diff --git a/include/laser/state_block/local_parametrization_polyline_extreme.h b/include/laser/state_block/local_parametrization_polyline_extreme.h
index 7520d63d05c87f80c429055372b69915ab7aaeff..2a2c2340729fd776c22a6ab7d1f6708896860f8d 100644
--- a/include/laser/state_block/local_parametrization_polyline_extreme.h
+++ b/include/laser/state_block/local_parametrization_polyline_extreme.h
@@ -31,6 +31,11 @@ class LocalParametrizationPolylineExtreme : public LocalParametrizationBase
         bool minus(Eigen::Map<const Eigen::VectorXd>& _point1,
                            Eigen::Map<const Eigen::VectorXd>& _point2,
                            Eigen::Map<Eigen::VectorXd>& _delta_theta) override;
+        bool isValid(const Eigen::VectorXd& _state, double tolerance) override
+        {
+            return _state.size() == global_size_;
+        }
+
 };
 
 } // namespace wolf