Thursday 15 September 2022

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


Long Crags (NT 955 214) 

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 by Joe Nuttall who produced a summit analysis programme using LIDAR, and then by LIDAR analysis conducted by Myrddyn Phillips. 

Long Crags (NT 955 214). Photo: Aled Williams

The criteria for the list this height revision affects are:

The FoursThe 400m Hills of England.  English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main listing of The Fours are three categories of sub hills, with this hill being 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 2nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24th April 2018.

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

The name the hill is listed by is Long Crags, and it is adjoined to the The Cheviot group of hills, which are situated in Northumberland (Region 33: Scottish Border to the River Tyne), and it is positioned with a minor road to its north and the A697 road to its east, and has the town of Wooler towards the north north-east.

When the 2nd edition of the The Fours – The 400m Hills of England was published by Mapping Mountains Publications in April 2018, this hill was not included in the accompanying sub list, as it was considered not to meet the criteria used for this sub category.

During the updating of this list for the 2nd edition this hill was noted and listed with 18m of drop, based on the 432m summit spot height positioned at NT 95699 21058 that appears on the Ordnance Survey 1:50,000 Lanranger and 1:25,000 Explorer map and the 414m col 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 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 image of Long Crags (NT 955 214)

LIDAR analysis gives this hill a summit height of 439.5m positioned at NT 95597 21432 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. 

LIDAR summit image of Long Crags (NT 955 214)

Therefore, the new listed summit height of this hill is 439.5m and this was derived from LIDAR analysis, this is 7.5m higher than its previously listed height of 432m which appears as a spot height on the Ordnance Survey 1:50,000 Lanranger and 1:25,000 Explorer map. 

 

The full details for the hill are:

Group:  The Cheviot

Name:  Long Crags

OS 1:50,000 map:  74, 75

Summit Height (New Height):  439.5m (LIDAR)

Summit Grid Reference:  NT 95597 21432 (LIDAR)

Col Height:  415.8m (LIDAR)

Col Grid Reference:  NT 95503 20955 (LIDAR)

Drop:  23.7m (LIDAR)

 

Our thanks to Ronnie Bowron for bringing the details of this hill to our attention.

Myrddyn Phillips and Aled Williams (September 2022)

 

 

 

  

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