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

Moel Eglwys (SH 905 479)  

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 summit survey conducted by Myrddyn Phillips and Aled Williams and LIDAR bwlch analysis conducted by Myrddyn Phillips. 

The summit of Moel Eglwys (SH 905 479)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list are five categories of sub hills; 500m Sub-Pedwarau, 500m Double Sub-Pedwarau, 400m Sub-Pedwarau, 390m Sub-Pedwarau and the 390m Double Sub-Pedwarau.  The list is co-authored by Myrddyn Phillips and Aled Williams and is 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 Moel Eglwys, and it is adjoined to the Carnedd y Filiast group of hills, which are situated in the central part of North Wales (Region C1, Sub-Region C1A), and it is positioned encircled by minor roads, with the A5 road to its north, and has the village of Cerrigydrudion towards the east north-east.

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was listed with an estimated c 36m of drop, based on the 448m summit spot height positioned at SH 90549 47807 that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated c 412m bwlch height, based on interpolation of 10m contouring between 410m - 420m.

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

However, it was not until the survey with the Trimble GeoXH 6000 that the summit details for this hill could be accurately re-assessed.

The Trimble survey gives the highest ground on this hill as 447.6m positioned at SH 90580 47962, as opposed to the Trimble giving 447.4m positioned at SH 90552 47811, and this 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 found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour either on Ordnance Survey maps or interactive mapping, 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 considered a relatively recent man-made construct, or the de-twinning of a summit, 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 set-up position at the summit of Moel Eglwys (SH 905 479)

Gathering data at the old summit position of Moel Eglwys (SH 905 478)

Therefore, the height produced by the Trimble GeoXH 6000 survey to the summit of this hill is 447.6m and is positioned at SH 90580 47962.  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 150 metres northward from the position of the map spot height and the previously listed summit position.

The full details for the hill are:

Group:  Carnedd y Filiast

Name:  Moel Eglwys

OS 1:50,000 map:  116

Summit Height:  447.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference (New Position):  SH 90580 47962 (Trimble GeoXH 6000)

Bwlch Height:  410.9m (LIDAR)

Bwlch Grid Reference:  SH 90043 48234 (LIDAR) 

 

Drop:  36.6m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Myrddyn Phillips and Aled Williams (September 2014)