[Gdal-dev] Projected vs Geographic Coordinate Systems

[Simon Perkins]

Quick question: is it fair to say that most if not all georeferenced 
raster images that one typically comes across use a projected (rather 
than geographic) coordinate system?

Do typical GIS packages handle rasters with geographic (latitude / 
longitude) coordinate systems? And what do they do when displaying 
rasters in a projected coordinate system together with, say, vector 
layers in a geographic coordinate system? Is it usual to convert the 
vector layer to the projected coordinates or vice versa?

Just wondering if I can get away with avoiding having to handle 
geographic coordinate systems in my (mostly raster focused) application 
for the time being... Any advice much appreciated!

Cheers,

Simon