Mapping Mountains – Significant Height Revisions – The Fours – The 400m Hills of England

Mid Fell (NY 580 492) 

There has been a Significant Height Revision 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 Mid Fell (NY 580 492)

The criteria for the list this height revision affects 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 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 Mid Fell, and it is adjoined to the Cross Fell group of hills, which are situated in the northern Pennines, and it is positioned with the B6413 road to its west and the A689 road to its east, and has the small village of Cumrew towards the west north-west.

This hill appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map without a summit spot height and with an uppermost 440m ring contour. 

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

When the 2^nd edition of the The Fours – The 400m Hills of England was published by Mapping Mountains Publications in April 2018, the height of this hill was listed as 450m with its summit positioned at NY 580 492, based on the spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.

One of the mapping resources now available online is the WalkLakes website which hosts an interactive map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available maps and the 450m spot height is also given on the summit area of this hill. 

Extract from the interactive mapping hosted on the WalkLakes website

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 Mid Fell (NY 580 492)

LIDAR analysis gives the highest ground on this hill as 450.6m positioned at NY 58031 49245, 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 450.6m and this was derived from LIDAR analysis, 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 10.6m higher than the uppermost 440m ring contour that appears on these maps. 

 

The full details for the hill are:

Group:  Cross Fell

Name:  Mid Fell

OS 1:50,000 map:  86

Summit Height (New Height):  450.6m (LIDAR)

Summit Grid Reference:  NY 58031 49245 (LIDAR)

Col Height:  423.8m (LIDAR)

Col Grid Reference:  NY 58299 49034 (LIDAR)

Drop:  26.9m (LIDAR)

 

Myrddyn Phillips and Aled Williams (January 2023)