Hill Lists – Cymru / Wales
Y
Trechol - The Dominant Hills of Wales
Introduction
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Dinas Gynfor (SH 391 950) is situated in the Ynys Môn Group of hills and is listed as one of The Dominant Hills of Wales |
Listings of hills in Britain
have progressed since Sir Hugh Munro first compiled a list to the Scottish
3,000ft mountains that eponymously now bear his name of the Munros. Since Sir Hugh’s list was first published in
the 1891 Scottish Mountaineering Club Journal the concept of how to
differentiate one hill from another has developed with this association now
mainly relying upon what is referred to as prominence. This term is also known as reascent and drop,
with this being the height gain between summit and connecting bwlch to the
higher parent peak via the watershed.
Although differentiating one
hill from another mainly relies upon prominence, it is not the only tool used
to do so, as such criterion as distance, and height and prominence combined have
also been used. But prominence is now
the main criterion used to differentiate one hill from another.
The concept of prominence was
first investigated by the early hill list authors such as Corbett and Moss who
employed the use of a single ring contour in their listings. This system for cataloguing hills relied upon
maps of the day that were based on ring contours at 50ft intervals, therefore a
hill may be included that had a 5ft prominence or less because it had a
separate ring contour, this is an obvious failing in this system.
However, Corbett had
initialised the concept of objective judgment in how to make this all important
differentiation between one hill and another, whereas Munro relied upon
subjective judgment when he differentiated between his Separate Mountains (Munros)
and their Subsidiary Tops (Munro Tops).
This objective judgement took
its next stage forward when Carr and Lister used a 100ft criterion to
differentiate one hill from another in their book to ‘The Mountains of
Snowdonia’ which was published in 1925 by John Lane The Bodley Head Limited of
London. This use of 100ft by Carr and
Lister can be considered as the first objective height differentiation and therefore
the first use of how we now view the term prominence.
Although, as mentioned
previously, there have been other use of criterion to differentiate one hill from
another, there is a definite line between how the use of prominence has
evolved, this line can be viewed as a link, but this link does not have many
connecting parts to it, and up until the Dominant listing that this
Introduction details, that connecting part only involved one link, and that is
Relative Height, and now the second connecting link of Dominance has been added.
The difference between
Prominence and Relative Height can be summarised as the following, with the
explanation of Dominance then following:
Prominence
is applied to hills whose qualification also depends upon minimum height.
Relative
Height is applied to hills whose qualification is just dependent upon a minimum
prominence.
Dominance
is applied to hills whose prominence equal or exceed half that of their
absolute height.
For those that are not initiated
with the intricacies of hill list criteria the above explanation can sometimes be
a difficult concept to understand, but the essence being is that Prominence is
used as part of a criteria in conjunction with another criterion which is
usually Minimum Height, whereas Relative Height is normally used as a singular
criterion that is not dependent upon any form of minimum height except for that
stipulated for its relative height, whereas Dominance relies upon the
relationship between the hill’s prominence and its absolute height and is part
of a criteria in conjunction with another criterion which is Minimum Height.
The first use of what we now
refer to as Relative Height in a published hill list was by Eric Yeaman in his
‘Handbook of the Scottish Hills’ which was published in 1989 by Wafaida. However, the term Relative Height was coined
by Alan Dawson for the Marilyns which were first published in ‘The Relative
Hills of Britain’ book by Cicerone Press in 1992.
These two publications
dispensed with the concept of Prominence with Eric Yeaman using 100m of
Relative Height as the main part of his Scottish list and Alan Dawson using
150m for his British list.
The next link in this small
chain that takes in Prominence and Relative Height is Dominance, and therefore
Dominance can be viewed as the next step in the evolutionary process of Prominence.
