[mapserver-users] project onto a globe?

[Ed McNierney]

Tom -

If I understand correctly, what you folks in the UK call a "2D representation of a globe" is known as a "circle" over here <g>.

Is that right?  There are certainly map projections available that project the surface of the entire Earth onto a circle, such as the Azimuthal Equidistant.  However, they of necessity introduce gross distortions at the edges (away from the center point of the projection).  This is also true of projections like Mercator and your example map, but those projections are common enough that they "look normal" to most people.

You can see a good example of the Azimuthal Equidistant used to map the whole Earth (centered on North America) at:

http://www-ccs.ucsd.edu/gmt/doc/html/GMT_Docs/node86.html

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242 

-----Original Message-----
From: Tom Hodder [mailto:t.hodder at globalgold.co.uk]
Sent: Tuesday, November 26, 2002 12:43 PM
To: mapserver-users at lists.gis.umn.edu
Subject: RE: [mapserver-users] project onto a globe?



>
> Tom -
>
> I don't think I understand the question.  Monitors and printers
> are flat (relatively) surfaces - so most map projections project
> a portion (or all) of the earth onto a flat surface.  What
> exactly are you trying to do?
>
> 	- Ed
> >

sorry, i meant a 2d representation of a globe.

I have it setup where its possible to zoom out to a world basemap, so I
showed it
to a marketing bod, it looks similar to this;
http://mapserver.socialchange.net.au/cgi-bin/mapserv?map=..%2Fmaps%2Fworld%2
Fworld.map&layer=land_raster&zoomsize=2
(but this is not my version, as I'm developing it on an internal server)

and they said can make it so that the complete map is projected onto a 2d
globe
centered about a given point, because that looks nicer. so i said I will see
what
I can do.

Cheers

Tom H