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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).