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

Purdom Pikes (NY 604 919) 

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 LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Purdom Pikes (NY 604 919)

The criteria for the list that this summit relocation 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; the 400m Sub-Four category, the 390m Sub-Four category and the 390m Double Sub-Four category.  The list is co-authored by Myrddyn Phillips and Aled Williams and the 2^nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24^th April 2018.

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

The name the hill is listed by is Purdom Pikes, and it is adjoined to the Sighty Crag group of hills, which are situated in the north-eastern part of England, and it is positioned with the B6357 road to its north-west and a minor road to its north-east, and has the village of Kielder towards the north-east.

When the 2^nd edition of the The Fours – The 400m Hills of England was published by Mapping Mountains Publications in April 2018, this hill was listed with 45m of drop, based on the 454m summit spot height adjoined to a triangulation pillar positioned at NY 60568 91945 and the 409m col spot height that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

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. 

LIDAR summit image of Purdom Pikes (NY 604 919)

LIDAR analysis gives the highest ground on this hill as 454.0m positioned at NY 60466 91924, 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.

Therefore, the summit height produced by LIDAR analysis is 454.0m and this is positioned at NY 60466 91924.  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 approximately 100 metres westward from where the previously listed summit is positioned. 

 

The full details for the hill are:

Group:  Sighty Crag

Name:  Purdom Pikes

OS 1:50,000 map:  80

Summit Height:  454.0m (LIDAR)

Summit Grid Reference (New Position):  NY 60466 91924 (LIDAR)

Col Height:  408.3m (LIDAR)

Col Grid Reference:  NY 59262 92033 (LIDAR)

Drop:  45.7m (LIDAR)

 

Myrddyn Phillips and Aled Williams (December 2022)