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Mikael Johansson Lars Harrie National Land Survey of Sweden. Using Java Topology Suite for Real-time Data Generalisation and Integration. DISPOSITION Background Technical environments for real-time generalisation JGML Outlook. Technical environments for real-time generalisation of GML-data.
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Mikael JohanssonLars HarrieNational Land Survey of Sweden Using Java Topology Suite for Real-time Data Generalisation and Integration
DISPOSITION Background Technical environments for real-time generalisation JGML Outlook
Technical environments for real-time generalisation of GML-data All generalisation performed in the database environment (i.e., before GML-data is created) Solutions based on commercial products XSLT-transformation Task oriented API
All generalisation performed in the database environment + fast access methods + support for topological and geometrical queries + easy to tailor for specific data - integration is not supported - dependent on type of database system
Solutions based on commercial products + already implemented generalisation routines + support for topological and geometrical queries + easy to tailor for specific data - slow convertion from and to GML - dependent on type of software
XSLT-transformation (with java extension) + relatively fast + completely based on free standard solutions difficult to create generalisation routines for group of objects little support for method implementations
GML-file XSLT-transformation SVG-file Generalisation using XSLT(Tiina Sarjakoski, Lassi Lehto)
Task oriented API + developed specifically for the current problem + completely based on free standard solutions - requires much own development - tends to be data dependent (difficult with generic solutions)
XSLT transformation User GML-file SVG-file Spatial database 1 Spatial database 2 GML GML JGML JGML: a task oriented API forreal-time generalisation and integration
JGML packages • Java Topology Suite (Vivid Solutions) • GML reader classes (using Xerces from Apache) • Basic data classes according to OGC- standards • Object type classes • Generalisation classes • Viewer (only for developing purposes)
Java Topology Suite • JTS conforms to the Simple Features Specifications for SQL published by the OGC • JTS provides a complete, consistent, robust implementation of fundamental 2D spatial algorithms • JTS is fast enough for production use • JTS is written in 100% pure Java • JTS is open source
JGML - summary • Solely based on free products • Conforms to OGC-standards • Good geometry and topology handling • (as good as “any” commercial GIS API) • Developing time: 2 persons, 1.5 months • work per person.