There are standards for the digital encoding of coordinates and other
related essential information (e.g., coordinate systems, datums,
spheroids). Two places to start:
One of the major bodies dealing with the establishment of such standards
is the Open Geospatial Consortium ( http://www.opengeospatial.org/ ),
which publishes relevant specifications.
One also might care to look at the work of the Alexandria Digital
Library Gazetteer project, whose gazetteer protocol includes
specifications for the encoding of coordinates (
http://www.alexandria.ucsb.edu/gazetteer/ ).
