In message <e1xj1zw-0004rj...@mta1.cl.cam.ac.uk>
Frank King <frank.k...@cl.cam.ac.uk> wrote:
> Dear Tony,
>
> What a fun thread you have spawned!
>
> Mercator is possibly the most famous
> Belgian, not that Belgium existed in
> his day but let's overlook that detail.
>
> The mathematics of Mercator's projection
> is quite challenging. Certainly Mercator
> himself didn't understand it!
>
> The first proper analysis was by Edward
> Wright who was a Fellow of Gonville and
> Caius College Cambridge in the days when
> there were 67 sundials in Caius Court.
> They are now down to their last six.
>
> To be sure the projection distorts sizes
> so Greenland appears about the same size
> as Africa but the UK is pretty small and
> the distortion is minimal. I do not
> understand Linda's map! As John Foad
> didn't quite say, this is decidedly an
> Alex Salmond projection.
>
> I'd use Mercator's projection for your
> project if possible. After all, that's
> what the Ordnance Survey use, albeit
> they turn the projection through a
> right-angle (the "equator" runs north
> to south).
>
> Peters's projection is really (in my
> view) the Gall Orthographic (Peters
> was over 100 years after Gall). It
> has no special advantages for a region
> the size of the U.K.
>
> I hope you find a proper map soon!
>
> Frank
>
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>
As Frank King mentioned, the subject of map 'projections' can be
a tricky one - and most of us probably think of "school atlas"
maps, where it is likely to be one based on "conical with two
standard parallels", where (as Tony Moss said), Latitude lines
will be slightly curved, and Longitude converging to the North.
However, Tony definitely wants 'orthogonal' (i.e. straight and
at right-angles) lines of Latitude and Longitude - which rather
restricts the projections you can use, though Tony did not give
his reasons WHY the map had to have these specific properties.
Strictly speaking, the UK Ordnance Survey 'National Grid' is
not based on a "Transverse Mercator" projection (as Frank King
suggested) - but here are two websites, with more information.
http://en.wikipedia.org/wiki/Map_projection
http://en.wikipedia.org/wiki/Ordnance_Survey_National_Grid
I hope they might be useful, and not even more confusing!
Sincerely,
Keith Christian.
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