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The ADL Testbed. Greg Janée gjanee@alexandria.ucsb.edu. Outline. ADL: an architecture for georeferenced digital libraries a digital library Library contents ADL architecture; ramifications for interoperability Status Recent usage Summary. Library contents — qualitative summary.
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The ADL Testbed Greg Janée gjanee@alexandria.ucsb.edu
Outline • ADL: • an architecture for georeferenced digital libraries • a digital library • Library contents • ADL architecture; ramifications for interoperability • Status • Recent usage • Summary
Library contents— qualitative summary • Catalog • georeferenced items: aerial photographs, scanned & paper maps, GIS layers, scientific datasets, text documents, videos, etc. • FGDC, USMARC, and many other types of metadata • Gazetteer • place & feature names, earthquake epicenters, county boundaries, USGS quadrangle names, etc. • ADL Gazetteer Content Standard metadata • GeoRef • bibliographic records • USMARC metadata • Z39.50 gateway • BIB-1 or GEO attribute sets
Library contents— quantitative summary • Series Number Size (GB)Geodex 335,000 0Landsat 1,200,000 56DOQQ 12,000 684DRG 1:24,000 3,000 52DRG 1:100,000 ? 2.6NASA/Ames 430,000 0Aerial photos 25,000 344SPOT 200 5.9DEM 3,000 ?NIMA Geonames 5,600,000 0GNIS 300,000 0TOTAL 7,908,200 1,144.5
uniform client services middleware collection server API ADL architecture JIGI Web interface GeoWorlds Catalog Z39.50 Gazetteer GeoRef
Abstract, searchable indexes Similar to other “umbrella” metadata schemes such as GILS and Dublin Core, except search buckets are: optimized for retrieval, as opposed to description optimized for geospatial data and geospatial searching Searchable collection metadata is mapped to buckets Users phrase queries in terms of bucket constraints (only) Geographic locations Dates Types Formats Originators Assigned terms Topical text Identifiers ADL architecture: search buckets
ADL architecture: metadata • Flow of metadata and metadata semantics: • Collection metadata is mapped to search buckets • metadata semantics are lost • Metadata is also mapped to ADL’s standard metadata reports • XML DTDs for the most part describe syntactic structure only, so again, metadata semantics are lost • Conclusion: ADL’s bucket system works well, but it makes interoperability in larger contexts difficult • Conjecture: should interoperability be transitive?
Status • The ADL library will become an operational component of the California Digital Library in January 2000 • currently rewriting software to increase reliability, performance, portability, etc. • reloading all collections • Research will continue under the Alexandria Digital Earth Prototype (ADEPT) and InterLib projects • emphasis on intelligently using library holdings • library will contain both data and programs (e.g., geophysical models) • system will be used in educational settings • We are interested in exploring how ADL (particularly, the gazetteer) can be used as a service
Recent usage • Internal • preliminary analysis of user/usage correlation was presented at the ASIS mid-year meeting • continued informal usage by UCSB’s Map & Imagery Laboratory to help service its customers • External • Goodchild and Zhou, “Finding Geographic Information: Collection-Level Metadata,” will appear in Geoinformatica • an analysis of the role and value of collection-level metadata in finding appropriate collections to search • relied on the spatio-temporal characterization of collections that ADL provides • anticipating significant usage under CDL
Summary • ADL: both an architecture and a library • Close to becoming an operational component of CDL • anticipating significant usage • Future research will focus on use of the library, particularly in educational settings • Conjecture: should interoperability be transitive? • For more information: • Website: http://www.alexandria.ucsb.edu/ • Email: gjanee@alexandria.ucsb.edu