diff --git a/cartographer/mapping/global_trajectory_builder.h b/cartographer/mapping/global_trajectory_builder.h
index ec04469..acc206d 100644
--- a/cartographer/mapping/global_trajectory_builder.h
+++ b/cartographer/mapping/global_trajectory_builder.h
@@ -25,16 +25,16 @@ namespace cartographer {
 namespace mapping {
 
 template <typename LocalTrajectoryBuilder,
-          typename LocalTrajectoryBuilderOptions, typename SparsePoseGraph>
+          typename LocalTrajectoryBuilderOptions, typename PoseGraph>
 class GlobalTrajectoryBuilder
     : public mapping::GlobalTrajectoryBuilderInterface {
  public:
   GlobalTrajectoryBuilder(
       const LocalTrajectoryBuilderOptions& options, const int trajectory_id,
-      SparsePoseGraph* const sparse_pose_graph,
+      PoseGraph* const pose_graph,
       const LocalSlamResultCallback& local_slam_result_callback)
       : trajectory_id_(trajectory_id),
-        sparse_pose_graph_(sparse_pose_graph),
+        pose_graph_(pose_graph),
         local_trajectory_builder_(options),
         local_slam_result_callback_(local_slam_result_callback) {}
   ~GlobalTrajectoryBuilder() override {}
@@ -59,7 +59,7 @@ class GlobalTrajectoryBuilder
     std::unique_ptr<mapping::NodeId> node_id;
     if (matching_result->insertion_result != nullptr) {
       node_id = ::cartographer::common::make_unique<mapping::NodeId>(
-          sparse_pose_graph_->AddNode(
+          pose_graph_->AddNode(
               matching_result->insertion_result->constant_data, trajectory_id_,
               matching_result->insertion_result->insertion_submaps));
       CHECK_EQ(node_id->trajectory_id, trajectory_id_);
@@ -73,24 +73,24 @@ class GlobalTrajectoryBuilder
 
   void AddSensorData(const sensor::ImuData& imu_data) override {
     local_trajectory_builder_.AddImuData(imu_data);
-    sparse_pose_graph_->AddImuData(trajectory_id_, imu_data);
+    pose_graph_->AddImuData(trajectory_id_, imu_data);
   }
 
   void AddSensorData(const sensor::OdometryData& odometry_data) override {
     CHECK(odometry_data.pose.IsValid()) << odometry_data.pose;
     local_trajectory_builder_.AddOdometryData(odometry_data);
-    sparse_pose_graph_->AddOdometryData(trajectory_id_, odometry_data);
+    pose_graph_->AddOdometryData(trajectory_id_, odometry_data);
   }
 
   void AddSensorData(
       const sensor::FixedFramePoseData& fixed_frame_pose) override {
     CHECK(fixed_frame_pose.pose.IsValid()) << fixed_frame_pose.pose;
-    sparse_pose_graph_->AddFixedFramePoseData(trajectory_id_, fixed_frame_pose);
+    pose_graph_->AddFixedFramePoseData(trajectory_id_, fixed_frame_pose);
   }
 
  private:
   const int trajectory_id_;
-  SparsePoseGraph* const sparse_pose_graph_;
+  PoseGraph* const pose_graph_;
   LocalTrajectoryBuilder local_trajectory_builder_;
   LocalSlamResultCallback local_slam_result_callback_;
 };
diff --git a/cartographer/mapping/map_builder.cc b/cartographer/mapping/map_builder.cc
index 70860d6..f19bf1a 100644
--- a/cartographer/mapping/map_builder.cc
+++ b/cartographer/mapping/map_builder.cc
@@ -62,12 +62,12 @@ MapBuilder::MapBuilder(
   if (options.use_trajectory_builder_2d()) {
     sparse_pose_graph_2d_ = common::make_unique<mapping_2d::SparsePoseGraph>(
         options_.sparse_pose_graph_options(), &thread_pool_);
-    sparse_pose_graph_ = sparse_pose_graph_2d_.get();
+    pose_graph_ = sparse_pose_graph_2d_.get();
   }
   if (options.use_trajectory_builder_3d()) {
     sparse_pose_graph_3d_ = common::make_unique<mapping_3d::SparsePoseGraph>(
         options_.sparse_pose_graph_options(), &thread_pool_);
-    sparse_pose_graph_ = sparse_pose_graph_3d_.get();
+    pose_graph_ = sparse_pose_graph_3d_.get();
   }
 }
 
