Thursday, 24 May 2018

Mapping Mountains – Summit Relocations – The Fours

Knot (NY 650 091)

There has been a Summit Relocation to a hill that is listed in The Fours initiated by LIDAR analysis conducted by Myrddyn Phillips.  The Fours is the title for the list of 400m hills of England and is co-authored by Myrddyn Phillips and Aled Williams with the 2nd edition of the booklet containing this list published by Mapping Mountains Publications on the 24.04.18.

The criteria for the list that this summit relocation affects are:

English hills at and above 400m and below 500m in height that have a minimum 30m of drop.

The name of the hill is Knot and it is situated in The Northern and Central Pennines (Region 35, Section 35A), and is positioned with the A66 road to its north-east, the M6 to its west and the A685 road to its south and has a number of minor roads encircling it, and has the small community of Orton towards the west south-west and Great Asby towards the north-east.

As the upper section of the hill is a part of designated open access land an ascent is feasible from most directions with public footpaths leading to the open access land from the south, west, north and east.

The summit area of this hill has two uppermost 410m ring contours, and in the 1st edition of The Fours published by Europeaklist in December 2013, and prior to LIDAR analysis, the position of this hill’s summit was listed as NY 646 092, this position was to a triangulation pillar given a 412m map height which is positioned in the western most 410m ring contour, whilst the eastern most ring contour has a second 412m map heighted top positioned at NY 651 090 and which is mentioned in the accompanying Notes section of the 1st edition.

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website with the summit position circled

The highest land in each of these ring contours was analysed via LIDAR by Myrddyn Phillips.  The LIDAR (Light Detection & Ranging) technique is highly accurate height data that is now freely available for much of England and Wales. 

The LIDAR analysis gives the hill the following details:

Western most ring contour, land adjacent to trig pillar

LIDAR:  412.285m at NY 64697 09213 and NY 64695 09205

Eastern most ring contour:

LIDAR:  412.940m at NY 65065 09121

Therefore, the confirmation of the relocated summit position is at NY 65065 09121 and this consists of closely cropped grass adjacent to a stone wall, this position is approximately 385 metres east south-eastward from where the previous prioritised 412m map heighted summit was given in the 1st edition of The Fours.

The full details for the hill are:

Cardinal Hill:  Knot

Summit Height:  412.9m (LIDAR)

Name:  Knot

OS 1:50,000 map:  91

Summit Grid Reference (New Position):  NY 65065 09121 (LIDAR)
Drop:  c 120m

Myrddyn Phillips and Aled Williams (May 2018)

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