docs: def gini(self):
          """
          geo.gini()
  
          Return computed Gini coefficient.
          """
          if self.count()>1:
              xsort = sorted(self.raster.data[self.raster.mask == False].flatten()) # increasing order
              y = np.cumsum(xsort)
              B = sum(y) / (y[-1] * len(xsort))
              return 1 + 1./len(xsort) - 2*B
          else:
              return 1