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

Pen Aran Hill (SO 137 888) 

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 and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips. 

Pen Aran Hill (SO 137 888)

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. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Pen Aran Hill and this was derived from local enquiry, and it is adjoined to the Cilfaesty group of hills, which are situated in Mid and West Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north-west and south-east and the A489 road to its north-east, and has the village of Ceri (Kerry) towards the north-east.

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

When the original 300m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was listed under the name of Penarron with a 368m summit height, based on the spot height that appears on the Ordnance Survey 1:50,000 Landranger map and which is positioned at SO 13837 89083. 

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 Pen Aran Hill

The summit area of this hill consists of three tops with LIDAR analysis giving two of these tops within 1mm of each other: 

 

367.818m at SO 13829 89079 

367.819m at SO 13711 88853 

 

These two tops and an intermediary third top were surveyed with the Trimble GeoXH 6000, resulting in the following heights and positions: 

 

367.942m at SO 13828 89079 

367.252m at SO 13754 88924 

368.031m at SO 13710 88852 

 

As the summit has now been surveyed with the Trimble GeoXH 6000 it is this result that is being prioritised for listing purposes, 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 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. 

The Trimble GeoXH 6000 gathering data at the old summit position of Pen Aran Hill

The Trimble GeoXH 6000 gathering data at the new summit position of Pen Aran Hill
 

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 368.0m and this is positioned at SO 13710 88852, 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 240 metres south-westward from where the previously listed summit is positioned. 

 

The full details for the hill are:

Group:  Cilfaesty

Name:  Pen Aran Hill 

OS 1:50,000 map:  136

Summit Height:  368.0m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference (New Position):  SO 13710 88852 (Trimble GeoXH 6000) 

Bwlch Height:  324.6m (LIDAR) 

Bwlch Grid Reference:  SO 13561 88411 (LIDAR) 

Drop:  43.4m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

Myrddyn Phillips (October 2021)