view_map_rgb takes a bigmap and renders it based on illumination and viewing geometry.
A single bigmap is required
It creates view.ppm, that is a red/blue stereo pair image.
Asks for maplet name [6 char].
Then asks for sun position as a vector in x,y,z coordinates from center of map (i.e. South, East, Height), and then the viewing slant angle.
For sun angle, 0 0 1 should be noon, while 0 1 1 should put the sun directly east at a 45 degree angle.