Mapping Mountains – Summit Relocations – Y Pellennig - The Remotest Hills of Wales and Y Pedwarau – The 400m Hills of Wales

Gwryd (SN 935 401)

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

LIDAR image of Gwryd (SN 935 401)

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

Y Pellennig –The Remotest Hills of Wales.  Welsh hills whose summit is at least 2.5km from the nearest paved public road and the hill has a minimum 15m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is available as a downloadable e-booklet or print-booklet version on Mapping Mountains Publications with the up-to-date master list available on Mapping Mountains to download in Google Doc format. 

Y Pellennig - The Remotest Hills of Wales by Myrddyn Phillips and Aled Williams

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 400m Sub-Pedwar category.  The criteria for which is all Welsh hills at or above 400m and below 500m in height that have 20m or more and below 30m of 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 listed by is Gwryd and it is adjoined to the Mynydd Epynt group of hills, which are situated in the central part of South Wales (Region C2, Sub-Region C2A), and it is positioned with the A483 road to its north-west, the A40 road to its south and the B4520 road to its east, and has the small community of Capel Uchaf (Upper Chapel) towards the east.

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013 this hill was included in the 400m Sub-Pedwar category with 21m of drop, based on the 453m summit height that appears as a spot height on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and which is positioned at SN 93377 39743, and a 432m bwlch height that appears as a spot height on the Ordnance Survey 1:25,000 Explorer map.

Extract from the Ordnance Survey 1:25,000 Explorer map

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on other publicly available Ordnance Survey maps and showed a 456m summit spot height for this hill positioned at SN 93588 40204.  This spot height is also shown on Ordnance Survey data that appears on the Magic Maps website.   

Extract from the Magic Maps website

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.

The summit height produced by LIDAR analysis is 456.2m positioned at SN 93574 40197, as opposed to 453.6m positioned at SN 93431 39770 which is in the vicinity of where the 453m spot height appears, 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 either on Ordnance Survey maps or interactive mapping, 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 the listing of a new twin summit or de-twinning of a summit, 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.

LIDAR summit image of Gwryd (SN 935 401)

Therefore, the new listed summit height of this hill is 456.2m positioned at SN 93574 40197 and this was derived from LIDAR analysis.  This position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, but matches the approximate position of the 456m spot height that appears on the Magic Maps website, and is approximately 500 metres north north-eastward from where the previously listed summit is positioned.

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Mynydd Epynt

Name:  Gwryd

OS 1:50,000 map:  160

Summit Height:  456.2m (LIDAR)

Summit Grid Reference (New Position):  SN 93574 40197 (LIDAR) 

 

Bwlch Height:  433.1m (LIDAR)

Bwlch Grid Reference:  SN 93833 41666 (LIDAR)

Drop:  23.1m (LIDAR)

Remoteness:  3.100km

Myrddyn Phillips and Aled Williams (March 2020)