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

Pt. 404.4m (SK 073 698) – 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 detail on contemporary maps produced from Ordnance Survey data and subsequently confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Pt. 404.4m (SK 073 698)

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 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 hill is being listed by the point (Pt. 404.4m) notation and it is adjoined to the Axe Edge group of hills, which are situated in the Peak District, and it is positioned with the A515 road to its north-east and has the town of Buxton towards the north north-west.

When the 1^st edition of the The Fours was published by Europeaklist in December 2013, this hill was included as a 400m Sub-Four and listed with an estimated c 22m of drop, based on the 405m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 383m col height based on interpolation of 5m contouring between 380m – 385m.  However, as the col is on land that is a part of the Hillhead Quarry the 1:50,000 and 1:25,000 maps do not show continuous contouring. 

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

One of the resources recently available online is the mapping on the OS Maps website and the details for this hill were subsequently re-assessed against this mapping.  This is the replacement for OS Get-a-map and had contours at 5m intervals which were proving consistently more accurate compared to the 5m contours that sometimes appear on the Ordnance Survey 1:25,000 Explorer map and used to appear on the online Vector Map Local.  This mapping had col contouring between 385m – 390m, with interpolation placing the height of the col as an estimated c 386m, and when coupled with the 405m summit spot height these values gave this hill an estimated c 19m of drop. 

Extract from the interactive mapping hosted on the OS Maps 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.

Therefore, the deletion of this hill from 400m Sub-Four status is due to detail on contemporary maps produced from Ordnance Survey data and subsequent confirmation by LIDAR analysis, resulting in a 404.4m summit height and a 384.9m col height, with these values giving this hill 19.4m of drop, which is insufficient for it to be classified as a 400m Sub-Four.

The full details for the hill are:

Group:  Axe Edge

Name:  Pt. 404.4m

OS 1:50,000 map:  119

Summit Height:  404.4m (LIDAR)

Summit Grid Reference:  SK 07380 69895 (LIDAR)

Col Height:  384.9m (LIDAR)

Col Grid Reference:  SK 07349 69773 (LIDAR)

Drop:  19.4m (LIDAR)

For the additions, deletions and reclassifications to The Fours reported on Mapping Mountains since the December 2013 publication of the 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 (September 2018)