statshorts

In a previous blog post I have talked about "scrambling" geographic point data in an attempt to protect the units, to which these points pertain, from privacy violations. Besides the simple 'random perturbation' discussed there, a whole range of different methods have been suggested. One is Voronoi masking , introduced by Seidl et al. (2015).  Despite the comparatively good capacity of that method to preserve spatial patterns in masked data, its deterministic mechanism raises concerns about the possibility to reverse the procedure, revealing real locations. In this post, I explore the reversal potential of Voronoi geomasking. What is Voronoi masking? Seidl et al. (2015) describe the method (in its most vanilla version) as follows: For each point location, identified by planar geographic coordinates $(x_{i1}, x_{i2})$, its corresponding Voronoi polygon is computed. The point is then shifted onto the closest edge of said polygon along the shortest path. An example is...