#1 Patch to add Equidistant Cylindrical Projection

[Rick Richardson]

#
# Equidistant Cylindrical Projection
#
# It was credited to Erathostenes (ca. 200 b.c.)
and to Marinus of Tyre
# (ca. 100). Its trivial construction made it
widely used, even for
# navigation, until the Modern Age.
#
# Simple, fast projection that is good enough for
street level road maps
#
# The map scale will be approximately equal in
X/Y directions, given a
# small enough area.

Here is a very simple projection from lat/lon that can
be used for maps on the scale of street/city level road
maps. You feed it the lat/lon of the desired point, as
well as the lat/lon of the center of the map.

It will give approximately equal distances in the X/Y
directions at those scales. So maps at those scales
won't look "squashed". In my area (N45.0, W93.5) it'll
be off by 2-3 meters at each of the corners of a map
that is showing a 2000m x 2000m area.

There's probably some easy ways to integerize it that
will make it hideously fast.

[Rick Richardson]