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 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 (Corcogemore) becomes the first 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 we 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.
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.