SDBE: The Research And Implementation Of The Spatial Operations

Spatial analysis is the basic applicational requirements of geographic information system, and it is also the important function that distinguishes geographic information systems from other management information systems. For GIS, users usually have the request to analyse and query some spatial data according to their different application requirements.Spatial operation is the basis of spatial analysis. In GIS, there need to determine the geometric shape of the spatial objects and the spatial relationships between them as well as to synthesize the spatial objects for high-level analysis. Apparently, spatial operation is a very important part of GIS. It will support the GIS application development strongly and make the implemention of spatial analysis and operation more efficient if we can offer the basic spatial operation functions.The basic operations in spatial operations are line intersection operation and the spatial synthetic operation for closed set polygons in the plane, so this dissertation will put the emphasis on the algorithms and their implementations of these two operations.For line intersection algorithm, the dissertation introduces several existing algorithms and compares their efficiency, space usage, implementation complication and extensibility. Then it describes author's implementation of the line intersection algorithm. For the spatial synthetic operations algorithms about the closed set of polygons in the plane, this dissertation discusses the theory of the implementation and processing rules of each step in detail. Finally, it analyses the system performances and points out the directions for further improvements.