Cock Hill (ST 153 750)
There has been a Summit Relocation to a hill that
is listed in the 100m Twmpau and Y Trechol – The Dominant Hills of Wales,
with the summit height, bwlch height and their locations, the drop and status
of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.
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| LIDAR image of Cock Hill (ST 153 750) |
The criteria for the two listings that this summit
relocation applies to are:
100m Twmpau - Welsh hills at or above 100m and below 200m in height with 30m
minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau with the criteria for this sub category being all
Welsh hills at or above 100m and below 200m in height with 20m or more and
below 30m of drop, with the word Twmpau
being an acronym standing for thirty
welsh metre prominences and upward.
Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose
prominence equal or exceed half that of their absolute height. With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose
prominence is between one third and half that of their absolute height. The list is authored by Myrddyn Phillips with
the Introduction to the start of the Mapping Mountains publication of this list
appearing on the 3rd December 2015.
The name of the hill is Cock Hill and it is adjoined
to the Bro Morgannwg group of hills, which are situated in the southern part of
South Wales (Region C, Sub-Region C2), and it has the A4232 road to its
north and east and a minor road towards its south, and has the city of Caerdydd
(Cardiff) towards the north-east.
When the original Welsh 100m P30 list was
published on Geoff Crowder’s v-g.me website this hill was listed with a c 115m summit
height positioned at ST 153 750, based on the uppermost ring contour that
appears on contemporary Ordnance Survey 1:25,000 Explorer maps which takes in a
triangulation pillar with an adjoining flush bracket height of 115.345m
positioned at ST 15338 75022.
 |
| Extract from the Ordnance Survey 1:25,000 Explorer map |
The details for this hill were re-evaluated when
the Ordnance Survey Vector Map Local hosted on the Geograph website and which
is entitled the Interactive Coverage Map became available online, and as this
map gives no further details the summit location remained the same.
However, it was not until LIDAR became available
that the details for this hill could be accurately re-assessed. The LIDAR (Light Detection & Ranging)
technique produced highly accurate height data that is now freely available for
much of England and Wales.
 |
| LIDAR summit image of Cock Hill |
The summit height produced by LIDAR analysis is 115.6m
positioned at ST 15303 75089 with LIDAR also giving a 115.7m height positioned
at ST 15310 75062 to a raised field boundary that is excluded from the height
of this hill as it is considered a recent man-made construct and with the
natural summit of the hill positioned in a different field compared to where
the summit was originally listed. The
above detail comes
within the parameters of the Summit Relocations used within this page heading,
these parameters are:
The term Summit Relocations applies to any listed
hill whose summit meets the following criteria; where there are a number of
potential summit positions within close proximity and the highest point is not
where previously given, or a relocation of approximately 100 metres or more in
distance from either the position of a map spot height or from where the summit
of the hill was previously thought to exist, or when the summit of the hill is
in a different field compared to where previously given, or when the natural
and intact summit of a hill is confirmed compared to a higher point such as a
raised field boundary that is judged to be a relatively recent man-made
construct.
Therefore, the summit height produced by LIDAR
analysis is 115.6m to ground meeting the criteria used within this list and
this is positioned at ST 15303 75089, this is in a different field to the
previously listed summit position and is approximately 80 metres north-westward
from it and approximately 28 metres from where the highest part of the raised
field boundary is situated, and as the
latter is considered a relatively recent man-made construct it is not taken as
a part of the height of this hill.
The full details for the hill are:
Group: Bro Morgannwg
Name: Cock Hill
OS 1:50,000 map: 171
Summit Height: 115.6m
(LIDAR, natural summit)
Summit Grid Reference (new position): ST 15303 75089 (LIDAR, natural summit)
Bwlch Height: 46.3m
(LIDAR)
Bwlch Grid Reference:
ST 13392 74714 (LIDAR)
Drop: 69.3m (LIDAR)
Dominance: 59.92%
(LIDAR)
Myrddyn Phillips (September 2019)
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