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The ADL Gazetteer Protocol

The ADL Gazetteer Protocol. Greg Janée gjanee@alexandria.ucsb.edu. Goals. Capture the essence of... what a gazetteer is what a gazetteer does Balance client needs vs . server burden clients want functionality, uniformity, completeness servers want minimal requirements, overhead

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The ADL Gazetteer Protocol

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  1. The ADL Gazetteer Protocol Greg Janée gjanee@alexandria.ucsb.edu

  2. Goals • Capture the essence of... • what a gazetteer is • what a gazetteer does • Balance client needs vs. server burden • clients want functionality, uniformity, completeness • servers want minimal requirements, overhead • “non-preclusive simplicity” wins • Accommodate differing implementations • semantics deliberately underspecified

  3. Abstract gazetteer model • Gazetteer = gazetteer entries + relationships • Gazetteer entry • describes a single place • one entry per place • Inter-entry relationships • Sacramento is the “capital of” California • some spatial relationships are implicit

  4. Gazetteer entry • Identifier • Attributes • 1+ names • unqualified, e.g., “San Diego” • 1+ footprints • region defined in WGS84 coordinates • not necessarily contiguous • 0+ classes • term drawn from vocabulary or thesaurus • city, park, mountain, lake, etc. • Attribute qualifiers • primary • historical

  5. Services Stateless, independent, synchronous functions • get-capabilities() capabilities description • which protocol features are supported • query(query)  reports • returns all entries that match a query • download()  reports • downloads entire gazetteer • add-entry(report)  identifier • relate-entries(relationship, identifier1, identifier2) • remove-entry(identifier)

  6. Query language • Five fundamental constraint types... • identifier • find gazetteer entry #314159 • name • find “San Diego” • footprint • find places that overlap a given region • class • find cemeteries • relationship • find the capital of California • …and boolean combinations thereof

  7. Protocol technology • XML • XML schemas, XML namespaces, XML linking • OpenGIS Geography Markup Language (GML) • HTTP • [SOAP] • [WSDL]

  8. Future directions/outstanding issues • Seeking broad deployment • still short of Frew’s “rule of three” • Qualification of names • “Santa Barbara, CA” • Relationships • codify specific relationships? • relationship types? • topological, role, ... • Extensions • if and how to enrichen gazetteer model • federation of gazetteers

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