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

Chrome Hill (SK 070 673) 

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 Chrome Hill (SK 070 673)

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, 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 Chrome Hill, and it is adjoined to the Axe Edge group of hills, which are situated in the Peak District, and it is positioned with minor roads to its north-west, south and east, and the B5053 road farther to its east, and has the town of Buxton towards the north north-west. 

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, this hill was listed with a 443m summit height, 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. 

Extract from the DataMapWales showing a 439m summit spot height

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 Chrome Hill (SK 070 673)

LIDAR analysis gives the highest ground on this hill as 439.2m positioned at SK 07062 67341, 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 439.2m and this was derived from LIDAR analysis, this position is close to where the spot height appeared and is 3.8m lower than the previously listed 443m summit height, which appeared as a spot height on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

 

The full details for the hill are:

Group:  Axe Edge

Name:  Chrome Hill

OS 1:50,000 map:  119

Summit Height (New Height):  439.2m (LIDAR)

Summit Grid Reference:  SK 07062 67341 (LIDAR)

Col Height:  382.2m (LIDAR)

Col Grid Reference:  SK 06904 67591 (LIDAR)

Drop:  57.0m (LIDAR)

 

Myrddyn Phillips and Aled Williams (October 2023)