What is the idea behind the non-parametric approach?
To yield greater discrimination, consider replacing the actual counts with their non-parametric ranks, and, for technical reasons, first multiply each rank by 2. The above set would then be transformed to: {3,3,6,8,10,12,14,16,18}. Now, this set is the non-parametric equivalent of the original. The mean is now 10, and there are four units with count smaller than this and four units with count larger. This new set of counts may be used as input to SADIE, exactly as the original counts would have been. With the new set, there are thus four potential patch units and four potential gap units and the ability of the new data to discriminate spatial pattern is therefore enhanced. Note that the arrangement of the original set, defined by the coordinates of its sample units is retained; it is just the counts that are different.
