On Fri, Jan 8, 2010 at 8:32 PM, John Smith <deltafoxtrot...@gmail.com>wrote:
> 2010/1/9 Martin Siegel <martin.sie...@sdas.de>: > > AFAIK this is not correct. First of all the PoV of Mercator projection > > is not going through the center of the earth. It's a somehow stretched > > cylindrical projection and it goes through the north-south-axis. > > The way it is stretched causes that angles on the earth are the same as > > on the map. I'm not completely sure, but I believe the only straight > > lines that correlate between earth's surface and Mercator projected maps > > are the equator and all great circles parallel to the meridians. > > Not quite, it's about 45 degrees north/south is in correct > proportions, everything else gets stretched. > He is indeed correct that the only line of latitude which is "straight" (as in, a geodesic) is the equator, and that all the lines of longitude (meridians) are "straight". Sort of. This assumes the earth is a sphere. Of course it isn't.
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