@@ -104,13 +104,13 @@ int MapBuilder::AddTrajectoryBuilder(
   }
   if (trajectory_options.pure_localization()) {
     constexpr int kSubmapsToKeep = 3;
-    sparse_pose_graph_->AddTrimmer(common::make_unique<PureLocalizationTrimmer>(
+    pose_graph_->AddTrimmer(common::make_unique<PureLocalizationTrimmer>(
         trajectory_id, kSubmapsToKeep));
   }
   if (trajectory_options.has_initial_trajectory_pose()) {
     const auto& initial_trajectory_pose =
         trajectory_options.initial_trajectory_pose();
-    sparse_pose_graph_->SetInitialTrajectoryPose(
+    pose_graph_->SetInitialTrajectoryPose(
         trajectory_id, initial_trajectory_pose.to_trajectory_id(),
         transform::ToRigid3(initial_trajectory_pose.relative_pose()),
         common::FromUniversal(initial_trajectory_pose.timestamp()));
@@ -131,7 +131,7 @@ TrajectoryBuilder* MapBuilder::GetTrajectoryBuilder(
 
 void MapBuilder::FinishTrajectory(const int trajectory_id) {
   sensor_collator_.FinishTrajectory(trajectory_id);
-  sparse_pose_graph_->FinishTrajectory(trajectory_id);
+  pose_graph_->FinishTrajectory(trajectory_id);
 }
 
 int MapBuilder::GetBlockingTrajectoryId() const {
@@ -148,7 +148,7 @@ std::string MapBuilder::SubmapToProto(
            std::to_string(num_trajectory_builders()) + " trajectories.";
   }
 
-  const auto submap_data = sparse_pose_graph_->GetSubmapData(submap_id);
+  const auto submap_data = pose_graph_->GetSubmapData(submap_id);
   if (submap_data.submap == nullptr) {
     return "Requested submap " + std::to_string(submap_id.submap_index) +
            " from trajectory " + std::to_string(submap_id.trajectory_id) +
@@ -160,10 +160,10 @@ std::string MapBuilder::SubmapToProto(
 
 void MapBuilder::SerializeState(io::ProtoStreamWriter* const writer) {
   // We serialize the pose graph followed by all the data referenced in it.
-  writer->WriteProto(sparse_pose_graph_->ToProto());
+  writer->WriteProto(pose_graph_->ToProto());
   // Next we serialize all submap data.
   {
-    for (const auto& submap_id_data : sparse_pose_graph_->GetAllSubmapData()) {
+    for (const auto& submap_id_data : pose_graph_->GetAllSubmapData()) {
       proto::SerializedData proto;
       auto* const submap_proto = proto.mutable_submap();
       submap_proto->mutable_submap_id()->set_trajectory_id(
@@ -176,7 +176,7 @@ void MapBuilder::SerializeState(io::ProtoStreamWriter* const writer) {
   }
   // Next we serialize all node data.
   {
-    for (const auto& node_id_data : sparse_pose_graph_->GetTrajectoryNodes()) {
+    for (const auto& node_id_data : pose_graph_->GetTrajectoryNodes()) {
       proto::SerializedData proto;
       auto* const node_proto = proto.mutable_node();
       node_proto->mutable_node_id()->set_trajectory_id(
@@ -189,7 +189,7 @@ void MapBuilder::SerializeState(io::ProtoStreamWriter* const writer) {
   }
   // Next we serialize IMU data from the pose graph.
   {
-    const auto all_imu_data = sparse_pose_graph_->GetImuData();
+    const auto all_imu_data = pose_graph_->GetImuData();
     for (const int trajectory_id : all_imu_data.trajectory_ids()) {
       for (const auto& imu_data : all_imu_data.trajectory(trajectory_id)) {
         proto::SerializedData proto;
@@ -202,7 +202,7 @@ void MapBuilder::SerializeState(io::ProtoStreamWriter* const writer) {
   }
   // Next we serialize odometry data from the pose graph.
   {
-    const auto all_odometry_data = sparse_pose_graph_->GetOdometryData();
+    const auto all_odometry_data = pose_graph_->GetOdometryData();
     for (const int trajectory_id : all_odometry_data.trajectory_ids()) {
       for (const auto& odometry_data :
            all_odometry_data.trajectory(trajectory_id)) {
@@ -230,7 +230,7 @@ void MapBuilder::LoadMap(io::ProtoStreamReader* const reader) {
               .second)
         << "Duplicate trajectory ID: " << trajectory_proto.trajectory_id();
     trajectory_proto.set_trajectory_id(new_trajectory_id);
-    sparse_pose_graph_->FreezeTrajectory(new_trajectory_id);
+    pose_graph_->FreezeTrajectory(new_trajectory_id);
   }
 
   MapById<SubmapId, transform::Rigid3d> submap_poses;
@@ -263,7 +263,7 @@ void MapBuilder::LoadMap(io::ProtoStreamReader* const reader) {
       const transform::Rigid3d node_pose =
           node_poses.at(NodeId{proto.node().node_id().trajectory_id(),
                                proto.node().node_id().node_index()});
-      sparse_pose_graph_->AddNodeFromProto(node_pose, proto.node());
+      pose_graph_->AddNodeFromProto(node_pose, proto.node());
     }
     if (proto.has_submap()) {
       proto.mutable_submap()->mutable_submap_id()->set_trajectory_id(
@@ -271,7 +271,7 @@ void MapBuilder::LoadMap(io::ProtoStreamReader* const reader) {
       const transform::Rigid3d submap_pose =
           submap_poses.at(SubmapId{proto.submap().submap_id().trajectory_id(),
                                    proto.submap().submap_id().submap_index()});
-      sparse_pose_graph_->AddSubmapFromProto(submap_pose, proto.submap());
+      pose_graph_->AddSubmapFromProto(submap_pose, proto.submap());
     }
     // TODO(ojura): Deserialize IMU and odometry data when loading unfrozen
     // trajectories.
@@ -290,7 +290,7 @@ void MapBuilder::LoadMap(io::ProtoStreamReader* const reader) {
     const SubmapId submap_id{
         trajectory_remapping.at(constraint_proto.submap_id().trajectory_id()),
         constraint_proto.submap_id().submap_index()};
-    sparse_pose_graph_->AddNodeToSubmap(node_id, submap_id);
+    pose_graph_->AddNodeToSubmap(node_id, submap_id);
   }
   CHECK(reader->eof());
 }
@@ -299,7 +299,7 @@ int MapBuilder::num_trajectory_builders() const {
   return trajectory_builders_.size();
 }
 
