Internet GIS System Design And Implementation Of The Underlying Algorithms

Under the background of information society, GIS (Geography Information System) appears as the product of the combination of cartography and computer science. The application of GIS platform has been deep into all works of life, including Power systems, urban construction, transportation, aviation, water conservancy. Modern GIS technology is the result of close combination of traditional GIS, communication and computer network. The developers of different internet applications are trying to add this factor into their own products.The paper constructs a GIS system basic on network in Linux system, connects the geographic information technology supplied by Mapabc Co. under the frame of Qt program design, approaches several existing implementations in measurement and the optimal path algorithm from the underlying, and also the common functions of GIS system.The main algorithms involved in the thesis including the multi-point distance calculation, polygon area calculation, the shortest path and bust routes search function. Among which, multi-point distance calculation, polygon area calculation involves the comparison and implementation of linear model and ellipsoid model algorithm. The research on the optimal path algorithm mainly describe the Dijkstra and Floyd algorithm, which are more commonly used. The characteristics of Dijkstra algorithm is to calculate the shortest path from a node to all other nodes, while the Floyd algorithm is to calculate the distance matrix for all nodes, to get the shortest path from all nodes to all another nodes.The key points in the thesis are the implementations for the above algorithm in the Linux/Qt frame, and the corresponding user interface design. The program is based on the underlying features with highly portability. Making full use of the advantage of sever and network to improve the client experience. The system can supply some services when not connecting with the internet, and even greatly improve the efficiency and function when connecting with the internet.