Mapping Mountains – Summit Relocations – The Welsh P15s

 

Cae Cenfas Ucha (SN 751 118) 

There has been a Summit Relocation to a hill that is listed in the The Welsh P15s, 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 0f Cae Cenfas Ucha (SN 751 118)

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

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is listed by is Cae Cenfas Ucha and this was derived from the Tithe map, and it is adjoined to the Mynydd Du group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with a minor road to its west and south, and the A4068 road to its east, and has the community of Y Gurnos towards the south-east. 

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

When the listing that became known as The Welsh P15s was being compiled, this hill was not included as with an uppermost 170m contour and bwlch contouring between 160m – 170m that appear on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, it was judged not to meet the criterion for the main P15 or the accompanying P14 sub list. 

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 analysis gives the highest ground on this hill as 183.2m positioned at SN 75115 11857.  However, this is a part of a raised 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 Cae Cenfas Ucha (SN 751 118)

The height produced by LIDAR analysis to the natural summit of this hill is 182.8m and this is positioned at SN 75108 11870, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to when the high point of the hill is positioned in a different field, to a different feature such as a conifer plantation, within a different map contour, a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit 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 height produced by LIDAR analysis to the natural summit of this hill is 182.8m and this is positioned at SN 75108 11870, 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 13 metres north north-westward from where the high point of the raised field boundary is positioned.

 

The full details for the hill are: 

Group:  Mynydd Du 

Name:  Cae Cenfas Ucha 

OS 1:50,000 map:  160

Summit Height:  182.8m (LIDAR)                                                           

Summit Grid Reference (New Position):  SN 75108 11870 (LIDAR) 

Bwlch Height:  164.5m (LIDAR) 

Bwlch Grid Reference:  SN 75202 12488 (LIDAR) 

Drop:  18.3m (LIDAR) 

 

Myrddyn Phillips (May 2024)