Thursday, 7 June 2018

Mapping Mountains – Hill Reclassifications – The Fours


Shovel Down (SX 658 857) – 400m Sub-Four deletion

There has been a deletion from the listing of The Fours due to LIDAR analysis conducted by Aled Williams.  The Fours is the title for the list of 400m hills of England and takes in all English hills at and above 400m and below 500m in height that have a minimum 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.

Accompanying the main list of The Fours are three categories of sub hills, with this hill being deleted from the 400m Sub-Fours.  The criteria for 400m Sub-Four status are all English hills at and above 400m and below 500m in height that have 20m and more and below 30m of drop. 
 
Prior to LIDAR analysis this hill was listed with c 21m of drop based on a 1,427ft (435.0m) summit height that appears on the Ordnance Survey 1:10,560 map and an estimated col height of c 414m based on col contouring between 410m – 420m on the 1:50,000 Landranger and 1:25,000 Explorer maps, with the col contours between 410m – 415m on OS Maps, which is the recent replacement for OS Get-a-map.

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

The name of the hill is Shovel Down and it is situated in Dartmoor which is a part of the Cornwall and Devon region that constitutes Region 40, with its Cardinal Hill being High Willhays (SX 580 892), the hill is positioned above the Fernworthy Reservoir which is to its south south-east and has the market town of Chagford to its east north-east.

As the summit of the hill is a part of designated open access land it can be approached from a number of directions, with the nearest public road giving immediate access on to the open access land being to the north north-east of the summit.

The deletion of Shovel Down from 400m Sub-Four status is due to LIDAR analysis conducted by Aled Williams.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.


Aled’s LIDAR analysis gives the hill the following details:

Shovel Down

Summit Height:  432.6m

Summit Grid Reference:  SX 65846 85742

Col Height:  413.5m

Col Grid Reference:  SX 66236 86007

Drop:  19.1m


Therefore, the 432.6m LIDAR analysis for the summit position at SX 65846 85742 and the 413.5m LIDAR analysis for the col position at SX 66236 86007 gives this hill 19.1m of drop, which is insufficient for it to retain its 400m Sub-Four status.


The full details for the hill are:

Cardinal Hill:  High Willhays

Summit Height:  432.6m (LIDAR)

Name:  Shovel Down

OS 1:50,000 map:  191

Summit Grid Reference:  SX 65846 85742 (LIDAR)

Drop:  19.1m (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:










Myrddyn Phillips and Aled Williams (June 2018)

No comments: