diff --git a/cartographer/mapping/id.h b/cartographer/mapping/id.h
index aa73590..347a243 100644
--- a/cartographer/mapping/id.h
+++ b/cartographer/mapping/id.h
@@ -21,10 +21,12 @@
 #include <iterator>
 #include <limits>
 #include <map>
+#include <memory>
 #include <ostream>
 #include <tuple>
 #include <vector>
 
+#include "cartographer/common/make_unique.h"
 #include "cartographer/common/port.h"
 #include "glog/logging.h"
 
@@ -129,7 +131,7 @@ class MapById {
     using iterator_category = std::bidirectional_iterator_tag;
     using value_type = IdDataReference;
     using difference_type = int64;
-    using pointer = const IdDataReference*;
+    using pointer = std::unique_ptr<const IdDataReference>;
     using reference = const IdDataReference&;
 
     explicit ConstIterator(const MapById& map_by_id, const int trajectory_id)
@@ -149,6 +151,10 @@ class MapById {
           current_data_->second};
     }
 
+    std::unique_ptr<const IdDataReference> operator->() const {
+      return common::make_unique<const IdDataReference>(this->operator*());
+    }
+
     ConstIterator& operator++() {
       CHECK(current_trajectory_ != end_trajectory_);
       ++current_data_;
diff --git a/cartographer/mapping/id_test.cc b/cartographer/mapping/id_test.cc
index 46d448e..7573c7d 100644
--- a/cartographer/mapping/id_test.cc
+++ b/cartographer/mapping/id_test.cc
@@ -41,7 +41,7 @@ TEST(IdTest, MapByIdIterator) {
   map_by_id.Append(42, 3);
   map_by_id.Append(0, 0);
   map_by_id.Append(0, 1);
-  EXPECT_EQ(2, (*map_by_id.BeginOfTrajectory(7)).data);
+  EXPECT_EQ(2, map_by_id.BeginOfTrajectory(7)->data);
   EXPECT_TRUE(std::next(map_by_id.BeginOfTrajectory(7)) ==
               map_by_id.EndOfTrajectory(7));
   std::deque<std::pair<NodeId, int>> expected_id_data = {
diff --git a/cartographer/mapping_2d/sparse_pose_graph.cc b/cartographer/mapping_2d/sparse_pose_graph.cc
index 64a5286..69b2a8e 100644
--- a/cartographer/mapping_2d/sparse_pose_graph.cc
+++ b/cartographer/mapping_2d/sparse_pose_graph.cc
@@ -72,7 +72,7 @@ std::vector<mapping::SubmapId> SparsePoseGraph::GrowSubmapTransformsAsNeeded(
   CHECK_EQ(2, insertion_submaps.size());
   const auto end_it = submap_data.EndOfTrajectory(trajectory_id);
   CHECK(submap_data.BeginOfTrajectory(trajectory_id) != end_it);
-  const mapping::SubmapId last_submap_id = (*std::prev(end_it)).id;
+  const mapping::SubmapId last_submap_id = std::prev(end_it)->id;
   if (submap_data_.at(last_submap_id).submap == insertion_submaps.front()) {
     // In this case, 'last_submap_id' is the ID of 'insertions_submaps.front()'
     // and 'insertions_submaps.back()' is new.
@@ -596,7 +596,7 @@ transform::Rigid3d SparsePoseGraph::ComputeLocalToGlobalTransform(
   if (begin_it == end_it) {
     return transform::Rigid3d::Identity();
   }
-  const mapping::SubmapId last_optimized_submap_id = (*std::prev(end_it)).id;
+  const mapping::SubmapId last_optimized_submap_id = std::prev(end_it)->id;
   // Accessing 'local_pose' in Submap is okay, since the member is const.
   return transform::Embed3D(
              submap_transforms.at(last_optimized_submap_id).pose) *