Thursday 9 July 2015

Mapping Mountains – Summit Relocations – Tumps


Caus Castle (SJ 337 077)

There has been confirmation of a Summit Relocation to a hill that is listed in the Tumps (thirty & upward metre prominences)with the summit height, col height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey and subsequent LIDAR analysis conducted by Myrddyn Phillips.

Caus Castle (SJ 337 077)

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

Tumps.  All hills in Britain that have 30m minimum drop, irrespective of their height.  The list is authored by Mark Jackson and is published and maintained by the DoBIH.

The summit cone of Caus Castle (SO 337 077)

The name the hill is listed by is CausCastle, and it is adjoined to the Stiperstones group of hillswhich are situated in the county of Shropshire close to the Welsh border, and it is positioned with a minor road to its immediate north-west, the A458 road to its north and the B4386 road to its east, and has the village of Westbury towards the north-east.

Prior to the survey with the Trimble GeoXH 6000 this hill was listed with a 223m summit height based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and which is positioned at SJ 33772 07836.


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

However, it was not until the Trimble GeoXH 6000 survey and subsequent LIDAR analysis that the details for this hill could be accurately 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 Caus Castle (SJ 337 077)

LIDAR analysis gives the highest ground on this hill as 232.1m with the Trimble giving the summit positioned at SJ 33713 07792, and this position in relation to the position of the 223m spot height 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 summit where the 223m Ordnance Survey spot height appears

The Trimble GeoXH 6000 on the summit of Caus Castle

Therefore, the summit height produced by LIDAR analysis is 232.1m with the Trimble GeoXH 6000 giving the summit positioned at SJ 33713 07792.  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 positioned to a different feature and is approximately 70 metres south-westward from where the 223m spot height appears.

The full details for the hill are:

Group:  Stiperstones

Name:  Caus Castle

OS 1:50,000 map:  126

Summit Height:  232.1m (LIDAR)

Summit Grid Reference (New Position):  SJ 33713 07792 (Trimble GeoXH 6000)

Col Height:  180.4m (converted to OSGM15, Trimble GeoXH 6000)

Col Grid Reference:  SJ 33384 07622 (Trimble GeoXH 6000)

Drop:  51.7m (LIDAR summit and Trimble GeoXH 6000 col)


Myrddyn Phillips (April 2015)


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