earticle

영어

Visibility research, calculating LOS and viewshed is one of the most important paradigms of the GIS. As increasingly large-scale data have become available the volume of these datasets reveals scalability problems with existing GIS algorithms. To solve this problem, a kind of serial algorithm was developed to generate viewshed on large DEMs. This paper divided the whole DEM into rectangular blocks in row and column directions, the processed these blocks with four axes followed by four sectors sequentially for selection of LCPs Using viewsheds analysis. When processing the particular block, we use the reference plane method to calculate the visibility of the target point on the block, and adjusted the calculation sequence according to the different spatial relationships between the block and the viewpoint since the viewpoint is not always inside the DEM. By using reference Plane method and using a block partitioning method to segment and load the DEM dynamically, it is possible to analysis viewshed efficiently. Experiments showed that overcome the limit of commercial GIS software and suggested retains the accuracy of the reference plane method and has near linear computer complexity.