Calf Top has been re-classified
to a Hewitt based on the conversion of data from OSGM15, which is the Ordnance
Surveys latest geoid model.
Alan Dawson announced the
findings on the RHB Yahoo Group forum on 30.08.16 and announced his acceptance
of Calf Top as a new Hewitt via a number of news outlets, including the Mail
and the Express online.
Calf Top (SD 664 856) now a 2,000ft mountain and a new Hewitt |
The reclassification of Calf
Top to Hewitt status was based on two surveys conducted six years ago using precision
levelling and GPS equipment by John Barnard, Graham Jackson and Myrddyn
Phillips. On the first visit a two hour
data set was gathered, and on the second visit four hours of data were gathered,
each data set was sent to Ordnance Survey.
The result when Ordnance Survey processed the data through Bernese
software was 609.58m, just 2cm below 609.6, or in imperial terms, less than one
inch below 2,000ft.
The new geoid model (OSGM15)
produced by Ordnance Survey have increased known heights in both England and in
Wales by around 2 – 4cm, meaning that Calf Top nudges past the 609.6m / 2,000ft
benchmark height by 6mm.
The news that Calf Top is a new
2,000ft mountain has been reported on various websites, and in a number of
national newspapers, including:
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