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 Twenty Seventh
Group is Penlle’ rcastell.
Penlle’
rcastell
North and then east from
SS 620 907 following the Clyne River to bwlch at SS 595 939 and the Gors Fawr
Brook to SS 592 967, continuing north of the Afon Llan to the sea at SS 560
979, continuing east of the Afon Llwchwr (River Loughor) to SN 622 105,
continuing south of the Afon Aman to SN 686 133, continuing west of the Garnant
to bwlch at SN 698 094 and the Upper Clydach River to SN 723 036, continuing
west of the Afon Tawe to the sea at SS 666 917.
Bordering with the Gŵyr and Mynydd Sylen to the west, Y Mynydd
Du to the north, Bryniau Cymoedd to the east and the sea to the south.
Sub-Twmpau - 200m updates
Pt.
299m 299m SN 696 058
This hill is a new entry in to
the Welsh 200m P30 Sub-List, however its entry is contentious as Ordnance
Survey mapping suggests this hill exists due to spoil heaps from old
mining. To include a hill in a list
because its existence is due to man’s recent incursion is difficult, but as
current Ordnance Survey maps give this hill continuous contour lines it
suggests that the hill is permanent in nature and as it exists it would be
difficult to not include it. Subjectivity
would also have to be taken in to account as to be considered permanent in
nature the hill would ideally need to be landscaped and not comprise just spoil
waste. The Ordnance Survey enlarged
Geograph map gives this hill a 299m summit spot height, and bwlch contouring is
between c 270m – c 280m and the bwlch has been estimated as being c 275m high,
these values give the hill c 24m of drop.
Next update due on the 20th October 2014
No comments:
Post a Comment