-SparsePoseGraph* MapBuilder::sparse_pose_graph() { return sparse_pose_graph_; }
+PoseGraph* MapBuilder::pose_graph() { return pose_graph_; }
 
 }  // namespace mapping
 }  // namespace cartographer
diff --git a/cartographer/mapping/map_builder.h b/cartographer/mapping/map_builder.h
index a42b316..e5b5d35 100644
--- a/cartographer/mapping/map_builder.h
+++ b/cartographer/mapping/map_builder.h
@@ -29,10 +29,10 @@
 #include "cartographer/common/thread_pool.h"
 #include "cartographer/io/proto_stream.h"
 #include "cartographer/mapping/id.h"
+#include "cartographer/mapping/pose_graph.h"
 #include "cartographer/mapping/proto/map_builder_options.pb.h"
 #include "cartographer/mapping/proto/submap_visualization.pb.h"
 #include "cartographer/mapping/proto/trajectory_builder_options.pb.h"
-#include "cartographer/mapping/sparse_pose_graph.h"
 #include "cartographer/mapping/submaps.h"
 #include "cartographer/mapping/trajectory_builder.h"
 #include "cartographer/mapping_2d/sparse_pose_graph.h"
@@ -46,7 +46,7 @@ proto::MapBuilderOptions CreateMapBuilderOptions(
     common::LuaParameterDictionary* const parameter_dictionary);
 
 // Wires up the complete SLAM stack with TrajectoryBuilders (for local submaps)
-// and a SparsePoseGraph for loop closure.
+// and a PoseGraph for loop closure.
 class MapBuilder {
  public:
   using LocalSlamResultCallback =
@@ -95,7 +95,7 @@ class MapBuilder {
 
   int num_trajectory_builders() const;
 
-  mapping::SparsePoseGraph* sparse_pose_graph();
+  mapping::PoseGraph* pose_graph();
 
  private:
   const proto::MapBuilderOptions options_;
@@ -103,7 +103,7 @@ class MapBuilder {
 
   std::unique_ptr<mapping_2d::SparsePoseGraph> sparse_pose_graph_2d_;
   std::unique_ptr<mapping_3d::SparsePoseGraph> sparse_pose_graph_3d_;
-  mapping::SparsePoseGraph* sparse_pose_graph_;
+  mapping::PoseGraph* pose_graph_;
 
   LocalSlamResultCallback local_slam_result_callback_;
 
diff --git a/cartographer/mapping/sparse_pose_graph.cc b/cartographer/mapping/pose_graph.cc
similarity index 86%
rename from cartographer/mapping/sparse_pose_graph.cc
rename to cartographer/mapping/pose_graph.cc
index 717df6e..1b08e5e 100644
--- a/cartographer/mapping/sparse_pose_graph.cc
+++ b/cartographer/mapping/pose_graph.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/mapping/sparse_pose_graph.h"
+#include "cartographer/mapping/pose_graph.h"
 
 #include "cartographer/mapping/pose_graph/constraint_builder.h"
 #include "cartographer/mapping/pose_graph/optimization_problem_options.h"
@@ -25,48 +25,45 @@ namespace cartographer {
 namespace mapping {
 
 proto::SparsePoseGraph::Constraint::Tag ToProto(
-    const SparsePoseGraph::Constraint::Tag& tag) {
+    const PoseGraph::Constraint::Tag& tag) {
   switch (tag) {
-    case SparsePoseGraph::Constraint::Tag::INTRA_SUBMAP:
+    case PoseGraph::Constraint::Tag::INTRA_SUBMAP:
       return proto::SparsePoseGraph::Constraint::INTRA_SUBMAP;
-    case SparsePoseGraph::Constraint::Tag::INTER_SUBMAP:
+    case PoseGraph::Constraint::Tag::INTER_SUBMAP:
       return proto::SparsePoseGraph::Constraint::INTER_SUBMAP;
   }
   LOG(FATAL) << "Unsupported tag.";
 }
 
