An open software framework for Web Service-based geo- processes Theodor Foerster FOSS4G 2006 – Lausanne, Switzerland

Theodor Foerster 2 Contents Motivation The standard The architecture The use case: generalization Getting involved

Theodor Foerster 3 Motivation Geospatial data available on the web Network capacity and computational power available Geospatial information is carried out by geo-processes (buffering, generalization,…)  Web-based geo-processes Web-based geo-processes should be interoperable  Standard for web-based geo-processes

Theodor Foerster 4 Additional benefits Interoperable web-based geo-processes - Improve knowledge exchange through the web  Within a community  Through out domains - Geo-processes become easily adoptable - Provide high scalability for clients - Web-based geospatial information next step!  Geo-processes become interoperable through Web Services OGC web-enables geo-processes through the Web Processing Service (WPS) specification

Theodor Foerster 5 Notion of the WPS Service communication based on HTTP and XML No limitations on certain types of processes No limitations on the data - Supports raster and vector data - Literal variables (e.g. buffer size)

Theodor Foerster 6 WPS operations GetCapabilities - Service description - Access description - Brief process descriptions DescribeProcess - Full process description Execute - Process execution

Theodor Foerster 7 … … Buffer ProcessingService? REQUEST=DescribeProcess& Identifier=Buffer& SERVICE=WPS& VERSION=0.4.0 Buffer … … BufferResult $XML_Geometries <ProcessDescription Buffer … geometry 1 width … … BufferResult … ProcessingService? REQUEST=GetCapabilities& SERVICE=WPS Buffer geometry $XML_Geometries width 100 WPS in action - Buffering ClientWPS Network request response request response request response Inspired by P. Schut’s presentation at the OGC TC Meeting in Huntsville 2006: “WPS RFC responses”

Theodor Foerster 8 Additional Features Supports long-term processes by storing - Handles drawback of HTTP - Avoids recalculation - Status of processes is callable Supports chaining (limited) - For data retrieval & processing Standardized error messages

Theodor Foerster 9 Design goals Pluggable Scalable Easy to install Standards compliant

Theodor Foerster 10 Framework architecture Web Processing Service WPS GetCapabilitiesExecuteDescribeProcess Algorithms Repository … … Douglas Peucker Algorithm Data Handler Repository … … GML Data Handler Communication over the web using HTTP WPS-client

Theodor Foerster 11 Implementation Implementation available at 52north under GPL license Implements all features of the specification - Storing process results - ComplexReferences Fully java-based, running on tomcat Incorporated APIs: - Servlet API - Xml-beans - JTS Service plus client (JUMP plug-in) available Basic data handlers Implementation applied for SWE and generalization

Theodor Foerster 12 Use case: generalization Geospatial data  geospatial information - Scale - User & use Model and cartographic generalization ITC’s generalization research project - Automated web-based generalization - User-centered generalization - Focus on Dutch topographic data First example: simplification - Reduces the number of geometries - Deletes unimportant aspects of data - Important for mobile applications - Mostly not satisfying in cartographic terms

Theodor Foerster 13 Example – Simplification Registering the service and configuring your process…

Theodor Foerster 14 Example – Simplification …Visualize the result! original dataprocessed result

Theodor Foerster 15 Outlook Integration into geoserver/geotools as DataStore Adding more data handlers (GML 3.x) Improving the communication mechanisms - Asynchronous communication - Incorporating notification mechanisms Enabling smart storing - WFS - WCS Giving feedback to OGC

Theodor Foerster 16 More information 52n incubator Wiki - Documentation  Installation  Examples - Binaries and sources - CVS access on sourceforge Accessible through the Processing home on the Wiki or directly: - ProcessingService

Theodor Foerster 17 Thank you for your attention! Watch out for other 52north Theodor Foerster Hengelosestraat AE Enschede Tel: +31 (0)