private Vector3 middleOfCell(int x_index, int y_index) {
        float middleXCell = (float) (indexRegion.minX() + x_index * x_size + x_size / 2);
        float middleYCell = (float) (indexRegion.minY() + y_index * y_size + y_size / 2);
        return new Vector3(middleXCell, middleYCell, 0);
    }
private Vector3 middleOfCell ( int x_index , int y_index ) { float middleXCell = ( float ) ( indexRegion . minX ( ) + x_index * x_size + x_size / 2 ) ; float middleYCell = ( float ) ( indexRegion . minY ( ) + y_index * y_size + y_size / 2 ) ; return new Vector3 ( middleXCell , middleYCell , 0 ) ; }
Create a point at the center of a cell

@param x_index horizontal cell index
@param y_index vertical cell index
@return Point at the center of the cell at (x_index, y_index)