Jianting Zhang
Jianting Zhang
Python demo code is under python/cuspatial/demos. They were mostly developed last summer and are outdated. Some of these demos can not run out-of-box anyway as they rely on external data....
There are very informative discussions on the ordering of polygon vertices: https://gis.stackexchange.com/questions/119150/order-of-polygon-vertices-in-general-gis-clockwise-or-counterclockwise The OGC SFS and ESRI shapefile have different orderings. As long as the inner rings and the outer...
The Shapefile Reader API does have a problem in dealing with multi-polygons. The initial design was to break multi-polygons (as well as GeometryCollection) into multiple (single/regular) polygons (with or without...
There is a simple way to determine the orientation of a ring/curve, e.g., signed area. https://en.wikipedia.org/wiki/Curve_orientation Also https://stackoverflow.com/questions/1165647/how-to-determine-if-a-list-of-polygon-points-are-in-clockwise-order It actually might be useful to return the area of rings for...
@Norticaranda I just tested the indexing/join modules on NYC taxi trip data. See the test code at https://github.com/zhangjianting/cuspatial/blob/fea-quadtree-indexing/cpp/tests/join/spatial_join_nyctaxi_test.cu. The results have been partially verified by maual inspection. The indexing/join implementations...
Just a comment from application perspective: while Hausdorff distance matrix can be used as the input of clustering algorithms to group trajectories, it would be a little difficult to figure...
For test, I would suggest verify polygon-polygon distance result by comparing against libgeos result, as that would be the what geospaital community expects.
Sorry that I missed @thomcom comment. This function was a CUDA port of a Java function for Intelligent Transportation applications using surveillance cameras. I do not fully understand the algorithm...
I think the "old" point-in-polygon test API is still useful when the number of polygons is small for two reasons: 1) no need for indexing on points which could be...
@DeoLeung Thanks for your interests in cuSpatial. Currently we are busy with spatial indexing and indexed spatial join. Hopefully we will have time to revisit spatial window queries using the...