The Techniques Of Spatial Information Application Based On PDA

It is an emphasis in GIS that researching Embedded GIS and its' application, this paper uses embedded GIS to study spatial information application technology based on PDA.This paper researches GPS locating and navigating technique. It resolves problems of real time receiving and processing of GPS signal, real time displaying GPS location signal, modifying the error of road matching method, the abstraction and construction of the topological structure of city road network, and the shortest path navigation, etc.This paper investigates spatial information queries technique based on the GPS location. It resolves spatial-attributive query and spatial relation queries, and presents a method to judge the simple direction relation by testing which boundary of the reference object's MBR intersects with the link line of two objects. As most of the attributes data of spatial objects are stored in relational database, the paper researches the optimization of the attributive information query, and proposes the principles for optimization of the database design to improve the efficiency of the application's query.This paper implements an embedded GIS application system "Fire Supervised Information Management System". Not only has the system had the functions as the spatial information display, query, and analysis, but also it can provide Location Based Service to users at anytime and anywhere based on mobile platform.