Friday 6 October 2017

Mapping Mountains – Hill Reclassifications – Humps


Foel (SH 450 506) – Subhump reclassified to Hump

This is the seventeenth in a series of Hill Reclassification posts that detail hills whose status has been altered in the listing of the Humps (HUndred Metre Prominences) through map study and / or surveys that I have instigated.

Foel (SH 450 506)

This and forthcoming posts are retrospective as many of these hill reclassifications were initiated from studying the Ordnance Survey enlarged mapping that is hosted on the Geograph website, or in this instance from a survey with the Trimble GeoXH 6000, and for the reclassifications that affected the Humps the first survey of this hill took place on the 30.12.13.

The listing of Humps was published in book format by Lulu in 2009 and entitled More Relative Hills of Britain, its author; Mark Jackson gives credit to a number of people who contributed toward the formation of this list, these include; Eric Yeaman, Alan Dawson, Clem Clements, Rob Woodall, Bernie Hughes, Pete Ridges and others.  When the list was published in book format there were 2987 Humps listed with their criteria being any British hill that has 100m or more of drop, accompanying the main list is a sub category entitled Subhumps, with the criteria being any British hill that has 90m or more and below 100m of drop.

More Relative Hills of Britain by Mark Jackson


The details for the reclassification appear below:

There has been a reclassification to the listing of the Humps (HUndred Metre Prominences) instigated by a survey with the Trimble GeoXH 6000 and which was later confirmed by a survey with the Leica GS15.

Prior to the survey with the Trimble GeoXH 6000 Mark Jackson had listed this hill as a Subhump with c 99m of drop based on the 223m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 124m based on bwlch contouring at 10m intervals. 

The hill is adjoined to the Moel Hebog group of hills and is situated overlooking the A 487 road which is to its east and the Afon Llyfni which is to its north, with the small community of Pen-y-groes to the north-east and Clynnog Fawr to the west south-west.

Foel was surveyed using a Trimble GeoXH 6000 by Myrddyn Phillips on the 30.12.13 resulting in a 100.9m drop value, the hill was then re-surveyed with the Trimble GeoXH 6000 on the 02.02.14 resulting in a 101.6m drop value, it was then again re-surveyed on the 16.02.14 by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica GS15 and Trimble GeoXH 6000 resulting in a 101.2m and 101.1m drop value respectively, which is sufficient for this hill to be reclassified from Subhump to Hump status.



The reclassification of this hill from Subhump to Hump status was accepted by Mark Jackson and its new classification augmented in to the listing of the Humps in February 2014.

Gathering data with the Trimble GeoXH 6000 at the summit of Foel

The full details for the hill are:


Name:  Foel

Summit Height:  221.3m (as listed in the Humps, 221.4m converted to OSGM15)

OS 1:50,000 map:  115, 123

OS 1:25,000 map:  254

Summit Grid Reference:  SH 45025 50677

Drop:  101.2m (converted to OSGM15)



Myrddyn Phillips (October 2017)

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