Mapping Mountains – Summit Relocations – The Fours - The 400m Hills of England

Willstone Hill (SO 485 943)

There has been a Summit Relocation to a hill that is listed in the The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips with assistance from Mark Trengove and Bob Kerr. 

Willstone Hill (SO 485 943)

The criteria for the list that this name change applies to are: 

The Fours – The 400m Hills of England.  English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list are three categories of sub hills, with this hill included in the 400m Sub-Four category, the criteria for which are all English 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, with the 1^st edition of the booklet containing this list published by Europeaklist in December 2013 and by Haroldstreet in January 2014.

The Fours - The 400m Hills of England by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Willstone Hill and it is adjoined to the Stiperstones group of hills, which are situated in the county of Shropshire close to the Welsh border, and it is positioned with a minor road to its north-east and east, the A49 road to its west and the B4371 road to its south, and has the town of Church Stretton towards the west south-west.

When the 1^st edition of the The Fours was published by Europeaklist in December 2013, this hill was listed with an estimated c 20m of drop, based on the 403m summit spot height positioned at SO 48529 94339 that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and an estimated c 383m col height, based on interpolation of 5m contouring between 380m - 385m.

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

However, it was not until the survey with the Trimble GeoXH 6000 and subsequent LIDAR analysis that an accurate height and position could be attained for the heath land summit that the spot height is adjoined to and a rock outcrop that is not given a spot height on either the Ordnance Survey 1:50,000 Landranger or the 1:25,000 Explorer map.

Bob on the summit of Willstone Hill

The Trimble GeoXH 6000 gathering data at the summit of Willstone Hill (SO 485 943)

The Trimble GeoXH 6000 survey gives the highest ground on this hill as 404.65m positioned at SO 48564 94370, this is adjoined to a small rock outcrop.  Whilst subsequent LIDAR (Light Detection & Ranging) analysis gives the highest ground on the adjacent heath land summit where the 403m spot height appears as 404.2m positioned at SO 48537 94344, 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.

LIDAR image of Willstone Hill (SO 485 943)

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 404.65m and this is positioned at SO 48564 94370.  This position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and the 1:25,000 Explorer map and is to a different feature approximately 57 metres north-eastward from where the 403m spot height appears and from where LIDAR gives the high point of the adjoined heath land summit to be positioned.

The full details for the hill are:

Group:  Stiperstones

Name:  Willstone Hill

OS 1:50,000 map:  137, 138

Summit Height:  404.65m (converted to OSGM15)

Summit Grid Reference (New Position):  SO 48564 94370

  

Col Height:  382.2m (converted to OSGM15)

Col grid Reference:  SO 48190 94230

Drop:  22.4m

Myrddyn Phillips and Aled Williams (October 2016)