UKHillwalking
Article
The UKHillwalking website
recently published an article on the reclassification of Corcóg (Corcogemore) to Hewitt status. The original article and a link
to it on the UKHillwalking website appear below.
Ireland
Gains a 2000-ft Hewitt
Myrddyn
Phillips 21st July
Following a recent survey, an Irish hill has been
found to be over 2000 feet (609.6m) in height, gaining it promotion to the list
of Hewitts (an acronym for Hill in England,
Wales or Ireland over Two Thousand feet high).
Situated in the
Maumturk Mountains of Connemara, Corcóg (Corcogemore) is found at grid reference is L 952
491, and it appears on map 45 of the Ordnance Survey Ireland (OSI) 1:50,000
Discovery series.
The OSI map gives its
height as 609m, a smidgen under the benchmark height of 2,000ft (609.6m). This height was obtained through
photogrammetry which has a margin of uncertainty of approximately +/- 3m.
Its new height, on the
other hand, has been surveyed by the company Bluesky as 611.1m. For Ireland Bluesky have created a national
dataset based on photogrammetric survey using Vexcel cameras, creating a 1m DSM
and 5m DTM product. The accuracy given
for these is +/- 0.50m for the DSM with directly recorded points with no
interpolation, and +/- 1m for the DTM with some interpolation.
Earlier
this year this company was awarded the contract by Natural Resources Wales on
behalf of the Welsh Government to re-survey the whole of Wales using LIDAR
capturing the data at two points per metre resolution.
 |
| Corcóg's new height of 611.1m puts it into the Hewitts list. © EastWest Mapping |
Corcóg (Corcogemore) becomes
the latest Irish Hewitt to be promoted based on its height since the list was originally
published by TACit Press in September 1997. Its author and compiler was E D ‘Clem’
Clements, with the criteria being any Irish hill at or above 2000ft (609.6m) in height with 30m
minimum drop.
Since
Clem’s death the co-custodian responsibilities for the Irish Hewitts list have
passed to David Purchase and myself, and both are both in agreement with this
hill’s change of status based on the Bluesky survey. This reclassification also affects the list
to the 500-Metre Tops of Ireland co-authored and compiled by Michael Dewey and myself,
and Michael has been consulted and is also in agreement with this hill’s
reclassification.
 |
| Myrddyn Phillips and E D 'Clem' Clements |
Thanks
to:
Kieron
Gribbon of The Ireland Walking Guide website who raised the potential of this
hill being a new Irish Hewitt based on the 611m summit spot height that appears
on the Connemara Mountains map recently published by EastWest Mapping.
Barry
Dalby at EastWest Mapping for confirmation of the source of their height data,
and relevant details giving accurate height and co-ordinates.
Robert
Loughran at Bluesky for detailed analysis of their surveying technique,
including accurate heights and contours.
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