Study On Spatial Geographic Data Organization In Embedded GIS

With the rapid development and widespread application of Embedded, GIS and Satellite positioning technology, Embedded Geographic Information System has become one of the hottest research issues in many fields such as computer science and surveying and mapping.As the kernel and basis of Embedded GIS, spatial geographic data has the widespread application. After integrated access, storage and real-time dynamic management, allocation, display, query and analysis, the various types of spatial geographic data have been combined with other application unit as a whole.At the same time, the development of embedded GIS is still at its early stage, and faced with some difficulties, such as limited hardware resources, complex spatial geographic data, massive data, and delay of electronic map refreshing. Such a series of problems need to be studied and resolved with special technology.This paper particularly studies how to express, organize, dispatch and display spatial geographic data in order to overcome the shortages of current embedded GIS research.After analyzed the constraint sets of spatial geographic data organization in embedded GIS, some new data organization strategies based on the complexity of constraints are proposed, which resolve the conflict between system resources and real-time requirement of computation of embedded GIS. Based on these strategies, a new model framework for data organization is proposed. In this model framework, spatial geographic data organization is divided into two parts: data preprocess and data organization realization.For the characteristic of the spatial geographic date, data preprocess in the desktop environment is proposed. In this preprocess, all kinds of original vector spatial geographic data can be transferred to uniform data format, which suits with embedded GIS. Various strategies and algorithms using in spatial geographic data preprocess are proposed and implemented, the primary working flow includes data collation, generation, encryption and load. Thus can guarantee safely and effectively to organize, dispatch and management spatial geographic data.Based on the data preprocess, this paper studies mechanism of data organization realization of embedded GIS, and put emphasis upon the study of the real-time display of electronic map. A new parallel display algorithm PMDR using multi-buffers is proposed and implemented. The PMDR algorithm can effectively use the hardware resources, dynamically index and dispatch spatial geographic data, so that realizes the real-time and dynamic display of electronic map. Experiments show that the algorithm achieves more reasonable screen display layout, reduces the refreshing respond time, and makes the display more rapidly and smoothly. Therefore, the realization mechanism validates the rationality and efficiency of data organization and scheduling.