From: Kevin Ward <kablukiw@gm...> - 2010-05-27 22:07:50
I am trying to come up with a solution for the following and have been
racking my brains for a while and haven't come up with anything:
Given: a cylindrical equidistant global image (WGS84)
Desired output: a cylindrical image of the same dimensions, only
tilted "forward" to account for Earth's axial tilt. So, if the
original image is 360x180 and the north pole is at 180,0 then the
output image is still 360x180 but the north pole is at 180,23 (for a
23.44 degree tilt).
The usage is this: If I have a spherical display and project the
original image on it, the north pole is at the top. I want to be able
to create cylindrical images that have the axial tilt built into the
image so that I don't have to rely upon capabilities of the display
unit to account for that.
When I was first presented with this I thought it should be simple,
but now I'm not so sure, or maybe I've skipped over the simple
Any hints would be greatly appreciated,
From: Michael Bedward <michael.bedward@gm...> - 2010-05-29 08:31:36
I wish I had the simple solution for you - it's such a cool question :-)
I *think* one approach is to convert lat long values to spherical
coordinates (a bit of googling will find formulae for this), apply the
tilt to the spherical positions and then convert back to pseudo
lat-longs which can be plotted.
If you take it further I'd love to hear how you get on.