-SparsePoseGraph::Constraint::Tag FromProto(
+PoseGraph::Constraint::Tag FromProto(
     const proto::SparsePoseGraph::Constraint::Tag& proto) {
   switch (proto) {
     case proto::SparsePoseGraph::Constraint::INTRA_SUBMAP:
-      return SparsePoseGraph::Constraint::Tag::INTRA_SUBMAP;
+      return PoseGraph::Constraint::Tag::INTRA_SUBMAP;
     case proto::SparsePoseGraph::Constraint::INTER_SUBMAP:
-      return SparsePoseGraph::Constraint::Tag::INTER_SUBMAP;
+      return PoseGraph::Constraint::Tag::INTER_SUBMAP;
     case ::google::protobuf::kint32max:
     case ::google::protobuf::kint32min:;
   }
   LOG(FATAL) << "Unsupported tag.";
 }
 
-std::vector<SparsePoseGraph::Constraint> FromProto(
+std::vector<PoseGraph::Constraint> FromProto(
     const ::google::protobuf::RepeatedPtrField<
-        ::cartographer::mapping::proto::SparsePoseGraph::Constraint>&
-        constraint_protos) {
-  std::vector<SparsePoseGraph::Constraint> constraints;
+        proto::SparsePoseGraph::Constraint>& constraint_protos) {
+  std::vector<PoseGraph::Constraint> constraints;
   for (const auto& constraint_proto : constraint_protos) {
     const mapping::SubmapId submap_id{
         constraint_proto.submap_id().trajectory_id(),
         constraint_proto.submap_id().submap_index()};
     const mapping::NodeId node_id{constraint_proto.node_id().trajectory_id(),
                                   constraint_proto.node_id().node_index()};
-    const SparsePoseGraph::Constraint::Pose pose{
+    const PoseGraph::Constraint::Pose pose{
         transform::ToRigid3(constraint_proto.relative_pose()),
         constraint_proto.translation_weight(),
         constraint_proto.rotation_weight()};
-    const SparsePoseGraph::Constraint::Tag tag =
-        FromProto(constraint_proto.tag());
-    constraints.push_back(
-        SparsePoseGraph::Constraint{submap_id, node_id, pose, tag});
+    const PoseGraph::Constraint::Tag tag = FromProto(constraint_proto.tag());
+    constraints.push_back(PoseGraph::Constraint{submap_id, node_id, pose, tag});
   }
   return constraints;
 }
@@ -99,7 +96,7 @@ proto::SparsePoseGraphOptions CreateSparsePoseGraphOptions(
   return options;
 }
 
-proto::SparsePoseGraph SparsePoseGraph::ToProto() {
+proto::SparsePoseGraph PoseGraph::ToProto() {
   proto::SparsePoseGraph proto;
 
   std::map<int, proto::Trajectory* const> trajectory_protos;
diff --git a/cartographer/mapping/sparse_pose_graph.h b/cartographer/mapping/pose_graph.h
similarity index 93%
rename from cartographer/mapping/sparse_pose_graph.h
rename to cartographer/mapping/pose_graph.h
index 8b47bc6..e8ba8d1 100644
--- a/cartographer/mapping/sparse_pose_graph.h
+++ b/cartographer/mapping/pose_graph.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_MAPPING_SPARSE_POSE_GRAPH_H_
-#define CARTOGRAPHER_MAPPING_SPARSE_POSE_GRAPH_H_
+#ifndef CARTOGRAPHER_MAPPING_POSE_GRAPH_H_
+#define CARTOGRAPHER_MAPPING_POSE_GRAPH_H_
 
 #include <memory>
 #include <set>
@@ -42,7 +42,7 @@ namespace mapping {
 proto::SparsePoseGraphOptions CreateSparsePoseGraphOptions(
     common::LuaParameterDictionary* const parameter_dictionary);
 
-class SparsePoseGraph {
+class PoseGraph {
  public:
   // A "constraint" as in the paper by Konolige, Kurt, et al. "Efficient sparse
   // pose adjustment for 2d mapping." Intelligent Robots and Systems (IROS),
@@ -77,11 +77,11 @@ class SparsePoseGraph {
     common::Time time;
   };
 
-  SparsePoseGraph() {}
-  virtual ~SparsePoseGraph() {}
+  PoseGraph() {}
+  virtual ~PoseGraph() {}
 
-  SparsePoseGraph(const SparsePoseGraph&) = delete;
-  SparsePoseGraph& operator=(const SparsePoseGraph&) = delete;
+  PoseGraph(const PoseGraph&) = delete;
+  PoseGraph& operator=(const PoseGraph&) = delete;
 
   // Inserts an IMU measurement.
   virtual void AddImuData(int trajectory_id,
@@ -163,7 +163,7 @@ class SparsePoseGraph {
                                         const common::Time time) = 0;
 };
 
