code: def absrange_fltr(dem, rangelim):
      
      out = range_fltr(np.ma.abs(dem), *rangelim)
      #Apply mask to original input
      out = np.ma.array(dem, mask=np.ma.getmaskarray(out))
      out.set_fill_value(dem.fill_value)
      return out
docs: Absolute range filter