The Methodology Of Constructing Spatio-Temporal Data Model Based On The Approach Of ORM

One of the major functions of GIS is data management and data updating is one of the most fundamental requirements of the data management. The keeping geographical data in always new has become an important measure in terms of its application value. At present, the kernel of GIS has shifted from data production to data updating which is the symbol of the sustainable development of GIS. Moreover, the temporal tense of GIS was continually one of the hot topics in GIS research field. However, this research on the temporal tense of GIS is still in the stage of keeping varying opinions from different researchers because of the complexity of the subject. The spatio-temporal data model (STDM) is both the key problem and the most difficult issue in the temporal geographical information system (TGIS). It is of importance to constructing STDM in terms of practical requirements and the future development tendency of GIS.In this thesis, the present conditions and development tendency of the techniques for constructing STDM in foreign countries and in China are presented and analyzed, the present STDM are discussed, the advantages and disadvantages of ER and UML are explored, and the detail of constructing STDM is in detail described through incorporating a totally new modeling method, i.e., Object-Role Modeling (ORM). The emphasis of the research of this thesis was put on the features of spatio-temporal data and its conceptual models as well as the process and methodology of spatio-temporal modeling. Based on these and using the spatial data of the real estate of XiangTan City in Hunan Province and ORM data modeling methodology the spatio-temporal data model (STDM) for real estate management was constructed.The main results and conclusions of this thesis are as follows: (l)There is no uniform standard in STDM and the Object-Oriented Method is the tendency of STM in future; (2)ORM is a totally new method for STM; (3) The spatio-temporal granularity as an important characteristic of STDM, is one of the most key element in STM;(4)The method of STM was provided on the basis of point view of applied system; and (5) The method of management for spatio-temporal data of real estate was developed based on the analysis of the characteristics of the real estate spatial data.In a word, the method of model constructing based on ORM and described in this thesis has some new meanings. Besides, the data characteristics, conceptual models as well as the process and method of the spatio-temporal modeling which are all presented and discussed in this thesis have provided the experiences for the similar studies of the spatio-temporal modeling. Moreover, this study has a certain practical values because it will be beneficial to solve the management problems of spatio-temporal data in applied systems.