stratford

Architectural DirectionsforDistributed Geolibraries: 

Architectural Directions for Distributed Geolibraries Greg Janée gjanee@alexandria.ucsb.edu

Outline: 

Outline Vision & goals Architecture: foundation CRADDL FEDORA Architecture: additions Standard thesaurus interface Two standard metadata models Core index/search service Tile-based browse/aggregation service Collection discovery service Gazetteer service Goals, revisited

Vision: 

Vision Fundamental organization of information Self-contained, georeferenced digital objects... ...aggregated into collections... ...networked into libraries The Library constitutes a “Digital Earth” Static and dynamic content Personal, customizable collections Collaborative use of distributed resources Component-based approach Specify interfaces and protocols Build representative services

Goals: 

Goals Find Find appropriate collections Find items within collections Using simplified, uniform methods Using more refined, perhaps collection-specific methods Assemble, structure, publish Create and populate new collections Structure collections using domain-specific thesauri Make available to others Use Invoke operations on items Integrate library into user application environment

CRADDL: 

CRADDL D-Lib Magazine, Nov. 1998

FEDORA: 

FEDORA apologies to Christophe Blanchi

Architecture: additions: 

Architecture: additions Standard thesaurus interface Two standard metadata models ADL-Basic: supports uniform description & search ADL-Full: supports XML-based querying on entire metadata Standard index/search services Core index/search service Tile-based browse/aggregation service Collection metadata Characterizes collection Supports collection discovery Gazetteer service

Standard thesaurus interface: 

Standard thesaurus interface

ADL-Basic fields & subfields: 

ADL-Basic fields & subfields Originator Subject-related text Title Assigned terms Type Format Spatial domain Date Time period of content Identifier

ADL-Basic general structure: 

ADL-Basic general structure

ADL-Basic field definition: 

ADL-Basic field definition Semantics identifies the nature, genre, meaning, or intellectual content of the item Content zero or more terms drawn from identified thesauri XML representation <!ELEMENT ...> Collection metadata implications collection metadata lists all referenced thesauri Query value single term from an identified thesaurus Query operator “is a” {(“Object Types”, “aerial photograph”), (“Geology Concepts”, “erosion”)} Type is a (“Object Types”, “image”) Type

ADL-Full: 

ADL-Full Encodes the full, native metadata in a standard syntactic representation RDF ADL’s generic encoding <source prefix=“MARC”>http://lcweb.loc.gov/marc</source> ... <group name="Data quality"> <field name="Accuracy" source="MARC:514g"> <value type="number" unit="meters">25</value> </field> <field name="Contour interval" source="MIL-B:06200a"> <value type="number" unit="meters">10</value> </field> </group>

Index/search services: 

Index/search services Core index/search service Based on ADL-Basic Boolean combinations of constraints on ADL-Basic fields and subfields (only) Support for other, more refined search services Utilizing ADL-Basic metadata mappings Based on ADL-Full

Browse/aggregation service: 

Browse/aggregation service

Collection metadata: 

Collection metadata Static Scope and purpose, maintaining agency, etc. Derived Referenced thesauri Referenced metadata standards Native  ADL-Basic metadata mappings Statistical summarization via browse/aggregation service

Gazetteer service (1/3): 

Stratford-upon-Avon Variant names Stratford upon Avon; Stratford Location N 52° 11’, W 1° 42’ Feature type populated place (NIMA); town (local) Time period 1196–present 805 Feature type U.S. telephone area code 37T Feature type UTM zone Mississippi Feature type drainage basin Gazetteer service (1/3)

Gazetteer service (2/3): 

Gazetteer service (2/3) Geographic namespace: spatial partition of a region into uniquely named subregions

Gazetteer service (3/3): 

map service client Gazetteer service (3/3)

Goals, revisited: 

Goals, revisited Find Discovery service based on rich collection metadata Uniform searching based on ADL-Basic More refined searching based on ADL-Basic and ADL-Full Browse/aggregation service Assemble, structure, publish Uniform use of collections Thesauri and inheritance of collections and digital objects support customization & structure Collections designed to span gamut big  small Use FEDORA-like extensible digital object model