diff --git a/cartographer/mapping/2d/submap_2d.cc b/cartographer/mapping/2d/submap_2d.cc
index 5a52074..63aff81 100644
--- a/cartographer/mapping/2d/submap_2d.cc
+++ b/cartographer/mapping/2d/submap_2d.cc
@@ -137,8 +137,6 @@ std::vector<std::shared_ptr<Submap2D>> ActiveSubmaps2D::submaps() const {
   return submaps_;
 }
 
-int ActiveSubmaps2D::matching_index() const { return matching_submap_index_; }
-
 void ActiveSubmaps2D::InsertRangeData(const sensor::RangeData& range_data) {
   for (auto& submap : submaps_) {
     submap->InsertRangeData(range_data, range_data_inserter_.get());
@@ -169,7 +167,6 @@ std::unique_ptr<GridInterface> ActiveSubmaps2D::CreateGrid(
 void ActiveSubmaps2D::FinishSubmap() {
   Submap2D* submap = submaps_.front().get();
   submap->Finish();
-  ++matching_submap_index_;
   submaps_.erase(submaps_.begin());
 }
 
@@ -183,7 +180,6 @@ void ActiveSubmaps2D::AddSubmap(const Eigen::Vector2f& origin) {
   submaps_.push_back(common::make_unique<Submap2D>(
       origin, std::unique_ptr<Grid2D>(
                   static_cast<Grid2D*>(CreateGrid(origin).release()))));
-  LOG(INFO) << "Added submap " << matching_submap_index_ + submaps_.size();
 }
 
 }  // namespace mapping
diff --git a/cartographer/mapping/2d/submap_2d.h b/cartographer/mapping/2d/submap_2d.h
index 8a58de3..a02b3ef 100644
--- a/cartographer/mapping/2d/submap_2d.h
+++ b/cartographer/mapping/2d/submap_2d.h
@@ -79,10 +79,6 @@ class ActiveSubmaps2D {
   ActiveSubmaps2D(const ActiveSubmaps2D&) = delete;
   ActiveSubmaps2D& operator=(const ActiveSubmaps2D&) = delete;
 
-  // Returns the index of the newest initialized Submap which can be
-  // used for scan-to-map matching.
-  int matching_index() const;
-
   // Inserts 'range_data' into the Submap collection.
   void InsertRangeData(const sensor::RangeData& range_data);
 
@@ -95,7 +91,6 @@ class ActiveSubmaps2D {
   void AddSubmap(const Eigen::Vector2f& origin);
 
   const proto::SubmapsOptions2D options_;
-  int matching_submap_index_ = 0;
   std::vector<std::shared_ptr<Submap2D>> submaps_;
   std::unique_ptr<RangeDataInserterInterface> range_data_inserter_;
 };
diff --git a/cartographer/mapping/2d/submap_2d_test.cc b/cartographer/mapping/2d/submap_2d_test.cc
index c662b16..62266e9 100644
--- a/cartographer/mapping/2d/submap_2d_test.cc
+++ b/cartographer/mapping/2d/submap_2d_test.cc
@@ -61,10 +61,11 @@ TEST(Submap2DTest, TheRightNumberOfRangeDataAreInserted) {
     for (const auto& submap : submaps.submaps()) {
       all_submaps.insert(submap);
     }
-    if (submaps.matching_index() != 0) {
+    if (submaps.submaps().size() > 1) {
       EXPECT_LE(kNumRangeData, submaps.submaps().front()->num_range_data());
     }
   }
+  EXPECT_EQ(2, submaps.submaps().size());
   int correct_num_range_data = 0;
   for (const auto& submap : all_submaps) {
     if (submap->num_range_data() == kNumRangeData * 2) {
diff --git a/cartographer/mapping/3d/submap_3d.cc b/cartographer/mapping/3d/submap_3d.cc
index cb5709d..b2c4b6e 100644
--- a/cartographer/mapping/3d/submap_3d.cc
+++ b/cartographer/mapping/3d/submap_3d.cc
@@ -294,8 +294,6 @@ std::vector<std::shared_ptr<Submap3D>> ActiveSubmaps3D::submaps() const {
   return submaps_;
 }
 
-int ActiveSubmaps3D::matching_index() const { return matching_submap_index_; }
-
 void ActiveSubmaps3D::InsertRangeData(
     const sensor::RangeData& range_data,
     const Eigen::Quaterniond& gravity_alignment) {
@@ -312,13 +310,11 @@ void ActiveSubmaps3D::InsertRangeData(
 void ActiveSubmaps3D::AddSubmap(const transform::Rigid3d& local_submap_pose) {
   if (submaps_.size() > 1) {
     submaps_.front()->Finish();
-    ++matching_submap_index_;
     submaps_.erase(submaps_.begin());
   }
   submaps_.emplace_back(new Submap3D(options_.high_resolution(),
                                      options_.low_resolution(),
                                      local_submap_pose));
-  LOG(INFO) << "Added submap " << matching_submap_index_ + submaps_.size();
 }
 
 }  // namespace mapping
diff --git a/cartographer/mapping/3d/submap_3d.h b/cartographer/mapping/3d/submap_3d.h
index fd6b8f0..3d18236 100644
--- a/cartographer/mapping/3d/submap_3d.h
+++ b/cartographer/mapping/3d/submap_3d.h
@@ -88,10 +88,6 @@ class ActiveSubmaps3D {
   ActiveSubmaps3D(const ActiveSubmaps3D&) = delete;
   ActiveSubmaps3D& operator=(const ActiveSubmaps3D&) = delete;
 
-  // Returns the index of the newest initialized Submap which can be
-  // used for scan-to-map matching.
-  int matching_index() const;
-
   // Inserts 'range_data' into the Submap collection. 'gravity_alignment' is
   // used for the orientation of new submaps so that the z axis approximately
   // aligns with gravity.
diff --git a/cartographer/mapping/internal/2d/pose_graph_2d.cc b/cartographer/mapping/internal/2d/pose_graph_2d.cc
index 141c646..7982d08 100644
--- a/cartographer/mapping/internal/2d/pose_graph_2d.cc
+++ b/cartographer/mapping/internal/2d/pose_graph_2d.cc
@@ -131,6 +131,7 @@ NodeId PoseGraph2D::AddNode(
     const SubmapId submap_id =
         data_.submap_data.Append(trajectory_id, InternalSubmapData());
     data_.submap_data.at(submap_id).submap = insertion_submaps.back();
+    LOG(INFO) << "Inserted submap " << submap_id << ".";
   }
 
   // We have to check this here, because it might have changed by the time we
diff --git a/cartographer/mapping/internal/3d/pose_graph_3d.cc b/cartographer/mapping/internal/3d/pose_graph_3d.cc
index b5aa5a6..e29b193 100644
--- a/cartographer/mapping/internal/3d/pose_graph_3d.cc
+++ b/cartographer/mapping/internal/3d/pose_graph_3d.cc
@@ -129,6 +129,7 @@ NodeId PoseGraph3D::AddNode(
     const SubmapId submap_id =
         data_.submap_data.Append(trajectory_id, InternalSubmapData());
     data_.submap_data.at(submap_id).submap = insertion_submaps.back();
+    LOG(INFO) << "Inserted submap " << submap_id << ".";
   }
 
   // We have to check this here, because it might have changed by the time we