Great Creigiau (SO 198 636)
There has been a Significant Height Revision to a hill that was considered for inclusion in the list of The Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams.
Great Creigiau (SO 198 636) |
The Welsh Highlands –
Uchafion Cymru
– This is the revised draft title for the Welsh 500m P15s list that takes
in all hills in Wales at or above 500m in height with 15m minimum drop. Accompanying the main list are three sub
lists, these are; 500m Sub-Uchaf, 490m Sub-Uchaf and the Double Sub category,
with this hill being considered for 500m Sub-Uchaf satus. The criteria for which are all Welsh hills at
or above 500m in height with 14m or more and below 15m of drop. The list is co-authored by Myrddyn Phillips
and Aled Williams with the Introduction to the list being published on Mapping Mountains in November 2015 and an update relating to the list appearing on Mapping Mountains on the 19th June 2019.
The Welsh Highlands - Uchafion Cymru by Myrddyn Phillips and Aled Williams |
This hill was not included as a P14 Sub in the original list of Welsh 500m P15s that later became known as Yr Uchafion and latterly as The Welsh Highlands – Uchafion Cymru, as with a 646m summit spot height and bwlch contouring between 630m – 640m that appear on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, this contouring implied that the hill did not have sufficient drop to be considered for P14 500m Sub-Uchaf status.
Extract from the Ordnance Survey 1:25,000 Explorer map |
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.
The Trimble GeoXH 6000 gathering data at the summit of Great Creigiau |
The full details for the hill are:
Group: Fforest Glud
Name: Great Creigiau
OS 1:50,000 map: 148
Summit Height (New Height):
643.4m (converted to OSGM15)
Summit Grid Reference:
SO 19810 63643
Bwlch Height: 633.3m (converted
to OSGM15)
Bwlch Grid Reference:
SO 19959 63879
Drop: 10.1m
Myrddyn Phillips and Aled Williams (August 2021)
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