-std::vector<SparsePoseGraph::Constraint> FromProto(
+std::vector<PoseGraph::Constraint> FromProto(
     const ::google::protobuf::RepeatedPtrField<
         ::cartographer::mapping::proto::SparsePoseGraph::Constraint>&
         constraint_protos);
@@ -171,4 +171,4 @@ std::vector<SparsePoseGraph::Constraint> FromProto(
 }  // namespace mapping
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_MAPPING_SPARSE_POSE_GRAPH_H_
+#endif  // CARTOGRAPHER_MAPPING_POSE_GRAPH_H_
diff --git a/cartographer/mapping_2d/pose_graph/constraint_builder.h b/cartographer/mapping_2d/pose_graph/constraint_builder.h
index 3060abc..ab9096f 100644
--- a/cartographer/mapping_2d/pose_graph/constraint_builder.h
+++ b/cartographer/mapping_2d/pose_graph/constraint_builder.h
@@ -30,8 +30,8 @@
 #include "cartographer/common/math.h"
 #include "cartographer/common/mutex.h"
 #include "cartographer/common/thread_pool.h"
+#include "cartographer/mapping/pose_graph.h"
 #include "cartographer/mapping/pose_graph/proto/constraint_builder_options.pb.h"
-#include "cartographer/mapping/sparse_pose_graph.h"
 #include "cartographer/mapping_2d/scan_matching/ceres_scan_matcher.h"
 #include "cartographer/mapping_2d/scan_matching/fast_correlative_scan_matcher.h"
 #include "cartographer/mapping_2d/submaps.h"
@@ -58,7 +58,7 @@ transform::Rigid2d ComputeSubmapPose(const Submap& submap);
 // This class is thread-safe.
 class ConstraintBuilder {
  public:
-  using Constraint = mapping::SparsePoseGraph::Constraint;
+  using Constraint = mapping::PoseGraph::Constraint;
   using Result = std::vector<Constraint>;
 
   ConstraintBuilder(
diff --git a/cartographer/mapping_2d/pose_graph/optimization_problem.h b/cartographer/mapping_2d/pose_graph/optimization_problem.h
index fd81636..d478a91 100644
--- a/cartographer/mapping_2d/pose_graph/optimization_problem.h
+++ b/cartographer/mapping_2d/pose_graph/optimization_problem.h
@@ -28,8 +28,8 @@
 #include "cartographer/common/port.h"
 #include "cartographer/common/time.h"
 #include "cartographer/mapping/id.h"
+#include "cartographer/mapping/pose_graph.h"
 #include "cartographer/mapping/pose_graph/proto/optimization_problem_options.pb.h"
-#include "cartographer/mapping/sparse_pose_graph.h"
 #include "cartographer/sensor/imu_data.h"
 #include "cartographer/sensor/map_by_time.h"
 #include "cartographer/sensor/odometry_data.h"
@@ -53,7 +53,7 @@ struct SubmapData {
 // Implements the SPA loop closure method.
 class OptimizationProblem {
  public:
-  using Constraint = mapping::SparsePoseGraph::Constraint;
+  using Constraint = mapping::PoseGraph::Constraint;
 
   explicit OptimizationProblem(
       const mapping::pose_graph::proto::OptimizationProblemOptions& options);
diff --git a/cartographer/mapping_2d/pose_graph/spa_cost_function.h b/cartographer/mapping_2d/pose_graph/spa_cost_function.h
index f770ace..b1c3b4a 100644
--- a/cartographer/mapping_2d/pose_graph/spa_cost_function.h
+++ b/cartographer/mapping_2d/pose_graph/spa_cost_function.h
@@ -22,7 +22,7 @@
 #include "Eigen/Core"
 #include "Eigen/Geometry"
 #include "cartographer/common/math.h"
-#include "cartographer/mapping/sparse_pose_graph.h"
+#include "cartographer/mapping/pose_graph.h"
 #include "cartographer/transform/rigid_transform.h"
 #include "cartographer/transform/transform.h"
 #include "ceres/ceres.h"
@@ -34,7 +34,7 @@ namespace pose_graph {
 
 class SpaCostFunction {
  public:
-  using Constraint = mapping::SparsePoseGraph::Constraint;
+  using Constraint = mapping::PoseGraph::Constraint;
 
   explicit SpaCostFunction(const Constraint::Pose& pose) : pose_(pose) {}
 
diff --git a/cartographer/mapping_2d/sparse_pose_graph.cc b/cartographer/mapping_2d/sparse_pose_graph.cc
index 370c4c9..e924c37 100644
--- a/cartographer/mapping_2d/sparse_pose_graph.cc
+++ b/cartographer/mapping_2d/sparse_pose_graph.cc
@@ -297,7 +297,7 @@ common::Time SparsePoseGraph::GetLatestNodeTime(
 
 void SparsePoseGraph::UpdateTrajectoryConnectivity(
     const Constraint& constraint) {
-  CHECK_EQ(constraint.tag, mapping::SparsePoseGraph::Constraint::INTER_SUBMAP);
+  CHECK_EQ(constraint.tag, mapping::PoseGraph::Constraint::INTER_SUBMAP);
   const common::Time time =
       GetLatestNodeTime(constraint.node_id, constraint.submap_id);
   trajectory_connectivity_state_.Connect(constraint.node_id.trajectory_id,
@@ -616,17 +616,16 @@ std::vector<std::vector<int>> SparsePoseGraph::GetConnectedTrajectories() {
   return trajectory_connectivity_state_.Components();
 }
 
