Rules and Scripts Based Dynamic Spatial Data Catalogue Technique Study and Its Application

Catalogue technology has been widely used in spatial information organization, management and retrieval; it also plays vital effect in geography information system in organizing distributed and various spatial data resources. However, recent ways to describe catalogue tree, such as xml or database tables, lead fixed structure which is difficult to change, reuse and extend when facing masses of real-time spatial data. The directory service (OpenGIS Catalogue Services) standard developed by OGC (OpenGIS Consortium) only defines the directory service interoperable interface specifications but lacks of organizations and technology to implement. Thus, it is indispensable to develop a new method to manage masses of spatial data in spatial data warehouse or spatial data center systems in a facile, flexible and real-time way. Through analyzing common methods of representing and building catalogue system, this paper presents the novel concept of dynamic spatial data catalogue (DSDC) based upon these traditional model. Firstly, DSDC builds up a highly abstracted catalogue model for general directory description. Then, combining with the requirements of GIS application system, it developed a dynamic spatial data catalogue technique and mechanism using rules and scripts to produce the dynamic effect of catalogue representation. It detailedly introduced the key approach of the implementation using XML as the define language of rule, and using python as the script language. In this way, the catalog system will meet the requirements of faster development, easier extension, heterogeneous spatial data resource integration and real time reaction in a flexible way. DSDC technology is also an approach to build or integrate with any GIS systems rapidly. This paper discusses some applications of DSDC in various appropriate occasions, illustrates the integration of DSDC with MapGIS data center platform, and gives the application of DSDC in specific GIS application development and building- - process. The DSDC technology has been implemented and used in managing national 1:50000 basic geographic database resource and weather spatial data of Wuhan dynamically. Experiments prove that dynamic spatial data catalogue using rules and scripts has obvious advantages and will have huge potential in GIS applications.