Hill Lists –
Cymru / Wales
Y Trechol -
The Dominant Hills of Wales
Introduction
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 ascertained from LIDAR data, a (LV) 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) or it has been ascertained by the analysis of LIDAR data.
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. Where an * appears
against the height of the hill it means that this height has been converted to
OSGM15.
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 ascertained from LIDAR data, a (LV) 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. Where an *
appears against the drop value of the hill it means that this figure has been
ascertained from the conversion of the summit and bwlch height to OSGM15.
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) or it has been ascertained by the analysis
of LIDAR data. 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. Where an *
appears against the height of the bwlch it means that this height has been
converted to OSGM15.
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 monthly, bi-monthly or quarterly instalments with the twenty third
group being Hirddywel. The Dominant Hills of Elfael will appear on the
3rd November 2017.
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