-mapping::SparsePoseGraph::SubmapData SparsePoseGraph::GetSubmapData(
+mapping::PoseGraph::SubmapData SparsePoseGraph::GetSubmapData(
     const mapping::SubmapId& submap_id) {
   common::MutexLocker locker(&mutex_);
   return GetSubmapDataUnderLock(submap_id);
 }
 
-mapping::MapById<mapping::SubmapId, mapping::SparsePoseGraph::SubmapData>
+mapping::MapById<mapping::SubmapId, mapping::PoseGraph::SubmapData>
 SparsePoseGraph::GetAllSubmapData() {
   common::MutexLocker locker(&mutex_);
-  mapping::MapById<mapping::SubmapId, mapping::SparsePoseGraph::SubmapData>
-      submaps;
+  mapping::MapById<mapping::SubmapId, mapping::PoseGraph::SubmapData> submaps;
   for (const auto& submap_id_data : submap_data_) {
     submaps.Insert(submap_id_data.id,
                    GetSubmapDataUnderLock(submap_id_data.id));
@@ -659,7 +658,7 @@ transform::Rigid3d SparsePoseGraph::ComputeLocalToGlobalTransform(
              .inverse();
 }
 
-mapping::SparsePoseGraph::SubmapData SparsePoseGraph::GetSubmapDataUnderLock(
+mapping::PoseGraph::SubmapData SparsePoseGraph::GetSubmapDataUnderLock(
     const mapping::SubmapId& submap_id) {
   const auto it = submap_data_.find(submap_id);
   if (it == submap_data_.end()) {
@@ -737,8 +736,8 @@ void SparsePoseGraph::TrimmingHandle::MarkSubmapAsTrimmed(
   parent_->constraint_builder_.DeleteScanMatcher(submap_id);
   parent_->optimization_problem_.TrimSubmap(submap_id);
 
-  // Remove the 'nodes_to_remove' from the sparse pose graph and the
-  // optimization problem.
+  // Remove the 'nodes_to_remove' from the pose graph and the optimization
+  // problem.
   for (const mapping::NodeId& node_id : nodes_to_remove) {
     parent_->trajectory_nodes_.Trim(node_id);
     parent_->optimization_problem_.TrimTrajectoryNode(node_id);
diff --git a/cartographer/mapping_2d/sparse_pose_graph.h b/cartographer/mapping_2d/sparse_pose_graph.h
index 998847a..0769842 100644
--- a/cartographer/mapping_2d/sparse_pose_graph.h
+++ b/cartographer/mapping_2d/sparse_pose_graph.h
@@ -32,8 +32,8 @@
 #include "cartographer/common/mutex.h"
 #include "cartographer/common/thread_pool.h"
 #include "cartographer/common/time.h"
+#include "cartographer/mapping/pose_graph.h"
 #include "cartographer/mapping/pose_graph_trimmer.h"
-#include "cartographer/mapping/sparse_pose_graph.h"
 #include "cartographer/mapping/trajectory_connectivity_state.h"
 #include "cartographer/mapping_2d/pose_graph/constraint_builder.h"
 #include "cartographer/mapping_2d/pose_graph/optimization_problem.h"
@@ -56,7 +56,7 @@ namespace mapping_2d {
 // Each node has been matched against one or more submaps (adding a constraint
 // for each match), both poses of nodes and of submaps are to be optimized.
 // All constraints are between a submap i and a node j.
-class SparsePoseGraph : public mapping::SparsePoseGraph {
+class SparsePoseGraph : public mapping::PoseGraph {
  public:
   SparsePoseGraph(const mapping::proto::SparsePoseGraphOptions& options,
                   common::ThreadPool* thread_pool);
@@ -98,9 +98,9 @@ class SparsePoseGraph : public mapping::SparsePoseGraph {
   void AddTrimmer(std::unique_ptr<mapping::PoseGraphTrimmer> trimmer) override;
   void RunFinalOptimization() override;
   std::vector<std::vector<int>> GetConnectedTrajectories() override;
-  mapping::SparsePoseGraph::SubmapData GetSubmapData(
+  mapping::PoseGraph::SubmapData GetSubmapData(
       const mapping::SubmapId& submap_id) EXCLUDES(mutex_) override;
-  mapping::MapById<mapping::SubmapId, mapping::SparsePoseGraph::SubmapData>
+  mapping::MapById<mapping::SubmapId, mapping::PoseGraph::SubmapData>
   GetAllSubmapData() EXCLUDES(mutex_) override;
   transform::Rigid3d GetLocalToGlobalTransform(int trajectory_id)
       EXCLUDES(mutex_) override;
@@ -179,7 +179,7 @@ class SparsePoseGraph : public mapping::SparsePoseGraph {
           submap_transforms,
       int trajectory_id) const REQUIRES(mutex_);
 
