1. The Frontier of GIS GIS Web Services Nadine Alameh, Global Science & Technology Next Generation of Community Statistical Systems Tampa, Florida March 14, 2002

2. Evolution of GIS: From Stand-alone to Web Services Stand-alone systems (workstations) Data tightly integrated with system Desktop mapping Databases with spatial extensions, SDE Embedabble GIS components Web mapping Unbundled GIS into autonomous services Distributed and interoperable GIS services -Lower costs of PC -Faster processing -Internet (html, cgi, java) -Client/Server -Middleware (Corba) -Wireless and mobile computing -Internet technologies (eg.XML) -Role of GIS in Enterprises -Availability spatial data

3. March 14, 2002 Evolution of GIS: From Stand-alone to Web Services

4. March 14, 2002 GIS Web Services I Web Mapping Service Web Feature Service Portrayal Service Web Mapping Service Bundled Service Address Match Service Mobile Devices: Retrieve image centered at current location Browsers: Retrieve several overlayed images as one Standardized Interfaces Information Systems: Perform business analysis based on customers’ geographical distribution Registry Service Web services are self-contained, self-describing, modular applications that can be published, located, and dynamically invoked across the web. Applications can be dynamically assembled from multiple network-enabled web services for use by a variety of client applications.

5. March 14, 2002 GIS Web Services Architecture Lower the learning curve Share data and services more effectively I Web Mapping Service Web Feature Service Portrayal Service Web Mapping Service Bundled Service Address Match Service Mobile Devices: Retrieve image centered at current location Browsers: Retrieve several overlayed images as one Standardized Interfaces Information Systems: Perform business analysis based on customers’ geographical distribution Registry Service Cut system integration and deployment cost Learn, use/get and pay only for what you need

6. March 14, 2002 Service Chaining When a task needed by a client cannot be provided by a single service, but rather by combining or pipelining results from several complementary services. Reprojection Service Web Coverage Service Web Coverage Service Portrayal Service Portrayal service assembles orthoimage from several imagery services Reprojection servicereprojects the image from one coordinate system to another one Vector Data Provider Service Vector data provider service returns a certain layer at the extent specified Overlay Service Overlay service overlays the input image and the vector data and sends the overlay to the client To Client Web Coverage Service

7. March 14, 2002 User-Defined Chaining Chaining is transparent: User defines and controls the order of execution of the individual services. Address Matching OrthoImagery Service Re-projection Service Client Catalog Service Address Matching OrthoImagery Service Re-projection Service Client Catalog Service

8. March 14, 2002 Aggregate Service Chaining is opaque: the services appear as a single service which handles all coordination of the individual services behind the aggregate service. The user has no awareness that there is a set of services behind the aggregate service. Address Matching OrthoImagery Service Re-projection Service Client Catalog Service Aggregate Service

9. March 14, 2002 Workflow-Managed Chaining Chaining is translucent (in between transparent and opaque): execution of the chain is managed by a workflow service. User may select a chain of interest that is executed by the workflow service. Client Address Matching OrthoImagery Service Re-projection Service Workflow Service Catalog Service

10. March 14, 2002 Opportunities Portals for Community Statistics Field  Focus on providing specialized aggregate and workflow services  Customize chains and combine services to meet community statistics needs Sophisticated tools:  Tools for users to construct and customized their own chains  Tools for finding the right services based on characteristics such as service scope, performance, service/data quality, price  Tools for constructing “optimal chains”: least expensive, minimum number of constituent services, most accurate results, etc. Challenge  Sustainability of such a service-based architecture requires standards and well-defined interfaces for the underlying services

11. March 14, 2002 Current Status Web Services Technologies  WSDL for service description  UDDI for service discovery  SOAP for passing XML-encoded data  IBM WSFL and MS XLANG for service composition and process languages for orchestrating web services into larger-scale applications OGC work  Categorization of services: data services (WMS,WFS,WCS), processing services, registry services  Encodings: SLD, GML  WMS/SLD/CPS set a precursor precedent for service chaining in the web services environment