I'm using/learning geodjango + postgis, and I'm trying to calculate distance between 2 cities in Poland. First using WGS84/4326 I define 2 points, and then after transforming this points into spherical mercator 900913 i get distance which is about 40km too long. Which map projection should I use then? Where can I find proper srid's for different countries?
sorry for the delay, 2 cities (lat; long): Slupsk(54.465249;17.026062) and Koszalin(54.193378;16.179428)