I also thought about that. Unfortunately the type used in distance map is a part of the public interface of the class, because there is a function [getDistanceMap](http://docs.pointclouds.org/trunk/classpcl_1_1_integral_image_normal_estimation.html#a84ba79488f0068c287293f08a90c5720). I doubt that anyone actually uses it, but taking into account that the benefits of switching to int are negligible, I though it is better not to touch it.