1. June 9-11, 2004 Carleton University Ottawa Canada OGC in Open Source Products Tom Kralidis Jeff McKenna Peter Pulsifer Bart van den Eijnden June 9-11, 2004 Carleton University Ottawa Canada

2. Interoperability Overview Benefits of OGC in the Organization Examples / Demos OGC / Open Source Issues Comments/Questions/Discussion

3. June 9-11, 2004 Carleton University Ottawa Canada Interoperability Overview Benefits of OGC in the Organization Examples / Demos OGC / Open Source Issues Comments/Questions/Discussion

4. Infrastructure Many pieces working independent of make, model Open interface –Can communicate with other things Transparent / Invisible Cooperative Distributed

5. The Distributed Approach Distributed Spatial Data infrastructure Cost / Feasibility One Source Up-to-date Data Data Management Issues Less: –Local storage space –redundant data How? –Web Services

6. Web Services Independent of –operating systems –programming languages –Organizations How? –non-proprietary data / messaging standards eXtensible Markup Language (XML)

7. Web Services Until recently everyone is developing in their own little world (metadata => data => applications) From functionality to interoperability Internet is driving these changes: no net, then little reason to interoperate Being “open” is a strong selling point –E.g. VCR cassettes: VHS vs. BETA –E.g. mix and match your home stereo system components

8. Web Services- Benefits Lower software integration costs Maintaining legacy systems Using standards lowers IT costs of collaboration with external partners, vendors, clients

9. Web Services Architecture Approach Applications e.g., Transportation Planning, Climate Change Monitoring, Site Assessment Services e.g., Metadata Service, gazetteer service, Web Map Service Data e.g., topographic, thematic, imagery, toponymy, metadata Users Other Applications For Example… A trip planning web site that calculates the best route between two cities uses Gazetteer service, Road network server, Web mapping service based on Geographical Names, Road network features Base maps

10. OpenGIS Consortium Standards body for geospatial processing over the Internet –Free, public specification –Rapid specification development using Technology integration experimentation Develop and spec in parallel Testbeds –Sponsor requirements –Industry participation

11. OGC Specifications WMS WFS WCS Web Map Context GML SLD Filter Catalog WCTS Grid Coverages Location Services Simple Features –CORBA –SQL –OLE/COM

12. Web Map Service (WMS) Provides images of map data defined by a geographic / spatial component Provides point based query functionality Interoperable means of map compositing

13. Web Map Service (WMS) Interoperable, ‘just-in-time’ approach to map delivery Map compositing from multi-servers

14. GeoGratis – http://geogratis.gc.ca/ Web Mapping: Phase I Toporama: http://toporama.cits.rncan.gc.ca/

15. Web Mapping: Phase I Interoperability Common Standards Services Interoperability Common Standards Services

16. Web Browser Viewer Client Map Server internet Web Map Servers Web Mapping with WMS

17. Web Map Service (WMS) Provides images of map data defined by a geographic / spatial component Provides point based query functionality OGC adopted specification –1999: Version 1.0.0 –2001: Version 1.1.0 –2002: Version 1.1.1 CGDI endorsed specification

18. Web Map Service (WMS) HTTP-based communication –HTTP GET or POST mechanism Operations GetCapabilities GetMap GetFeatureInfo (optional) –Operation keywords are case-insensitive –Operation values are case-sensitive

19. Web Feature Service (WFS) Feature level access to spatial data –Finer grained access and query Spatial and non-spatial query capability –Attribute and / or geometry Returns GML –Can further transform with XSLT to SVG, style with SLD, etc. Transactional capability –INSERT, UPDATE, DELETE, LOCK, … Security considerations

20. Web Feature Service (WFS) GetCapabilities –Provides XML ‘Capabilities’ or service functionality metadata, and feature metadata –Parameters Version (version of specification) Service (multiple services may exist from this service, e.g. WMS, WFS, WCS) Request (GetCapabilities) http://ceoware2.ccrs.nrcan.gc.ca/cubewerx/cwwfs/cubeser v.cgi?datastore=CEOWARE2&version=1.0.0&service=WF S&request=GetCapabilities

