The earth is three dimension object while our screen is two-dimension.
So when we use the gis software to display the geographic data, how do they handle the translation between latitude/longitude and screen pixels?
I know the projection which will translate the latitude/longitude to a two-dimension point. But what is the unit of the two-dimension point? Is it the 'pixel`?
Update:
To make this question clearer:
The rectangle is the screen view port(with size 800x600), and I know the center coordinate(65E,26N), then how to get the coordinate of the four corner?