The Research And Application Of Spatio-Temporal Database In Road Equipment Management

Space, attribute and time are the three basic characteristics of geographical phenomena, they are also the essential data types of GIS database. Conventional GIS only describes the geographical space statically and abstractively with space and attributes. With the dramatic increase of geographic information, especially the wide use of time dimension, people began to make scientific researches on Temporal GIS. Temporal GIS can offer the tools that model and analyze the space, time, and hold the history or forecast the future of geographical events. At the present time, much progress has been made on the study of Temporal GIS. However, because of the complexity of spatio-temporal phenomena and the limitation of correlative theory and technology, there are always many problems remains in this study field.In this dissertation, we review the history of Temporal GIS, and analyze the existing problems and their causes. Then, we introduce the concepts of spatio-temporal data model combined with space and time in geographical world. We discusse with emphasis the characteristic and applicability scope respectively of several spatio-temporal data model at present, and analyze correlativity of spatio-temporal data in road equipment management. Base on it, we build the object-oriented spatio-temporal data model. With the analysis from concept design, logic design, we attach the temporal information directly on objects' attribute in order to make the intuitionistic expression on spatio-temporal change of data. Finally, the query language TSQL is advanced based on extending SQL, mainly extend the predication and function of SQL to put it more proper for querying spatio-temporal data. This article also labors the Data Definition Languages (DDL) sentence and Data Manipulation Language (DML) of TSQL. In query, we improve the traditional algorithm and rebuild the "From" clause, then a multilayer query of separating spatio-temporal restriction is built. We can realize the algorithm on .NET flat.Take the Luwan borough of Shanghai as an example, we achieve the visual query of spatio-temporal data in road equipment management, the conception of space and time is illuminated practically and visually, and the dual implementation of object-oriented spatio-temporal data model applied to both graphical data and attribute data is revealed. The application shows that the spatio-temporal data model designed in this study makes practical sense to perform the reappearance of historical state and backdating effectively.