Dominance is a new concept for
a published list to hills within Britain and to the knowledge of the author was
first used for hills within Britain in early 2009 under the working title of
‘The Ultra Prominent Summits of Wales’, this title was shortened to the UPPs
and was later changed to ‘The Dominant Hills of Wales.’ The change of name was instigated after a discussion
with Mark Trengove who pointed out that the same concept of Dominance had been
used by Eberhard Jurgalski in written format in 2001 and in published format in
2004, and as the 5,000ft prominence world peaks are known as the Ultras, their
title having been shortened from the Ultra Prominent Peaks, it was sensible not
to use a working title that was similar to another list that used different
criteria. Therefore, the title of Y
Trechol - The Dominant Hills of Wales became the norm and the term of Dominance
used to describe it, with the term Y Trechol being the Welsh for ‘The
Dominants.’
The concept of Dominance was
independently conceived by the author and was not copied from Eberhard as until
discussing the concept of this list with Mark Trengove, I had not heard of Eberhard
Jurgalski, but the term ‘Dominance’ follows Eberhard’s lead, as this is the
norm when dealing with terms such as Prominence and Relative Height, each in
turn were coined by someone and then they have become terms used by many.
To fulfil the qualification of
a hill being Dominant its prominence has to be first known. Therefore a Dominant list cannot be compiled
unless the Prominence of each hill is known beforehand, and for a country such
as Wales there are many hills that qualify under a stipulated minimum prominence
of 30m. I thought it wise to follow this
minimum prominence figure as this had been previously used in a number of
listings, these are briefly detailed below.
For Wales these 30m minimum prominence
based lists were first published over a period of 20 years from 1984–2004. These listings were reliant upon data
produced by Terry Marsh, Michael Dewey and Myrddyn Phillips. However, although all the lists produced by
these people specified a minimum drop of 30m none of them listed the actual
drop figure; this was added at a later date.
During this time listings to the majority of these hills were also
independently produced by E. D. ‘Clem’ Clements whose work appeared on the RHB
Yahoo Group database.
The theory of Dominance was
conceptualized shortly after all the drop values were added to my hand written
Master Lists and the 100m height bands expanded upward to include all P30
summits in Wales. This Dominance
criterion was conceptualized at approximately the same time as that of
Remoteness, with both taking form from the same question – ‘what else can be
considered once prominence values are given to all hills?’ Once this question was asked the theory of
Dominance sprung in to my mind and that of Remoteness soon followed.
The Remoteness list was later
published on Geoff Crowder’s v-g.me website in 2011, and updated and
co-authored with Aled Williams and published by Europeaklist, Haroldstreet and
Mapping Mountains in April 2015. But until
now the Dominance list has never been published.
Before detailing what Y Trechol
- The Dominant Hills of Wales list consists of it may be prudent to detail the
qualification for the main list:
Those P30 hills whose prominence
equal or exceed half that of their absolute height.
Also included is a list to the
Lesser Welsh Dominants, these are the additional P30 summits whose prominence
is between one third and half that of their absolute height.
The list consists of the
following:
Group: Each hill appears under their Group, this is
the group / range that the hill is a part of.
For example; Carnedd Llywelyn (SH 683 643) is part of the hill group
known as the Carneddau. The Groups are
arranged from north to south on a west to east orientation. The names of the Groups used in this list
have received extensive input from Aled Williams.
Name: This is considered the most appropriate name
for the hill with respect to the information available to the author. Sometimes the name used does not correspond
to current Ordnance Survey map spelling and composition or the name may not
appear on any map. Where no appropriate
name has been discovered for the hill from any source, the Point (for example;
Pt. 78m) notation is used rather than making up a name that has no local or
historical evidence of use. The Welsh
place-names that appear in this list and that were sourced from Ordnance Survey
mapping are reproduced as simple compositions, with hyphenated and compound
names reduced to the component elements.
It must be noted that this process will on occasion result in loss of
pronunciation information and as such, is not ideal. However, this protocol has been implemented
in order to simplify the composition due to the inappropriate and inconsistent
hyphen use that Ordnance Survey maps are prone to.
Dominance: This is the Dominance of the
hill’s height between bwlch and summit (its prominence) over that of its height
from sea level (Ordnance Datum Newlyn) to its bwlch. The Dominance is given as a percentage.