21. Web Feature Service (WFS) DescribeFeatureType –Provides schema information about a feature type (fieldnames, data types) –Parameters Version (version of specification) Service (multiple services may exist from this service, e.g. WMS, WFS, WCS) Request (DescribeFeatureType) Typename (name of feature type) http://ceoware2.ccrs.nrcan.gc.ca/cubewerx/cwwfs/cubeser v.cgi?datastore=CEOWARE2&version=1.0.0&service=WF S&request=DescribeFeatureType&typename=EOS_DAT A_GATEWAYS

22. Web Feature Service (WFS) GetFeature –Provides query interface of data –Parameters Version (version of specification) Service (multiple services may exist from this service, e.g. WMS, WFS, WCS) Request (GetFeature) Typename (name of feature type) Filter (more on this later) http://ceoware2.ccrs.nrcan.gc.ca/cubewerx/cwwfs/cubeser v.cgi?datastore=CEOWARE2&version=1.0.0&service=WF S&request=GetFeature&typename=EOS_DATA_GATEW AYS

23. Geography Markup Language (GML) XML encoding of geospatial information –XML dialect Basic application framework for handling geospatial information Enables complex features & feature associations between data Human-readable Can be processed by many XML tools in various development environments

24. Geography Markup Language (GML) GML Schemas Geometry Definitions Application Schema Information Community Definition Instance Document Data Instance As static data or through Service Instance

25. Geography Markup Language (GML)

26. New features in version 3.0.0 –Topology –Temporal –Enhanced Geometry –Coverages –Units of Measure

27. Styled Layer Descriptors (SLD) Symbolization to map data Styling Addresses lack of symbolization within current and past OGC services Cartographic design of GeoData Augments OpenGIS specifications –Can custom style WMS content –Can custom style WFS content

28. Styled Layer Descriptors (SLD)

29. Example of an SLD document: http://cgdi- dev.geoconnections.org/prototypes/sld/gc db.xml

30. Filter Encoding XML Definition of data query language for online services –GML used for geometry querying semantics –Used as filter grammar for OpenGIS WFS –Stand alone specification Can be applied to any service as a query approach

31. Filter Encoding Example: ORGID> CCRS Used in OGC WFS –http://ceoware2.ccrs.nrcan.gc.ca/cubewerx/cwwfs/cubeserv.cgi?datasto re=CEOWARE2&version=1.0.0&service=WFS&request=GetFeature&ty pename=EOS_DATA_GATEWAYS&filter= ORGID> CCRS

32. OpenGIS Web Map Context Documents - Overview ‘bookmarkable’ XML encoding of state of a web mapping application Analogous to ‘project’ files in most popular GIS software packages Enables sharing of application scenarios, demonstrative presentations, etc.

33. Web Mapping – Same data; multiple applications (OpenGIS Web Map Context Documents)

34. June 9-11, 2004 Carleton University Ottawa Canada Semantic Interoperability Ability to share meaning rather than simply exchange data Semantic heterogeneity: –Same ‘symbol’/term different meaning –Different terms similar meaning OGC currently proposes consensus approach to dealing with semantic heterogeneity Moving towards the use of formal Ontologies

35. June 9-11, 2004 Carleton University Ottawa Canada Tools –Glossaries and data dictionaries –Thesauri and Taxonomies –Metadata, XML Schemas & Data Models (i.e. ISO 19115, GML, UML) –Formal ontologies and inference: Description logics (DAML+OIL) <-open standard

36. June 9-11, 2004 Carleton University Ottawa Canada Interoperability Overview Benefits of OGC in the Organization Examples / Demos OGC / Open Source Issues Comments/Questions/Discussion

37. June 9-11, 2004 Carleton University Ottawa Canada No reinventing the wheel Plug-and-Play with other standards-based systems Multi Vendor Interoperability Underlying system could change – interface remains standards-based –Less impact on end clients –Not tied to specific solutions

38. June 9-11, 2004 Carleton University Ottawa Canada Interoperability Overview Benefits of OGC in the Organization Examples / Demos OGC / Open Source Issues Comments/Questions/Discussion