-  mapping::SparsePoseGraph::SubmapData GetSubmapDataUnderLock(
+  mapping::PoseGraph::SubmapData GetSubmapDataUnderLock(
       const mapping::SubmapId& submap_id) REQUIRES(mutex_);
 
   common::Time GetLatestNodeTime(const mapping::NodeId& node_id,
diff --git a/cartographer/mapping_3d/pose_graph/constraint_builder.h b/cartographer/mapping_3d/pose_graph/constraint_builder.h
index 2285c02..e0d2e7d 100644
--- a/cartographer/mapping_3d/pose_graph/constraint_builder.h
+++ b/cartographer/mapping_3d/pose_graph/constraint_builder.h
@@ -54,7 +54,7 @@ namespace pose_graph {
 // This class is thread-safe.
 class ConstraintBuilder {
  public:
-  using Constraint = mapping::SparsePoseGraph::Constraint;
+  using Constraint = mapping::PoseGraph::Constraint;
   using Result = std::vector<Constraint>;
 
   ConstraintBuilder(
diff --git a/cartographer/mapping_3d/pose_graph/optimization_problem.cc b/cartographer/mapping_3d/pose_graph/optimization_problem.cc
index d0aa3ae..7fcf9c6 100644
--- a/cartographer/mapping_3d/pose_graph/optimization_problem.cc
+++ b/cartographer/mapping_3d/pose_graph/optimization_problem.cc
@@ -385,7 +385,7 @@ void OptimizationProblem::Solve(const std::vector<Constraint>& constraints,
         continue;
       }
 
-      const mapping::SparsePoseGraph::Constraint::Pose constraint_pose{
+      const mapping::PoseGraph::Constraint::Pose constraint_pose{
           *fixed_frame_pose, options_.fixed_frame_pose_translation_weight(),
           options_.fixed_frame_pose_rotation_weight()};
 
diff --git a/cartographer/mapping_3d/pose_graph/optimization_problem.h b/cartographer/mapping_3d/pose_graph/optimization_problem.h
index 531c6f3..8ab9e6b 100644
--- a/cartographer/mapping_3d/pose_graph/optimization_problem.h
+++ b/cartographer/mapping_3d/pose_graph/optimization_problem.h
@@ -28,8 +28,8 @@
 #include "cartographer/common/port.h"
 #include "cartographer/common/time.h"
 #include "cartographer/mapping/id.h"
+#include "cartographer/mapping/pose_graph.h"
 #include "cartographer/mapping/pose_graph/proto/optimization_problem_options.pb.h"
-#include "cartographer/mapping/sparse_pose_graph.h"
 #include "cartographer/sensor/fixed_frame_pose_data.h"
 #include "cartographer/sensor/imu_data.h"
 #include "cartographer/sensor/map_by_time.h"
@@ -53,7 +53,7 @@ struct SubmapData {
 // Implements the SPA loop closure method.
 class OptimizationProblem {
  public:
-  using Constraint = mapping::SparsePoseGraph::Constraint;
+  using Constraint = mapping::PoseGraph::Constraint;
 
   enum class FixZ { kYes, kNo };
 
diff --git a/cartographer/mapping_3d/pose_graph/spa_cost_function.h b/cartographer/mapping_3d/pose_graph/spa_cost_function.h
index 4e40dea..2638e95 100644
--- a/cartographer/mapping_3d/pose_graph/spa_cost_function.h
+++ b/cartographer/mapping_3d/pose_graph/spa_cost_function.h
@@ -22,7 +22,7 @@
 #include "Eigen/Core"
 #include "Eigen/Geometry"
 #include "cartographer/common/math.h"
-#include "cartographer/mapping/sparse_pose_graph.h"
+#include "cartographer/mapping/pose_graph.h"
 #include "cartographer/transform/rigid_transform.h"
 #include "cartographer/transform/transform.h"
 #include "ceres/ceres.h"
@@ -34,7 +34,7 @@ namespace pose_graph {
 
 class SpaCostFunction {
  public:
-  using Constraint = mapping::SparsePoseGraph::Constraint;
+  using Constraint = mapping::PoseGraph::Constraint;
 
   explicit SpaCostFunction(const Constraint::Pose& pose) : pose_(pose) {}
 
diff --git a/cartographer/mapping_3d/sparse_pose_graph.cc b/cartographer/mapping_3d/sparse_pose_graph.cc
index 3cdd598..0f12fa2 100644
--- a/cartographer/mapping_3d/sparse_pose_graph.cc
+++ b/cartographer/mapping_3d/sparse_pose_graph.cc
@@ -314,7 +314,7 @@ common::Time SparsePoseGraph::GetLatestNodeTime(
 
 void SparsePoseGraph::UpdateTrajectoryConnectivity(
     const Constraint& constraint) {
-  CHECK_EQ(constraint.tag, mapping::SparsePoseGraph::Constraint::INTER_SUBMAP);
+  CHECK_EQ(constraint.tag, mapping::PoseGraph::Constraint::INTER_SUBMAP);
   const common::Time time =
       GetLatestNodeTime(constraint.node_id, constraint.submap_id);
   trajectory_connectivity_state_.Connect(constraint.node_id.trajectory_id,
@@ -633,17 +633,16 @@ std::vector<std::vector<int>> SparsePoseGraph::GetConnectedTrajectories() {
   return trajectory_connectivity_state_.Components();
 }
 
