% dominance based on the 144m summit spot height and 74m bwlch spot height that appear on the Ordnance Survey 1:25,000 Explorer map.

LIDAR bwlch image of Cae Uchaf showing the natural bwlch to be intact

The summit height produced by 1m DTM LIDAR analysis is 144.4m at SS 57511 94397 and its position in relation to that previously given comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, 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, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.

The summit height produced by 1m DTM LIDAR analysis is 144.4m and is positioned at SS 57511 94397, this position is not given a spot height on contemporary Ordnance Survey maps and is approximately 65 metres west and in a different field from where the 144m spot height appears on the Ordnance Survey 1:25,000 Explorer map.   

Ordnance Survey Interactive Coverage Map hosted on the Geograph website showing the summit position in relation to where the 144m spot height appears

  

The full details for the hill are:

Group:  Gŵyr

Name:  Cae Uchaf

OS 1:50,000 map:  159

Summit Height:  144.4m (LIDAR)

Summit Grid Reference (new position):  SS 57511 94397 (LIDAR)

Bwlch Height:  73.4m (LIDAR, natural bwlch remains)

Bwlch Grid Reference:  SS 50983 90868 (LIDAR) 

Drop:  71.0m (LIDAR)

Dominance:  49.19% (LIDAR)

Myrddyn Phillips (November 2018)