2002 National Report for China
Activities in the Area of Metadata and other Standards in P. R. China
Prepared by Du Daosheng
Wuhan Technical University
Wuhan, China
1. Modify and Perfect Existing Geographical Information Standards
To realize spatial data sharing under network environment, a few standards among those, which have been issued and implemented in China, should be modified and perfected, see table1.
Tab1. Geographical Information Standards Issued and Implemented in China
| Standards’ Name | No. |
| 1. Codes for the administrative divisions of the People’s Republic of China | 2260-1999 |
| 2. Classification and codes of water path information | 17735-1999 |
| 3. Classification and codes for soils in China | GB/T 17734-1999 |
| 4. Classification and codes for economical types | GB/T 12404-2000 |
| 5. Name codes of countries and districts in the World | GB/T 2659-2000 |
| 6. Classification and codes for thematic map information | GB/T 18317-2001 |
| 7. River name codes in China | Ministry of Water Resources of P. R. China |
| 8. Classification and codes for national land information | State Bureau of Surveying and Mapping of P. R. China |
| 9. Quality requirement for digital products of surveying and mapping—Part 1: Quality requirement for digital line topographic map, digital elevation model | GB/T 17941.1-2001 |
| 10. Testing of quality and assessment method for digital products of surveying and mapping | GB/T 18316-2001 |
| 11. Digital topographic map series and basic requirement | GB/T 18315-2001 |
| 12. Format for geo-spatial data exchange | 17798-1999 |
| 13. Interface specification between topographic maps database and place names database | 17797-1999 |
| 14. Graphical symbols of common information used on the maps—common used symbols | 17695-1999 |
1. 1 Improve Metadata Standard for Spatial Data
Metadata is used to describe contents, quality, express schema, spatial references, management styles and other features of geographical dataset. It is one of core standards for geographical spatial information sharing. Nowadays, it is applied for archiving, issuing, inquiring spatial dataset and provides a common describing elements and standards for spatial dataset. Elements or complex elements for describing dataset, dataset series and entity attributes will be formed, and the definition and the range of values for those elements and interrelationship among them should also be included in metadata standard. The choice for elements is based on four aspects: the availability of dataset, the applicability of dataset, how to obtain and how to use such dataset.
From 1996 to 2000, a number of researches are implemented for metadata standard in theory and practice in China and a series of drafts are suggested. With the development of technologies, some contents should be modified, include:
(1) Modify and complement elements for the contents of metadata;
(2) Modify existing normal forms and dictionary and add UML notation;
(3) Extend standard’s application schema and add XML and DTD description;
1. 2 Set down encoding rule for Geo-Spatial Information
Semantic Inconsistency is a key urgent problem that should be solved for geographical information sharing. Firstly, it is necessary for setting down encoding rule to define the classification of geo-spatial information, the concepts of geographical units, establish corresponding model for geographical units and specify the principles for data sharing. Then, provide standardized definition of spatial and attribute elements of common geo-spatial dataset in the basis of conceptual data model, and identify encoding objects and uniform encoding rule. Furthermore, it is necessary to make efficient integration of data in practice.
1. 3 Revise and improve standard for geo-spatial data transformation format
The standard of Geo-spatial data transformation format in China is issued by State Bureau of Quality and Technical Supervision of P. R. China in 1999, and is implemented and applied comprehensively in whole country. With the development of technologies, some contents of this standard should also be modified, include:
(1) Add the definition of complex object and its data transformation format for Vector data by means of OpenGIS data model;
(2) Expand those transformation formats that are only aimed at digital orthographical Image formerly to general format for terrestrial Images, which include the definition for a variety of aeronautic image and satellite remote sensor image, metadata for image products, data format for various images;
(3) Original data format for DEM is not to be modified completely.
1. 4 Modify and Revise standard for fundamental geographical information symbols
2. Develop Geographical Information Deliveries and Service Standard
Administrative specification for Geographical Information deliveries and service is essential for expanding and deepening the application of geo-spatial information and realizing spatial information sharing. It includes:
(1) Specification for the schema of geo-spatial delivery and service;
(2) Specification for the integrative methods of network sharing service for geo-spatial information;
(3) Specification for data maintenance and data issue;
(4) Specification for the realization of Geographical Information Deliveries and Service Standard.
3. Develop Spatial Data Inter-manipulation Standard and Agreement
There are some major research directions in follows:
(1) Develop abstract specification for spatial data Inter-manipulation;
(2) Develop and set down specification for the realization of spatial data Inter-manipulation;
(3) Realize the specification for spatial data Inter-manipulation.
4. Network Environment Construction for Spatial Data Sharing
Standard and agreement for spatial data sharing under network environment can be categorized into three levels:
(1) Spatial dataset standards, which include metadata standard of spatial data, semantic standard, encoding standard, spatial data quality standard, spatial data transformation standard, symbols standard for spatial data visualization. Those form a system for characteristic description and data transformation standard of spatial data and are the basis for spatial data deliveries and service standard and spatial data inter-manipulation standard.
(2) Spatial data deliveries and service standard, which is related to document level(dataset) spatial data sharing and delivering service.
(3) Spatial data inter-manipulation specification, which is related to real-time sharing and inter-manipulation of spatial objects in isomeric spatial database.
Corresponding software packages are developed by means of those standards and specifications. Furthermore, State Information Center of P. R. China(SICC), National Geomatic Center of China(NGCC), Information Center of Ministry of Land and Resources of P. R. China(MLRC), China Remote Sensing Satellite Ground Station (RSGS) of Chinese Academy of Sciences, establish data deliveries center respectively. Nowadays, a whole experimental system in which standards and specifications, supporting software packages and the development of data environment are involved is formed in China.
© Copyright, ICA Standards Commission, 2002