private function getCellHeight($x, $y, $stepSize = 0)
    {
        try {
            return $this->terra[$x][$y];
        } catch (Exception $e) {
            return $this->getOffset($stepSize);
        }
    }
private function getCellHeight($x, $y, $stepSize = 0)
    {
        try {
            return $this->terra[$x][$y];
        } catch (Exception $e) {
            return $this->getOffset($stepSize);
        }
    }
private function getCellHeight ( $ x , $ y , $ stepSize = 0 ) { try { return $ this -> terra [ $ x ] [ $ y ] ; } catch ( Exception $ e ) { return $ this -> getOffset ( $ stepSize ) ; } }
return point height if point exists, else random height

@param $x
@param $y
@param $stepSize

@return double
return point height if point exists else random height