Network Of Geographic Information Systems Research And Development,

The System adopts spatial data model based on the vector data model; topology relation model uses spatial data model combined with spatial data index; and makes use of relation database to save spatial entity data. UML technology is employed to design and layout the system structure. The object-oriented technology plies the Microsoft Visual C++ 6.0 to develop the software. The spatial data index betakes the spatial data structure based on the improved R-Tree structure, and the property index uses the B+ tree data structure. Network data transportation adopts the three-level frame model, and uses Java Applet to exploit the network part.The whole system gets definite production and evident effect, but it still needs long time to develop the system and in-depth exploitation and improvement.