----------------------------Original message---------------------------- In analytical cartography one uses projections to solve problems in the computer without ever seeing the map. In fact several projections may be used sequentilly(sequentally) in this process. After finishing the result can be put onto the screen in an orthographic view (if less than a hemishphere). If it's a small area and you wish to use a sceeen cursor to point at something and retrieve its Lat/lon use Tobler's quick and simple local projection (Am Cartographer Vol 1).