1. Implementation of a Data Node in China's Spatial Information Grid Based on NWGISS Dengrong Zhang, Le Yu, Liping Di zju_rs@126.com Institute of Spatial Information Technology (ISIT) Department of Earth Science Zhejing University (ZJU)

2. 2  Introduction  SIG Resources and Data Nodes  A SIG Data Node Based on NWGISS  Application and Efficiency Test  Conclusion Outline

3. 3  Introduction  SIG Resources and Data Node  SIG Data Node Based on NWGISS  Application and Efficiency Test  Conclusion Outline

4. 4 Introduction  Effectively access and share vast isomerous and distributed spatial data is a key technology for extensive GIS applications.  ISO TC211 and OGC provide standards for sharing and interoperating geospatial information.  Spatial information Grid (SIG) is a web-based infrastructure and technology system of spatial information in China  NWGISS is a web-based, multiple OGC standard compliant data distribution system developed by the Laboratory for Advanced Information Technology and Standards (LAITS), George Mason University.

5. 5 Open GIS Consortium (OGC)  Specifications for establishing spatial information grid (SIG) data node include: –Web Coverage Service (WCS) –Web Feature Service (WFS) –Web Map Service (WMS) –Catalog Service/Web (CS/W) –Geography Markup Language (GML)

6. 6  Introduction  SIG Resources and Data Node  SIG Data Node Based on NWGISS  Application and Efficiency Test  Conclusion Outline

7. 7 (Tang Yu et al, 2004) SIG Open Architecture

8. 8 SIG Resource Layer

9. 9 SIG Data Node  Function of SIG data node is processing spatial data in distributed spatial data file server, spatial database server, remotely sensed imagery server normatively, organizing data to specific structure for easier managing, accessing and using.  There are two requirements for these node: –1) providing coverage services, map services, feature services and catalog services; –2 ） complying with OGC specifications.

10. 10  Introduction  SIG Resources and Data Node  SIG Data Node Based on NWGISS  Application and Efficiency Test  Conclusion Outline

11. 11 NWGISS Interoperation Data Server Layer Architecture (NWGISS, http://nwgiss.laits.gmu.edu/introduction.htm)

12. 12 Structure of SIG Data Node

13. 13 Implementation of SIG Data Node Based on NWGISS  Providing MODIS data to SIG  Taking GMU LAITS’s NWGISS as core software  WCS 1.0 standard compliant  Three formats: HDF-EOS4, GeoTiff, NITFF  ISO19115 international standard was employed to describe the dataset  ISO19119 was employed to register the data access service

14. 14  Introduction  SIG Resources and Data Node  SIG Data Node Based on NWGISS  Application and Efficiency Test  Conclusion Outline

15. 15 Application  To validate the SIG data node, a SIG validating platform is established. Environment of OGC web service, the function of SIG service registration center, spatial information retrieval engine, engine for assignments management and services coroutine and resource management are validated by this platform.  All interface in SIG data node comply with OGC specifications. Three access modes will be adopted for different application intention, there are: –Web Service mode –Web application mode –Desktop application mode

16. 16 Efficiency evaluation  Responding to standard OGC requests and return specific spatial data under different network environment  Any OGC WCS1.0-compliant geospatial information analysis system client can access the data nodes distributed at different location and get back geospatial data and completes comprehensive analysis locally  Interoperable accesses between windows data node and Linux data node also shows a good capability of data sharing under isomerous operation environment

17. 17  Introduction  SIG Resources and Data Node  SIG Data Node Based on NWGISS  Application and Efficiency Test  Conclusion Outline

18. 18 Thank you for your attention!