Mapping Mountains – Significant Height Revisions – The Fours – The 400m Hills of England

 

Saddle Tor (SX 750 764) 

There has been a Significant Height Revision 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 initially conducted by Aled Williams and subsequently by Myrddyn Phillips. 

LIDAR image of Saddle Tor (SX 750 764)

The criteria for the list this height revision affects 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 included in 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 name the hill is listed by is Saddle Tor, and it is adjoined to the Broad Barrow group of hills, which are situated in Dartmoor in the south-west of the country, and it is positioned with minor roads to its north, north-west and north-east, and the B3387 road to its immediate south, and has the town of Bovey Tracey towards the east north-east.

When the 1^st edition of the The Fours was published by Europeaklist in December 2013, this hill was listed with a 428m summit height, based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map. 

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.

When the 2^nd edition of The Fours – The 400m Hills of England was published by Mapping Mountains Publications in April 2018, the height of this hill was amended to 429.8m, based on analysis of available LIDAR. 

LIDAR summit image of Saddle Tor (SX 750 764)

Analysis of the latest available LIDAR gives the highest ground on this hill as 430.0m positioned at SX 75066 76407, and this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:

The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 430.0m and this was derived from analysis of the latest available LIDAR, this is 2.0m higher than its originally listed 428m summit height, which appears as a spot height on the contemporary Ordnance Survey 1:25,000 Explorer map. 

 

The full details for the hill are:

Group:  Broad Barrow

Name:  Saddle Tor

OS 1:50,000 map:  191

Summit Height (New Height):  430.0m (LIDAR)

Summit Grid Reference:  SX 75066 76407 (LIDAR)

Col Height:  402.4m (LIDAR)

Col Grid Reference:  SX 75260 76525 (LIDAR)

Drop:  27.7m (LIDAR)

 

Myrddyn Phillips and Aled Williams (March 2024)