The first list to the Welsh
200m P30 hills was published on Geoff Crowder’s website v-g.me in 2000; this
list preceded the list of TuMPs by nine years, the list proved a very useful
resource for the TuMP compilation for this category of hill.
The Welsh 200m P30 list
documents all hills in Wales that are at or above 200m in height and are below
300m in height, to qualify for the main list each hill requires a minimum of
30m of prominence.
The hills listed below are
updates to the Welsh 200m P30 list originally published on Geoff Crowder's
website. To see the original list click {here}
The original published list had
a Sub-List which was entitled ‘Hills to Survey’. This list consisted of all hills in Wales in
the stipulated height band that have a minimum of 20m of prominence, but do not
meet the minimum 30m of prominence to enter the main list, according to
Ordnance Survey map spot heights and contours.
Nowadays the standard Sub-List takes in all hills that have a minimum of
20m of prominence. However, the Hills to
Survey Sub-List discounted hills whose map spot heights gave a drop value of
less than 30m, but more than 20m. By
doing so, the only hills that were Sub-Listed were those that map values
dictated stood a chance of entering the main list, for example; if a hill had a
summit spot height of 250m and a bwlch spot height of 221m, it was not listed
in the Hills to Survey Sub-List as with 29m of drop I thought it did not stand
a chance of main list qualification.
When compiling the Sub-List I
was measuring many hills for P30 status using a basic levelling technique,
please click {here} for more information concerning this. I now know that Ordnance Survey spot heights
have a standard margin of uncertainty of + / - 3m associated with their
accuracy. Therefore many hills that were
not listed in the original Sub-List may have sufficient drop to enter the main
list. Because of this the Sub-List has
been altered to include all hills that have a minimum of 20m of drop but are
not known to attain the minimum 30m of drop to enter the main list.
The hills listed below are
those major amendments to the original Welsh 200m P30 list as it appears on
Geoff’s website. There are many hills
that have been promoted from the Hills to Survey Sub-List to the main list,
whilst there are many additions to the Sub-List now that it has been standardised
to include all 20m minimum but below 30m drop hills.
When the 200m P30 list was
first published it was the first to this category of hills and in some way it
and its other 100m height band lists paved the way for Clem’s data that later
appeared on the RHB file database and then for the TuMPs listing by Mark
Jackson.
As well as the first P30 list
to this height band the list is now the first to include a comprehensive
Sub-List.
TuMP baggers beware; as the
main list also includes P30’s not listed by Mark Jackson, so if you want to
visit all P30’s you’ll have to include some non TuMPs to do so.
The list will be updated on a
weekly basis and will be done so through each Group category, starting from the
north and working south. The Thirtieth
Group is Bannau Brycheiniog.
Bannau
Brycheiniog
West and then north from SO 242
154 following the River Clydach to bwlch at SO 192 115, and bwlch at SO 174
115, and bwlch at SO 147 115, and bwlch at SO 119 101, and bwlch at SO 082 086 towards
the Nant Moriais to SO 046 062, continuing east of the Taf Fawr to the Llwyn-on
Reservoir at SO 012 114 and from SO 004 128 to the Cantref Reservoir at SN 996
153 and from SN 992 163 to the Beacons Reservoir at SN 989 183 and the Blaen
Taf Fawr from SN 986 190 to SN 987 194 and stream to bwlch at SN 982 203 and
the Afon Tarell to SO 038 288, continuing south of the Afon Wysg (River Usk) to
SO 242 154. Bordering with Y Mynyddoedd
Duon and Mynydd Epynt to the north, Fforest Fawr to the west, Bryniau Cymoedd
to the south and Y Mynyddoedd Duon to the east.
Twmpau - 200m updates
Cefn
Cantref 293m SO 048 269
This hill has been promoted
from the Sub-List as the given drop is 30m, based on the hill having a twin
293m summit and a 263m spot height at the bwlch, with the latter appearing on
the Ordnance Survey enlarged Geograph map.
The summit at SO 048 269 has a triangulation pillar on it with a flush
bracket height of 293.223m, meaning ground at the immediate base of the trig is
likely to be just under 293m high, but as ground adjacent to the base of the
trig looks slightly higher the hill retains its twin summit status, for
now! The other summit is positioned at
SO 049 262.
Next update due on the 10th November 2014
No comments:
Post a Comment