Mapping Mountains – Significant Height Revisions – Y Trichant – The 300m Hills of Wales

 

Aston Hill (SO 296 900) 

There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Aston Hill (SO 296 900)

The criteria for the list that this height revision applies to are:

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Aston Hill, and it is adjoined to the Cilfaesty group of hills, which are situated in the north-eastern part of South Wales (Region C2, Sub-Region C2B), and it is positioned encircled by minor roads, with the B4385 road farther to its north-east, and has the town of Bishop’s Castle towards its south-east.

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed with a 379m summit height based on the spot height positioned at SO 29659 90041 that appears on the 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. 

LIDAR summit image of Aston Hill (SO 296 900)

The summit height produced by LIDAR analysis is 380.0m positioned at SO 29663 90049, 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, Harvey or other interactive 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 with the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 380.0m and this was derived from LIDAR analysis, this is 1.0m higher than the previously listed summit height of 379m, which was based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map, and importantly indicates that this map is missing an uppermost 380m ring contour.

 

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Cilfaesty

Name:  Aston Hill

OS 1:50,000 map:  137

Summit Height (New Height):  380.0m (LIDAR)

Summit Grid Reference:  SO 29663 90049 (LIDAR)  

Bwlch Height:  341.8m (LIDAR)

Bwlch Grid Reference:  SO 28966 89594 (LIDAR)

Drop:  38.2m (LIDAR)

 

Myrddyn Phillips (September 2026)