39. June 9-11, 2004 Carleton University Ottawa Canada ProductURLOGC Specification(s) UMN MapServerhttp://mapserver.gis.umn.edu/WMS,WFS,Context,SLD Filter,GML PostGIShttp://postgis.refractions.net/Simple Features for SQL MapBuilderhttp://mapbuilder.sourceforge.net/WMS,Context deegreehttp://deegree.sourceforge.net/WMS,WFS,WCS,WCAS WFS-G,WTS,WCTS GeoServerhttp://geoserver.sourceforge.net/WFS-T maplabhttp://www.maptools.org/maplab/index.phtmlWMS Chameleonhttp://www.maptools.org/chameleon/index.phtmlWMS,Context,WFS inlineWMShttp://sourceforge.net/projects/inlinewmsWMS JUMPhttp://www.vividsolutions.com/jump/GML GEOShttp://geos.refractions.net/Simple Features for SQL gml4jhttp://gml4j.sourceforge.net/GML MySQL Spatialhttp://www.mysql.com/OGC Geometry Model MapSurferhttp://mapsurfer.sourceforge.net/WMS PyOGCLibhttp://pyogclib.sourceforge.net/WMS QuickWMShttp://www.inovagis.org/quickwms/WMS Studiohttp://www.maptools.org/studio/SLD,Context,WMS OpenMaphttp://openmap.bbn.com/ GeoToolshttp://www.geotools.org/GML,SLD,Grid Coverages,WCTS,Filter

40. June 9-11, 2004 Carleton University Ottawa Canada Demo 1: application framework based on OGC standards and Open Source. Open Source GIS products used: UMN Mapserver Chameleon and PHP/Mapscript OGR (as a PHP module) Deegree WCaS (Web Catalog Server)

41. June 9-11, 2004 Carleton University Ottawa Canada Application function: find services Uses: OGC Web Services Stateless Catalog Profile 0.0.6 (WCAS) ISO19119 datamodel

42. June 9-11, 2004 Carleton University Ottawa Canada Application function: find layers Uses: OGC Web Services Stateless Catalog Profile 0.0.6 (WCAS) ISO19115 datamodel Layers are coupled to services in the ISO19119 datamodel, so an extra request is necessary to find the service on which the layer is available

43. June 9-11, 2004 Carleton University Ottawa Canada Application function: querybuilder Flow: Perform DescribeLayer request on SLD WMS Perform DescribeFeatureType on associated WFS to get list of columns Use SLD + Filter to highlight features on map

44. June 9-11, 2004 Carleton University Ottawa Canada Application function: download shapefile Flow: Perform DescribeLayer request on SLD WMS Perform GetFeature with BBOX Filter on associated WFS using AOI defined in application Use OGR to convert GML to shapefile

45. June 9-11, 2004 Carleton University Ottawa Canada Demo 2 (Jeff McKenna)

46. June 9-11, 2004 Carleton University Ottawa Canada Interoperability Overview Benefits of OGC in the Organization Examples / Demos OGC / Open Source Issues Comments/Questions/Discussion

47. June 9-11, 2004 Carleton University Ottawa Canada OGC / Open Source Issues General –“OGC Compliant” – be careful! –Namespaces in OGC XML-based documents

48. June 9-11, 2004 Carleton University Ottawa Canada OGC / Open Source Issues General –XML (GML) is very expressive yet very verbose -> performance problems –Researchers working on ‘feature streaming’ to deal with this issue (not yet in OGC process) –Applicability of specs in functional applications: bridging the gap –slow emergence of specs

49. June 9-11, 2004 Carleton University Ottawa Canada OGC / Open Source Issues Semantic –Current consensus approach may limit use outside of simple domains (i.e. where concensus cannot be achieved) –OGC is not the only standard -> ISO, FGDC, Domain specific, W3C -> requires a ‘reference ontology’ to mediate between standards

50. June 9-11, 2004 Carleton University Ottawa Canada Comments/Questions/Discussion Thanks! Tom Kralidis (tom.kralidis at ec.gc.ca) Jeff McKenna (mckenna at dmsolutions.ca) Peter Pulsifer (pulsifer at magma.ca) Bart van den Eijnden (bart at geodan.nl) June 9-11, 2004 Carleton University Ottawa Canada