Description
Direct and linear Normal score transformations do not support datasets where some values have declustering weights of zero. This situation occurs when polygonal declustering (Voronoi polygons) is used with the clipping polygon option and some data points are left outside the clipping polygon.
Solution
There are two options to solve the problem: for polygon declustering, change the clipping polygon so that all points are included, or use Gaussian kernels for the normal score transformation; use cell declustering instead of polygon declustering. Declustering can only be performed in ArcMap 10.3 or earlier.