How to draw a global day night curve
- by Lumis
I see many applications which have world-clock map, and I would like to make my own to enhance some of my mobile apps. I wonder if anybody has any knowledge where to start, how to draw a curved shadow representing the dawn and the sunset on the globe. See the example:
http://aa.usno.navy.mil/imagery/earth/map?year=2012&month=6&day=19&hour=14&minute=47
I think that this curve goes up and down and creates an artic day/night etc
Perhaps there is some acceptable approximation formula without a need to load data for each our and each global parallel and meridian...