Monday, 24 April 2023

Mapping Mountains - Summit Relocations – The 500-Metre Tops of England and Wales – Deweys


Dead Man’s Hill (SE 056 783) 

There has been a Summit Relocation to a hill that is listed in the The 500-Metre Tops of England and Wales, with the summit height, col height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Dead Man's Hill (SE 056 783)

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

The 500-Metre Tops of England and Wales are affectionately known after their hill list compiler; Michael Dewey.  This list mixes metric and imperial height in its criteria to bookend up to the 2000ft height band and takes in all hills in England, Isle of Man and Wales that are 500m and above and below 2000ft (609.6m) in height that have 30m minimum drop. 

Mountain tables by Michael Dewey

Michael Dewey died on the 5th November 2022.  His wife; Gillian wished for this list to be carried on and made provision for it to be co-authored by Myrddyn Phillips.  Michael will always be the compiler and originator, it’s just that he’s now got a co-author to safeguard and carry this list on.

The name the hill is listed by is Dead Man’s Hill, and it is adjoined to the Whernside group of hills, which are situated in the central Pennines, and it is positioned with minor roads to its north-west and south-east and the B6160 road to its west, and has the village of West Scrafton towards the north.

When the original list of Deweys appeared in the Mountain tables book published by Constable in 1995, this hill was listed with a summit height of 546m, based on the spot height positioned at SE 058 783 that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

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

This hill was subsequently surveyed with a Trimble GeoXH 6000 by Myrddyn Phillips on the 04.01.14, resulting in a 545.2m height positioned at SE 05813 78297.

The Trimble set-up position on the summit area of Dead Man's Hill 

However, it was not until LIDAR became available that the Trimble set-up position for the summit of 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 summit image of Dead Man's Hill

LIDAR close up summit image of Dead Man's Hill

The height produced by LIDAR analysis to the summit of this hill is 545.4m positioned at SE 05674 78329, as opposed to the Trimble set-up position which gave 545.2m positioned at SE 05813 78297.  These results and the highest ground LIDAR gives close to the Trimble set-up position appear below:

 

Trimble GeoXH 6000:  545.161m at SE 05813 78297 

LIDAR summit:  545.405m at SE 05674 78329 

LIDAR close to Trimble set-up position:  545.267m at SE 05791 78308 

 

The LIDAR result 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 judged to be 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 545.4m and this is positioned at SE 05674 78329, 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 approximately 150 metres westward from where the originally listed summit is positioned. 

 

The full details for the hill are: 

Group:  Whernside 

Name:  Dead Man’s Hill 

OS 1:50,000 map:  98

OS 1:25,000:  30, 298 

Summit Height:  545.4m (LIDAR) 

Summit Grid Reference (New Position):  SE 05674 78329 (LIDAR) 

Col Height:  483.3m (LIDAR) 

Col Grid Reference:  SE 04417 78278 (LIDAR) 

Drop:  62.1m (LIDAR) 

 

Myrddyn Phillips (April 2023)

 

 

  

No comments: