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Simple Dublin core elements:
Geo-referencing and Dublin Core
Dublin Core has several methods of geo-referencing locations. The fully qualified tag is DC.coverage.spatial, and at least two different data formats, with several flavors apiece.
http://dublincore.org/documents/dcmi-point/ describes the DCMIPOINT data format, and http://dublincore.org/documents/2000/07/28/dcmi-dcsv/ describes how to encode it as a single string. There also appear to be references to a format labeled WGS84-DDM: http://www.ecai.org/documentation/ecai_metadata_standard.html, which is the WGS-84 datum expressed in decimal degrees and meters.
The Getty Thesaurus of Geographic Names (TGN: http://www.getty.edu/research/tools/vocabulary/tgn/) is one method, and another is a combination of coordinates and names (DCMIPOINT).
TGN Be careful, since most of the documentation for georeferencing with DC is too vague on the precise format, and most of the examples are incorrect.
Through corresponding with the Getty staff, I have determined this appears to be the correct referencing scheme:
<link rel="schema.DC" href="http://purl.org/dc/terms/" title="DCMES plus DCMI recommended qualifiers" /> <meta name="DC.Coverage.spatial" scheme="TGN" content="7014456" /> <meta name="DC.Coverage.spatial" scheme="TGN" content="name=San Francisco (San Francisco county, California, United States)" /> <meta name="DC.Coverage.spatial" scheme="DCMIPOINT" content="name=San Francisco, CA, U.S.A.; east=237.5833; north=37.7667" />
In this example, the numeric TGN value is a unique database ID for the San Francisco entry in the TGN database. The line below it is the proper way to point to that database entry with plain text. The Web link to that entry is currently http://vocab.pub.getty.edu/cgi-bin/tgn_browser/tgn.spl?key=7014456&searchtype=record&file=/tgn_browser/index.html
TGN references of the form San Francisco (preferred, C,V,N) are not unique, and are thus not appropriate to use as a reference. This form is simply a description of the place, indicating that San Francisco is the preferred name, it is the Current name, it in the Vernacular (local) language, and that it is a Noun.