Research And Implement Of Spatial Index Of Mobile GIS Based On Smart Phone

Integrating various technologies including mobile communication technology, global positioning technology, Internet technology and other technical support in the mobile computing environment, Mobile GIS is a highly concentrated, highly streamlined GIS software system. Mobility and real time are the most important feature of mobile GIS. So the key technology is how to ensure rapid response mechanism of Mobile GIS. As one of the key techniques of Mobile GIS, spatial index technology is the core of the whole system, its performance will directly affect the efficiency of storage of spatial data and performance of spatial retrieval and it's also related to the overall performance of Mobile GIS. Therefore, the study of mobile GIS spatial index that is suitable to mobile smart devices is becoming one of the important subjects in the field of mobile GIS technology.Firstly, the paper describes the basic theory of spatial index of mobile GIS, and classifies spatial index by index region and principles of object segmentation, then makes a detailed analysis and comparison of the spatial index structure principle and operation algorithms, including the index structure, building index, operating algorithm, algorithm performance and other aspects, last points out the characteristics and problems of spatial index. This paper puts forward the improved algorithm of spatial index and design thoughts.Secondly, According to the characteristics of data model under the platform of mobile GIS and basic theory of the existing spatial index, the paper brings up a new spatial structure—DOQR tree which dynamically divides space index ; then describes the structure of the DOQR tree and insert, query, delete, update and other spatial index operations in detail. Using C + + OOP design spatial index interface class, ISpataialIndex class and DOQR class; takes the spatial index into an Independent developed mobile GIS software "MiniGIS", and tests the simulation data and real geographic data in the smart phone. By comparing and analysing all performance on Mobile GIS, it shows that DOQR tree has a high efficiency of constructing and retrieving than general Quadtree and classical R tree.While researching the spatial index theory, the mobile GIS is designed and implemented under the environment of Embedded Visua C++4.0. Based on this system, the architecture of mobile GIS and key technologies are introduced in this paper. Then, DOQR tree is successfully applied to the mobile GIS system.Based on the above researches, mobile GIS applied in digital city grids management is discussed in this paper. Then, the prototype system of MiniGIS is professionally customized to be the digital patrol system.Last, taking campus digital patrol system for example, work processed of the patrol system are introduced in detail. Experiments show that mobile GIS integrated with DOQR tree in digital patrol system can full play its advantages and improve system performance.