Abstract: This paper introduced research on the methods for two basic geo-spatial-analysis algorithms; getting intersection points for large amounts of segments and point polygon-overlay, and we implemented the two algorithms on the shared memory multi-core environment based on OpenMP. We analyzed the reason why we don't get linear speedup,and got that it is because of unbalanced load and serial memory management method. Then we sorted the input data and adopted the dynamic scheduling of OpenMP. Also, we adopted and improved the current parallel memory allocating technique to manage the memory for parallel algorithms. Based on the two methods above, we improved the algorithms.The tests show that the improved method can reach nearly linear speedup, and the efficiency of each core in a four-core node is above 80%.

Key words: Spatial analysis, Intersection, Point polygon-overlay, Parallel memory allocate