Posted on 2002-03-20
Can anyone provide me with an example of an algorithm to do the following conversion:
Latitude / longitude coordinate on earth's surface
Zoom level (from full world to a few miles across)
X/Y pixel width of PC screen
Asusming this lat/lon point on earth is being viewed form a point in space perfectly Normal to the earth's suface:
The X/Y point on the screen that the given input Lat/lon point maps to, given the above input data for zoom level and screen resolution.
I would also need a way to detremine if the lat/lon point is on the visible or hidden half of the earth (this is easy), and if hidden, figure out the last visible x/y point on the path from the previous visible point to the hidden point (more difficult).
Basically looking to map the spherical coordinates to rectangular coordinates.