Friday 17 July 2015

Mapping Mountains – Summit Relocations – Y Pedwarau - The 400m Hills of Wales


Little Hill (SO 171 537)

There has been a Summit Relocation to a hill that is listed in the Y Pedwarau – The 400m Hills of Wales, 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.

Little Hill (SO 171 537)

The criteria for the list that this summit relocation applies to are: 

Y PedwarauThe 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, the list is co-authored by Myrddyn Phillips and Aled Williams and is now published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Little Hill and it is adjoined to the Fforest Glud group of hills, which are situated in the easterly part of South Wales (Region B, Sub-Region B3), and it is positioned with the A481 road to its north-west, a mino road to its south and the B4594 to its east, and has the small community of Glascwm towards the south-east.

When the 1st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was listed with 46m of drop, based on the 469m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map at SO 17269 53775 and the 423m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.


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

However, this hill has another high point which is approximately 100 metres west from where the 469m spot height appears on the ground.  Both positions were surveyed with the Trimble GeoXH 6000, resulting in:


469m spot height position:  469.0m at SO 17268 53774

non-spot heighted position:  469.2m at SO 17175 53749

In relation to the previously listed summit position the high point determined by the Trimble GeoXH 6000 survey comes within the parameters of the Summit Relocations used within this page heading, these parameters are: 

The term Summit Relocations applies when the high point of the hill is foundeter to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.


The Trimble GeoXH 6000 gathering data at the new summit position of Little Hill, with the old position of the summit just on the left of centre in the background of this photo

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 469.2m and this is positioned at SO 17175 53749, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 100 metres westward from where the previously listed summit is positioned.

 

The full details for the hill are:

Group:  Gwaun Ceste

Name:  Little Hill

OS 1:50,000 map:  148

Summit Height:  469.2m (converted to OSGM15)

Summit Grid Reference (New Position):  SO 17175 53749 
 
Bwlch Height:  422.7m (converted to OSGM15)

Bwlch Grid Reference:  SO 16357 54404

Drop:  46.5m


Myrddyn Phillips and Aled Williams (July 2015)



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