Fast and Robust Point-in-Spherical-Polygon Tests Using Multilevel Spherical Grids
Point-in-spherical-polygon determination is widely required in applications over the earth. However, existing methods for point-in-polygon tests cannot be applied directly, due to non-Euclidean computation over the spherical surface. Thus, it is general to transform a spherical polygon into a planar polygon via projection, and then perform point-in-polygon tests. Unfortunately, this is expensive and may cause determination errors. In this paper, we propose to subdivide the spherical grid cells iteratively, and apply the ray-crossing method locally in grid cells, which is by one of our previous works. As a result, this not only avoids expensive transformation computation, but also guarantees robust determination for point-in-spherical-polygon tests. Experimental results attest our effectiveness, and show an acceleration of five orders of magnitude over a popularly used method.
KeywordsPoint-in-spherical-polygon test Multilevel grid Ray-crossing
This work is partially supported by the sub-project of the National Key Research and Development Program of China (No. 2016QY01W0101), the National Natural Science Foundation of China (Nos. 60873182, 61379087, U1435220, and 61661146002), and the EU FP7 funded project AniNex (FP7-IRSES-612627).
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