Mapping Mountains – Significant Height Revisions – Tumps

Caus Castle (SJ 337 077)

There has been a Significant Height Revision 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 significant height revision 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 hills, which 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 42m of drop, based on the 223m summit spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and used to appear on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and a 181m col height.

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 image of Caus Castle (SJ 337 077)

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 comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:

The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 232.1m and this was derived from LIDAR analysis, with its summit position derived from a Trimble GeoXH 6000 survey.  This is 9.1m higher than the previously listed summit height of 223m which was based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map.

The full details for the hill are:

Group:  Stiperstones

Name:  Caus Castle

OS 1:50,000 map:  126

Summit Height (New Height):  232.1m (LIDAR)

Summit Grid Reference:  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 (September 2015)