ui/src/main/java/ucar/nc2/ui/gis/SpatialGrid.java
private double distanceSq( Point2D pt, int indexX, int indexY) {
    if ((indexX < 0) || (indexX >= countX) || (indexY < 0) || (indexY >= countY)) // outside bounding box
      return MAX_DOUBLE;

      GridCell gtest = gridArray[indexY][indexX];
      if (!gtest.used)    // nothing in this cell
        return MAX_DOUBLE;

        // get distance from center of cell
      Rectangle2D rect = gtest.objectBB;
      double dx = rect.getX()+rect.getWidth()/2 - pt.getX();
      double dy = rect.getY()+rect.getHeight()/2 - pt.getY();
      return (dx*dx + dy*dy);
    }
private double distanceSq( Point2D pt, int indexX, int indexY) {
    if ((indexX < 0) || (indexX >= countX) || (indexY < 0) || (indexY >= countY)) // outside bounding box
      return MAX_DOUBLE;

      GridCell gtest = gridArray[indexY][indexX];
      if (!gtest.used)    // nothing in this cell
        return MAX_DOUBLE;

        // get distance from center of cell
      Rectangle2D rect = gtest.objectBB;
      double dx = rect.getX()+rect.getWidth()/2 - pt.getX();
      double dy = rect.getY()+rect.getHeight()/2 - pt.getY();
      return (dx*dx + dy*dy);
    }
if out of bbox or cell not marked, return MAX_DOUBLE