GuanTestGrid            Nonparametric Test of Isotropy Using the Sample
                        Semivariogram
GuanTestUnif            Nonparametric Test of Isotropy Using the Sample
                        Semivariogram
LuTest                  Nonparametric Test of Symmetry Using the
                        Periodogram
MaityTest               Nonparametric Test of Isotropy Using the Sample
                        Covariogram
coords.aniso            Geometric Anisotropy Correction from geoR
spTest                  Nonparametric Hypothesis Tests of Isotropy and
                        Symmetry