-mapping::SparsePoseGraph::SubmapData SparsePoseGraph::GetSubmapData(
+mapping::PoseGraph::SubmapData SparsePoseGraph::GetSubmapData(
     const mapping::SubmapId& submap_id) {
   common::MutexLocker locker(&mutex_);
   return GetSubmapDataUnderLock(submap_id);
 }
 
-mapping::MapById<mapping::SubmapId, mapping::SparsePoseGraph::SubmapData>
+mapping::MapById<mapping::SubmapId, mapping::PoseGraph::SubmapData>
 SparsePoseGraph::GetAllSubmapData() {
   common::MutexLocker locker(&mutex_);
-  mapping::MapById<mapping::SubmapId, mapping::SparsePoseGraph::SubmapData>
-      submaps;
+  mapping::MapById<mapping::SubmapId, mapping::PoseGraph::SubmapData> submaps;
   for (const auto& submap_id_data : submap_data_) {
     submaps.Insert(submap_id_data.id,
                    GetSubmapDataUnderLock(submap_id_data.id));
@@ -675,7 +674,7 @@ transform::Rigid3d SparsePoseGraph::ComputeLocalToGlobalTransform(
              .inverse();
 }
 
-mapping::SparsePoseGraph::SubmapData SparsePoseGraph::GetSubmapDataUnderLock(
+mapping::PoseGraph::SubmapData SparsePoseGraph::GetSubmapDataUnderLock(
     const mapping::SubmapId& submap_id) {
   const auto it = submap_data_.find(submap_id);
   if (it == submap_data_.end()) {
@@ -751,8 +750,8 @@ void SparsePoseGraph::TrimmingHandle::MarkSubmapAsTrimmed(
   parent_->constraint_builder_.DeleteScanMatcher(submap_id);
   parent_->optimization_problem_.TrimSubmap(submap_id);
 
-  // Remove the 'nodes_to_remove' from the sparse pose graph and the
-  // optimization problem.
+  // Remove the 'nodes_to_remove' from the pose graph and the optimization
+  // problem.
   for (const mapping::NodeId& node_id : nodes_to_remove) {
     parent_->trajectory_nodes_.Trim(node_id);
     parent_->optimization_problem_.TrimTrajectoryNode(node_id);
diff --git a/cartographer/mapping_3d/sparse_pose_graph.h b/cartographer/mapping_3d/sparse_pose_graph.h
index 1ed97b0..482b1f4 100644
--- a/cartographer/mapping_3d/sparse_pose_graph.h
+++ b/cartographer/mapping_3d/sparse_pose_graph.h
@@ -32,8 +32,8 @@
 #include "cartographer/common/mutex.h"
 #include "cartographer/common/thread_pool.h"
 #include "cartographer/common/time.h"
+#include "cartographer/mapping/pose_graph.h"
 #include "cartographer/mapping/pose_graph_trimmer.h"
-#include "cartographer/mapping/sparse_pose_graph.h"
 #include "cartographer/mapping/trajectory_connectivity_state.h"
 #include "cartographer/mapping_3d/pose_graph/constraint_builder.h"
 #include "cartographer/mapping_3d/pose_graph/optimization_problem.h"
@@ -56,7 +56,7 @@ namespace mapping_3d {
 // Each node has been matched against one or more submaps (adding a constraint
 // for each match), both poses of nodes and of submaps are to be optimized.
 // All constraints are between a submap i and a node j.
-class SparsePoseGraph : public mapping::SparsePoseGraph {
+class SparsePoseGraph : public mapping::PoseGraph {
  public:
   SparsePoseGraph(const mapping::proto::SparsePoseGraphOptions& options,
                   common::ThreadPool* thread_pool);
@@ -98,9 +98,9 @@ class SparsePoseGraph : public mapping::SparsePoseGraph {
   void AddTrimmer(std::unique_ptr<mapping::PoseGraphTrimmer> trimmer) override;
   void RunFinalOptimization() override;
   std::vector<std::vector<int>> GetConnectedTrajectories() override;
-  mapping::SparsePoseGraph::SubmapData GetSubmapData(
+  mapping::PoseGraph::SubmapData GetSubmapData(
       const mapping::SubmapId& submap_id) EXCLUDES(mutex_) override;
-  mapping::MapById<mapping::SubmapId, mapping::SparsePoseGraph::SubmapData>
+  mapping::MapById<mapping::SubmapId, mapping::PoseGraph::SubmapData>
   GetAllSubmapData() EXCLUDES(mutex_) override;
   transform::Rigid3d GetLocalToGlobalTransform(int trajectory_id)
       EXCLUDES(mutex_) override;
@@ -179,7 +179,7 @@ class SparsePoseGraph : public mapping::SparsePoseGraph {
           submap_transforms,
       int trajectory_id) const REQUIRES(mutex_);
 
-  mapping::SparsePoseGraph::SubmapData GetSubmapDataUnderLock(
+  mapping::PoseGraph::SubmapData GetSubmapDataUnderLock(
       const mapping::SubmapId& submap_id) REQUIRES(mutex_);
 
   common::Time GetLatestNodeTime(const mapping::NodeId& node_id,