ISPRS WG II/3 Chongjun YANG Sept th 2003, Thailand Co-Chair of ISPRS WG II/3 IRSA/Chinese Academy of Sciences
WG II/3 Terms of References and Activities Systems for integrating geo-spatial data Integrated services involving economic, technical and political aspects Geo-spatial information distribution and accessibility systems using internet Development and validation of end-to end spatial data access systems Liaison with CEOS WGISS and other relevant organizations ISPRS Working Group II/3 Integrated Systems for Spatial Data Management
Interoperability of Spatial Data Service Chongjun YANG Sept th 2003, Thailand Co-Chair of ISPRS WG II/3 IRSA/Chinese Academy of Sciences
Interoperability of Spatial Data Service For Open System
1.Context 2.Components of Interoperability 3.Levels of Interoperability 4.Criteria for Interoperable System 5. XML,GML,WMT,C#,.NET 6.Example 7. Discussion & Cooperation Interoperability of Spatial Data Service
1. Context : GIS Computing Computing-Structured(Standlone System) Computing-Centred(Centre- System) Client-Server System(Local Network) Computing-Distributed System(Intranet/Internet)
Data Decision Knowledge Information SeSe rvicervice 1. Context
Data 1. Context : Trends Service GIIT mainstream
1.Context : Interoperable Mechanism of Internet Internet : TCP/IP Web: HTML(XML) HTTP API URI Little interoperability for spatial data
1.Context : Benefits of interoperable spatial data service ( 1) eliminating spatial data duplication. (2) reducing the effort required to manage and maintain spatial data. (3) facilitating application development activities. (4) providing a flexible computing environment with access to computing resources ranging from desktop machines to high-performance computers (supercomputers); and (5) reducing costs associated with data acquisition, management, maintenance, and conversion, model development, and overall operations.
- How should the exchanged data be represented? (data representation) - How should two systems communicate? (application communication protocol) - How should data be addressed across systems? (naming mechanism) - Which functionality should be available between systems? (application programming interface). 2. Components of Interoperability
3. Levels of Spatial Data Service Interoperability The more the interoperability mechanism knows about the spatial data, the advanced the degree of interoperability is.
No knowledge about spatial data knowledge of the structural (syntactic) aspects of the data knowledge of the schematic aspect of the data knowledge of the semantic data aspect 1) DATA KNOWLEDGE From simple to advanced interoperability: 3. Levels of Spatial Data Service Interoperability
2) scope of the data model 3) Name Space Management 4) Capabilities of Server API 3. Levels of Spatial Data Service Interoperability
(1) Decisive interoperability criteria, (2) Technology criteria, and (3) Implementation and software criteria. 4. Criteria for Interoperable System
Common data representation: Which data types are supported? level of data representation? is it public? is it a standard? (1) Decisive Interoperability Criteria
Server interface: which functionality is supported? is it extensible? Is it flexible? is it public? is it a standard? (1) Decisive Interoperability Criteria
Java COM/OLE CORBA/J2EE GRID … (2) Relevant Technology Criteria
Format-to-common format conversion via the data server: - Availability of software products (is a complete, stable system available?) - Diverse platform support (is the product available for most platforms?) - Software maturity - Support and Maintenance - Cost of software - Ease of hosting data via the system (3) Relevant Implementation and Software Product Criteria
Recommended by W3C in 1998, XML (eXtensible Markup Language) emerges as the second generation Web language for data interchange on the Web. Provides text encoding of all data. Uses a Document Type Definition or Schema to ensure document/data consistency. Over 200 XML derived languages. Offer real potential to significantly impact geo- spatial data and systems interoperability on the Web. 5. XML,GML,WMT,C#,.NET: XML
GML Project launched at OGC meeting, April 1999 GML provides a standard means to encode Geographic Info in XML. GML separates content from presentation. GML is focused on capturing geographic content. GML is styled into a presentation format such as SVG(Scalable Vector Graphics) for map drawing or other visualizations. GML is consistent with existing OGC standards for expressing geographic features. 5. XML,GML,WMT,C#,.NET: GML
GML DataServer Styling Engine Map Style Library HTTP TCP/IP Stylesheet Map Viewed in Web Browser Graphical rendering Figure. Process of GML Web Mapping
The Web Mapping Testbed, Phase I, is the first of OGC's planned Interoperability Initiatives, which involve sponsors and participants. Federal agency and corporate sponsors provide funding and a set of objectives related to geoprocessing interoperability. WMT has so far demonstrated two types of applications: Web Mapping Clients, and Web Mapping Servers. The Clients create requests that satisfy the Web Mapping Protocols. 5. XML,GML,WMT,C#,.NET: WMT
The main interfaces are the GetMap protocol (which identifies one or more layers to be displayed), the GetCapability Protocol (which allows the client the ability to discover the abilities of a server), and finally the GetFeatureInfo protocol (which allows the client to uncover the attributes of a displayed feature). Web Mapping Servers interpret requests that conform to the WMT protocols and generate appropriate objects that are returned to the querying clients. 5. XML,GML,WMT,C#,.NET: WMT
C and C++: powerful and flexible, but unproductive C# Microsoft solution, a modern, object-oriented building applications for the new Microsoft.NET serving both computing and communications.NET Internet-based integrated solution 5. XML,GML,WMT,C#,.NET: C#,.NET
6. Example 6. Example A New Spatial Search Engine – Enabling the Intelligent Geographic Information Retrieval in Internet Yuqi,BAI Chongjun YANG Institute of Remote Sensing Applications Chinese Academy of Sciences
Context: Using to search a text Using to search a map Question: May we search a map without using traditional search engine? 6. Example
Scenario : When you are reading news on the web, you maybe meet a place name, for example Afghanistan, and want to know where it is. Can you just simply select this place name and get the corresponding map? 6. Example
a.Design of a New Spatial Search Engine -1 Compatibility Data Sharing Modularity Component Sharing Interoperability Service Sharing Three Stages: <- 6. Example
a.Design of a New Spatial Search Engine -2 Design goals Automation: get command -> query -> render the result Interoperability: with any web mapping systems Integration: can be integrated with other existing applications seamlessly and easily. 6. Example
a.Design of a New Spatial Search Engine -3 Conceptual Design Modularization: For the Web Mapping Systems(WMS) Description: For the service interfaces of WMS Registration: a logically centralized, physically distributed registry centre 6. Example
a.Design of a New Spatial Search Engine -4 The Conceptual Architecture <- 6. Example
b.Prototype System-1 Geo-coding Service Map-providing Service 6. Example
b.Prototype System-2 Software packages used IBM Websphere UDDI Registry 1.1 VC Standards SOAP 1.2 UDDI 2.0 GML Example
b.Prototype System-3 6. Example
b.Prototype System-4 6. Example
b.Prototype System-5 6. Example
b.Prototype System-6 <- 6. Example
7. Discussion & Cooperation: a.Would rather provide spatial data service than only data b.Make all things(hardware,software, data, processing, etc.) as interoperable as possible c. International cooperation in developing interoperable technology
Thank you!