Global get_vert_intersects (geosurf *gs, float *bgn, float *end, float *dir)
For consistancy, need to decide how last row & last column are displayed - would it look funny to always draw last row/col with finer resolution if necessary, or would it be better to only show full rows/cols?
scale used to calculate len of arrow still needs work needs go function that returns center / eye distance gsd_get_los function is not working correctly ??
generalize this concept to allow transform functions which are dependent on surfaces that are dependent on other surfaces, etc., as long as the dependency doesn't loop back.
Display commands (*.d) are captured and processed separately by mapdisp.py. Display commands are rendered in map display widget that currently has the focus (as indicted by mdidx).