Mapping Mountains – Summit Relocations – Y Trichant – The 300m Hills of Wales and Y Pedwarau – The 400m Hills of Wales

Lan Ucha Ty’n y Wern (SN 996 423) 

There has been a Summit Relocation to a hill that is listed in the Y Trichant – The 300m Hills of Wales and the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis initially conducted by Aled Williams and subsequently by Myrddyn Phillips. 

LIDAR image of Lan Ucha Ty'n y Wern (SN 996 423)

The criteria for the lists this summit relocation affects 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, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

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

Y Pedwarau – The 400m Hills of Wales – Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list are five categories of sub hills, with this hill listed in the 390m Sub-Pedwar category.  The criteria for this category are all Welsh hills at or above 390m and below 400m in height that have 30m minimum drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is now listed by is Lan Ucha Ty’n y Wern 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 the B4519 road to its north-east and a minor road to its south, and has the small community of Capel Uchaf (Upper Chapel) towards the south-east.

When the original 300m 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 398m summit height, based on the spot height positioned at SN 996 423 that appears on the contemporary Ordnance Survey 1:25,000 Explorer map. 

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 396.9m positioned at SN 99625 42340.  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 Lan Ucha Ty'n y Wern (SN 996 423)

The height produced by LIDAR analysis to the natural summit of this hill is 396.7m positioned at SN 99632 42324, and this position in relation to raised field boundary 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 396.7m and this is positioned at SN 99632 42324, this position is close to where the 398m spot height appears on the Ordnance Survey 1:25,000 Explorer map, and is approximately 16 metres south-eastward from where the high point of the raised field boundary is positioned. 

 

The full details for the hill are:

Group:  Mynydd Epynt 

Name:  Lan Ucha Ty’n y Wern 

OS 1:50,000 map:  147, 160

Summit Height:  396.7m (LIDAR)                                                           

Summit Grid Reference (New Position):  SN 99632 42324 (LIDAR) 

Bwlch Height:  362.65m (LIDAR) 

Bwlch Grid Reference:  SN 99601 42833 (LIDAR) 

Drop:  34.1m (LIDAR) 

 

Myrddyn Phillips and Aled Williams (July 2024)