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Information about XwalkProgress

Published on December 12, 2007

Author: Moorehead

Source: authorstream.com

Slide1:  Report on Progress Overview:  Overview First cut gazetteer database built Basic working demonstrator built simple interface for reference use basic machine2machine protocols adopted Servicing Go-Geo! Adaptation of ADL Feature Type Thesaurus (see separate handout) Outreach and stakeholder engagement underway geoXwalk - High Level Architecture:  geoXwalk - High Level Architecture The geoXwalk Server (Spatially enabled RDBMs) Web client Request via protocol (ADL, OGC, Z39.50) Information server Request via protocol (ADL, OGC, Z39.50) (human interaction) (machine2machine interaction) Gazetteer Database:  Gazetteer Database Built on ADL Content Standard Currently seeded with: OS 1:50,000 digital Gazetteer digital boundary data from UKBORDERS data sourced from other OS products - Strategi, Meridian, 1:250,000 gazetteer starting to add 3rd party data including Getty Accuracy enhanced and metadata support Current coverage: Geographical - GB Thematic - see below Slide5:  ADL Gazetteer Content Standard Geographic Feature ID Geographic Name Variant Geographic Name (R) Type of Geographic Feature (R) Other Classification Terms (R) Geographic Feature Code (R) Spatial Location (R) Street Address Related Feature (R) Description Geographic Feature Data (R) Link to Related Source of Information (R) Supplemental Note Metadata Information http://www.alexandria.ucsb.edu/gazetteer comprehensive description but with small set of core elements temporal aspects of names, footprints, relationships, … documents source, spatial accuracy/scale of footprint does permit explicit relationship types! Slide6:  Feature Typing need to incorporate a dictionary of allowed terms which defines each feature type typing supports queries such as “What schools exist in Leeds and where are they?” Show lakes in Cornwall hierarchy of feature types preferred propose to adopt the ADL Feature Type Thesaurus some problems… but ADL acknowledges these adapted thesaurus for UK hydrographic features . aquifers . bays . . fjords . channels . deltas . drainage basins . estuaries . floodplains . streams . . rivers . . . bends (river) . . . rapids . . . waterfalls Slide7:  geoXwalk gazetteer - current thematic content (based on adapted ADL Feature Type Thesaurus) Slide8:  Reference use Searching Geo-parsing & indexing The geoXwalk Server geoXwalk as digital gazetteer service: use cases Slide9:  Supporting reference: the “where is?” type of question What is at grid ref. NY 305 573 ? Where is Aberdour? What is the largest town in Nottinghamshire? List me all places ending with ‘kirk’ What parishes fall within the Lake District National Park? On what river is Dundee situated? Which Roman roads pass through Scotland? By what alternative names has York been known? + research use to resolve variant names etc. Slide10:  Demonstration Slide11:  Task: Find resource about 'Liverpool docks’ Search using a ‘traditional’ gazetteer might yield: Using spatial proximity in an active gazetteer, the search can be widened: Place County/UA Liverpool Liverpool Bebbington Wirral Birkenhead Wirral Bootle Sefton New Brighton Wirral Seacombe Wirral Seaforth Wirral Waterloo Sefton … that means more & better hits …. !!! co-ordinates allow (near) co-located places to be co-identified. Slide12:  Demonstration Slide13:  Supporting cross searching different services Co-ordinate footprints Parish names Place names Post code: L34 0HS? ‘Find resources for this postcode’ (NB postcode often used to geo-reference survey data files) Slide14:  Demonstration (Go-Geo!) Slide15:  Protocols Why adopt a protocol at all? agreed set of rules and interfaces (limit proliferation) ADL Query Protocol lightweight, generic, relatively simple to implement OGC Filter Encoding Specification fuller, highly flexible, more complex Z39.50 pervasive in JISC IE, not specifically for geo-spatial data, lack of support Slide16:  identifier-query identifier Return gazetteer entry identified by identifier Supported by geoXwalk name-query operator text Returns gazetteer entries which match text under text-operator operator geoXwalk supports the mandatory equals operator and the optional match-pattern operator footprint-query operator (polygon | box | identifier) Returns all gazetteer entries having a footprint that matches a query region according to spatial operator operator geoXwalk supports spatial operators within, contains and overlaps. Spatial extents can be specified by bounding box or identifier. 5 types of ADL query: ADL queries (contd):  ADL queries (contd) class-query thesaurus term Returns all gazetteer entries which belong to the class (feature type). geoXwalk supports class queries (but currently does not return sub-classes by default as the ADL does) relationship-query relationship identifier Returns all gazetteer entries having relationship relationship to a target gazetteer entry identified by identifier. geoXwalk does not support queries of this type because we do not hold explicit relationships between entities - they are derived implicitly from the geometries Slide18:  Demonstration m2m Outreach and evaluation:  Outreach and evaluation JISCmail list established leaflet produced project web pages available discussions with various stakeholders discussions with data providers report and outcomes of this meeting will be written up

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