Incremental Updating Of Cadastral Database Based On Topological Relationship

Incremental updating of cadastral database means that the core database is updated when any geometric or semantic changes occur, and that the changes are recorded, the updating process can be tracked, the updates are provided successively to users. During such a process, a set of editing operations is needed to add, delete or amend cadastral spatial objects, to solve spatial and temporal conflicts problems, maintain spatial and temporal consistency of the records. So far, the updating of core cadastral database is carried out manually and interactively. During this process a large amount of editing operations are needed, so the process is an error-prone, labor-intensive and difficult to maintain the topological consistency one. Our study aims to automate or semi-automate the incremental updating process of cadastral database. An incremental updating approach based on the topological relationship between parcels is proposed in this paper. The main works finished are listed as follows:1) At first, the author analyzed the topological relationship between cadastral entities, such as the topological properties of cadastral entities, binary topological relationship between cadastral entities at the same time, spatio-temporal topological relationship in cadastral changes. The description and computation speciality of cadastral topological relationship are concluded.2) In order to satisfy the speciality of cadastral topological relationship' description and computation, a method of cadastral entities' topological relations description and computation, simply called WID3 is presented. In this method, a spatial object is treated as a whole, the content, dimension, Euler number and the node' degree of two objects' intersection and difference are used to distinguish the topological relationship. Euler number of parcels' difference is used to distinguish the relationship between parcels; the node' degree of boundary lines' intersection is used to distinguish the relationship between boundary lines. Using WID3, the topological relationship between cadastral entities is described.3) Then an identification method of cadastral entities' spatial changes based on WDM is presented, which at first describes the more detailed spatial change types of split, union, modification of the common border between two parcels using WID3, then the change types of each entities involved in the subdivision changes are determined according to the topological relationship between the objects before and after the change process. Because the appearance frequency to each detailed spatial change is very different, we introduce Huffman tree to improve the efficiency of the determination.4) During the incremental updating process of cadastral database, there should have a set of dynamic operators. so a set of dynamic operators is presented, which map the cadastral entities' spatial changes to it's corresponding object in cadastral database. And the EPL language is used to describe the process of updating.5) Finally, an prototype system is developed using VC++ and COM technology on the platform of ORACLE SPATIAL and MAPINFO 6.5, to examine the methods and models presented in this dissertation. Experimental results with the practical and simulated spatial data show the reasonability and practicability of the incremental updating approach presented in this paper.The author brought forward the issue of incremental updating of cadastral database based on thetopological relationship, and studied the topological relation between cadastral entities, spatial changes' identification of cadastral entities, and the dynamic operators of spatial changes. The proposed approachis operational. The results of this study provide a new way for the design and implementation of suchsystem.