Research And Application Of Spatio-temporal Data Model On Base State With Amendments In The Urban Green-land

At present, the research and application on spatio-temporal data model is a hot spot in the fields of spatio-temporal database. According to elementary theory of spatio-temporal data model, this paper explains the characteristics and advantages on spatio-temporal database model. It also proposes an efficient spatio-temporal data model in the further, which is a composite spatio-temporal data model based on base state with amendments. The model plays a significant effect in solving the problems of the traditional spatio-temporal data model based on base state with amendments in existence.First of all, the article analyzes two problems of traditional base state amending model in existence: the historical data retrieval is inefficient, the spatial relations in space-time object and the relations among spatio-temporal objects can not be handled easyly, such as disjoint , touch, cross, contain, summarized relationship, relationship between part and entirety, etc.Secondly, three methods which have improved the historical data retrieval. They are the methods of setting up graded index, the factor of variable granularity based on base state interval and the critical exponent on object change. The optimal method on fixing the distance of base state has been choosed out in the urban green-land. While, the theory of spatial relationships of hyper graph model is improved. It can solve the problems on the spatial relations in space-time object and the relations among spatio-temporal objects.Finally, according to the studies on these theory, a new composite spatio-temporal data model based on base state with amendments has been proposed to solve the problems of traditional base state amending model. The model consists of three parts: index, spatial objects, and change process. At the same time, by using the urban green-land as an example, the functions of temporal query and data change is completed successfully in the urban green-land GIS based on ArcObjects and Visual C++6.0. And, the new model has been verified.The studies have shown that the composite spatio-temporal data model based on base state with amendments improves the efficiency of historical data retrieval, and also simplifys the spatial relations in space-time object and the relations among spatio-temporal objects. Therefore, the model can provide the basic model for the application system which have a similar temporal and spatial variation, such as cadastral management system, urban traffic management system, census, land subdivision, etc. So, it has a certain practicality.