Saturday, 24 December 2022

Mapping Mountains – Summit Relocations – The Fours – The 400m Hills of England


Lag Bank (SD 249 942) 

There has been a Summit Relocation 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 Lag Bank (SD 249 942)

The criteria for the list that this summit relocation applies to 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 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 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 y Myrddyn Phillips and Aled Williams

The name the hill is listed by is Lag Bank, and it is adjoined to the The Old Man of Coniston group of hills, which are situated in the southern fells of the Lake District, and it is positioned with a minor road to its north-west and the A593 road to its south-east, and has the village of Coniston towards the north-east.

Extract from the Ordnance Survey 1:25.000 Explorer map

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 listed with 30m of drop, based on the 411m summit spot height positioned at SD 25078 94336 and the 381m col spot height which appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage 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 the 410.4m point positioned at SD 25083 94336

LIDAR analysis gives the highest ground on this hill as 411.2m positioned at SD 24996 94270, as opposed to 410.4m positioned at SD 25083 94336 and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to when the high point is positioned in a different field, to a different feature such as a conifer plantation, within a different map contour, a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 411.2m and this is positioned at SD 24996 94270.  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 approximately 85 metres south-westward from where the previously listed summit is positioned. 

 

The full details for the hill are:

Group:  The Old Man of Coniston

Name:  Lag Bank

OS 1:50,000 map:  96

Summit Height:  411.2m (LIDAR)

Summit Grid Reference (New Position):  SD 24996 94270 (LIDAR)

Col Height:  380.85m (LIDAR)

Col Grid Reference:  SD 25214 94767 (LIDAR)

Drop:  30.3m (LIDAR)

 

Myrddyn Phillips and Aled Williams (December 2022) 

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