Region: There are three Regions in Wales;
North Wales, Mid and West Wales, and South Wales. The Regional split of Wales used in this list
has received extensive input from Aled Williams and will be detailed on the
Mapping Mountains blog at a later date.
Sub-Region: There are a number of
Sub-Regions in Wales and those used in this list have received extensive input from
Aled Williams and they will be detailed on the Mapping Mountains blog at a
later date.
1:50,000
Map: This column gives the number or numbers of
the 1:50,000 Ordnance Survey Landranger map that the summit of the hill appears
on.
1:25,000
Map: This column gives the number or numbers of
the 1:25,000 Ordnance Survey Explorer map that the summit of the hill appears
on.
Grid
Reference Summit: This is
the ten figure grid reference (10FGR) for the summit of the hill. This has either been produced by an accurate
survey, a map spot height or when neither is available by a centralised
position in an uppermost contour ring.
When the accurate survey has been conducted independent of the Ordnance
Survey a (S) for ‘survey’ will appear adjacent to the 10FGR, a (TP) if the
10FGR is taken to a ‘trig pillar’, a (B) if the 10FGR is taken to a ‘bolt’ or a
‘block’, a (L) if the 10FGR is taken to the position of a ‘levelled’ height on
old maps, a (HH) if the 10FGR is taken from a ‘hand-held’ GPS unit, a (SH) if
the 10FGR is taken to a ‘spot height’ either on current or old maps and an (I)
if the summit position has been ‘interpolated’ from contours.
Height
(m) Summit: This
gives the map height in metres of the hill above Ordnance Datum Newlyn (ODN),
often referred to as sea level. Where a
height is quoted to a decimal place it implies that the hill has been surveyed
by GPS / GNSS receiver (these heights may not match current Ordnance Survey map
heights). Where a ‘c’ (circa) appears
preceding the height it means there is no known spot height available and the
height has been estimated from contour interpolation.
Grid
Reference Bwlch: This is
the ten figure grid reference (10FGR) for the bwlch of the hill. This has either been produced by an accurate
survey, a map spot height or when neither is available by a centralised
position between converging hill to hill and valley to valley contours. When the accurate survey has been conducted
independent of the Ordnance Survey a (S) for ‘survey’ will appear adjacent to
the 10FGR, a (L) if the 10FGR is taken to the position of a ‘levelled’ height
on old maps, a (HH) if the 10FGR is taken from a ‘hand-held’ GPS unit, a (SH)
is the 10FGR is taken to a ‘spot height’ either on current or old maps and an
(I) if the bwlch position has been ‘interpolated’ from contours.
Drop
(m) Summit to Bwlch: This
column details the prominence of the hill; this is commonly referred to as
‘drop’ or ‘reascent’. The drop is the
height difference between the summit and connecting bwlch to the higher parent
peak along the watershed. The letter ‘c’
before the drop figure signifies there is no spot height or surveyed height
known for either summit or more usually, the bwlch, therefore a part of the
drop figure has been estimated from contour interpolation.
Drop
(m) – Bwlch to ODN: This
gives the map height in metres of the bwlch above Ordnance Datum Newlyn (ODN),
often referred to as sea level. Where a
height is quoted to a decimal place it implies that the bwlch has been surveyed
by GPS / GNSS receiver (these heights may not match current Ordnance Survey map
heights). Where a ‘c’ (circa) appears
preceding the height it means there is no known spot height available and the
height has been estimated from contour interpolation.
Notes: This column gives details relevant to the
hill.
With special thanks to Aled
Williams and Mark Trengove for their continued support and to Eberhard Jurgalski for
taking Dominance to the masses. Thanks
are also due to the people who submit 10 figure grid references to the Database
of British and Irish Hills (DoBIH) and for DoBIH making these available for
public use.
This list will appear in biweekly or monthly instalments with the first Group listed being Ynys Môn. The Dominant Hills of the Carneddau will appear on the 17th December 2015.
To
access Y Trechol - The Dominant Hills of Wales list please click {here}
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