Key Technical Research On Vector-Raster Mixed Map Based On The Smart Phone

Recently, with the rapid improvement of the performance of the smart phone and the increasing range of applications based on Embedded GIS, the requirements for map showing based on smart phone is increasing correspondingly.Among those existing map-showing methods, the deploying of raster map is one of the most outstanding saluting and has been used more and more widely due to its unique advantages of rich information and exquisite sight. However, as a result of its lack in supporting network space analysis, the raster map needs to be integrated with vector map in order to satisfy the map-showing requirements with Vector-Rater mixed mode. Therefore, the design and implement of the Vector-Raster mixed map has attracted more and more research effort in recent years.In this paper, we propose a novel solution for deploying Vector-Rater mixed map on smart phone as well as discuss some key technical issues as follows:the organization of the data, the data storage and dissemination scheme, the rendering of the Vector-Raster mixed map and so on. The organization of the vector data is partition and layer, while the raster data is tile-pyramid model using file storage; In order to settle the cache replacement problems of pyramid structure of raster data, we propose a novel algorithm, named P-LRU, which relate to the layers of the pyramid; Based on the characteristic of the Vector-Raster mixed map, we also provide the strategy based on the routing results; For the purpose of efficiently and correctly rendering Vector-Raster mixed map, the raster map is used as the base map while the vector map is the overlay. Finally, we summarize our work and point out the direction of future research in the topic of developing Vector-Raster mixed map on the smart phone.