  The generic number of critical points of the Euclidean distance function from
a data point to a variety is called the Euclidean distance degree. The two
special loci of the data points where the number of critical points is smaller
then the ED degree are called the Euclidean Distance Data Singular Locus and
the Euclidean Distance Data Isotropic Locus. In this article we present
connections between these two special loci of an affine cone and its dual cone.
