From 5d784e8adbb5ab1f2cbb26f0b8b197734561713a Mon Sep 17 00:00:00 2001
From: Wolfgang Hess <whess@google.com>
Date: Thu, 19 Oct 2017 16:58:07 +0200
Subject: [PATCH] Prepare for googlecartographer/cartographer#605. (#551)

---
 cartographer_ros/cartographer_ros/map_builder_bridge.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/cartographer_ros/cartographer_ros/map_builder_bridge.cc b/cartographer_ros/cartographer_ros/map_builder_bridge.cc
index c811692..3fc7aa5 100644
--- a/cartographer_ros/cartographer_ros/map_builder_bridge.cc
+++ b/cartographer_ros/cartographer_ros/map_builder_bridge.cc
@@ -171,6 +171,9 @@ MapBuilderBridge::GetTrajectoryStates() {
 
     const cartographer::mapping::TrajectoryBuilder* const trajectory_builder =
         map_builder_.GetTrajectoryBuilder(trajectory_id);
+    if (trajectory_builder == nullptr) {
+      continue;
+    }
     const cartographer::mapping::TrajectoryBuilder::PoseEstimate pose_estimate =
         trajectory_builder->pose_estimate();
     if (cartographer::common::ToUniversal(pose_estimate.time) < 0) {