Mapping Mountains – Hill Reclassifications – The Fours - The 400m Hills of England

Knott (SD 676 940) – 400m Sub-Four deletion

There has been a deletion to the listing of 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 initially conducted by Aled Williams and subsequently by Myrddyn Phillips. 

LIDAR image of Knott (SD 676 940)

The criteria for the list that this deletion 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, with this hill being deleted from 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 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 Knott and it is adjoined to the The Calf group of hills, which are situated in the Howgill Fells in the Yorkshire Dales, and it is positioned with the A683 road to its south-east and the A684 road to its south-west, and has the town of Sedbergh towards the south-west.

Prior to LIDAR analysis this hill was listed with an estimated c 20m of drop, based on a 429m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated c 409m col height, based on interpolation of contouring between 400m - 410m, and latterly between 405m - 410m that appeared on the interactive mapping on the OS Maps website.

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.

Therefore, the deletion of this hill from 400m Sub-Four status is due to LIDAR analysis, resulting in a 429.7m summit height and a 410.0m col height, with these values giving this hill 19.7m of drop, which is insufficient for it to be classified as a 400m Sub-Four.

The full details for the hill are:

Group:  The Calf

Name:  Knott

OS 1:50,000 map:  98

Summit Height:  429.7m (LIDAR)

Summit Grid Reference:  SD 67644 94087 (LIDAR)

Col Height:  410.0m (LIDAR)

Col Grid Reference:  SD 67446 94201 (LIDAR)

Drop:  19.7m (LIDAR)

For the additions, deletions and reclassifications to The Fours – The 400m Hills of England reported on Mapping Mountains since the December 2013 publication of the 1^st edition of this list by Europeaklist please consult the following Change Registers:

The Fours

The Fours – 400m Sub-Four

The Fours – 390m Sub-Four

The Fours – 390m Double Sub-Four

Myrddyn Phillips and Aled Williams (May 2018)