[Proj] Graduated equidistant projections for convenient
mikeo2106 at msn.com
Tue Jul 31 14:23:10 EDT 2007
Sorry to post so much, but this completes what I have to say, and so I won't
keep on making a nuisance of myself :-) I've noticed that I left something
out of my previous posting:
I forgot to add that I realize that the sinusoidal projection gives a
combination of easy position-measurement and equal area. (Bonne and
Stabius-Werner are much more inconvenient, due to their curved parallels and
Though the sinusoidal s curved meridians make longitude measurement not
quite as easy as it is with a cylindrical projection, its still easy.
Though, for me, the locations of a data maps zone boundaries are the maps
only important information, and the whole point of the map, I understand
that many people are also interested in global comparisons and the relative
areas of zones. The sinusoidal suits both purposes.
The sinusoidals scale variation and departures from conformality arent so
bad when the map is interrupted.
If an uninterrupted world map is desired, with easy position-measurement,
less distortion than the uninterrupted sinusoidal, and reasonably equal
area, Id suggest the equidistant elliptical projection. When Mollweide has
a 30 degree graticule, the spacing of its parallels is only a little
non-uniform. That suggests that the equidistant elliptical wouldnt have
enough area inaccuracy to bother anyone. Among the uninterrupted world maps,
an elliptical projection with straight parallels, in my opinion, gives the
most realistic-looking and attractive overall portrayal of the Earth.
The price of an uninterrupted, reasonable-areas world map is that it isnt
much good for distances, directions and shapes. Its attractive, but the
interrupted sinusoidal, the graduated equidistant cylindrical, and the
Mercator are more useful.
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