Naive implementation of the Voronoi-Based K Nearest Neighbor Algorithm using Graphast framework.
Based on Kolahdouzan, Mohammad, and Cyrus Shahabi. "Voronoi-based k nearest neighbor search for spatial network databases." Proceedings of the Thirtieth international conference on Very large data bases-Volume 30. VLDB Endowment, 2004.]
In this implementation, border points are no shared by adjacent polygons. Instead, an edge connect them.
The current version is not using a R-Tree index to find the first nearest neighbor. In the pre-processing step we creat a Map structure to store this kind of information. Should be improved in the comming versions.