diff --git a/cartographer/mapping_2d/sparse_pose_graph/constraint_builder.cc b/cartographer/mapping_2d/pose_graph/constraint_builder.cc
similarity index 98%
rename from cartographer/mapping_2d/sparse_pose_graph/constraint_builder.cc
rename to cartographer/mapping_2d/pose_graph/constraint_builder.cc
index 30c0412..89d62af 100644
--- a/cartographer/mapping_2d/sparse_pose_graph/constraint_builder.cc
+++ b/cartographer/mapping_2d/pose_graph/constraint_builder.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/mapping_2d/sparse_pose_graph/constraint_builder.h"
+#include "cartographer/mapping_2d/pose_graph/constraint_builder.h"
 
 #include <cmath>
 #include <functional>
@@ -36,7 +36,7 @@
 
 namespace cartographer {
 namespace mapping_2d {
-namespace sparse_pose_graph {
+namespace pose_graph {
 
 transform::Rigid2d ComputeSubmapPose(const Submap& submap) {
   return transform::Project2D(submap.local_pose());
@@ -287,6 +287,6 @@ void ConstraintBuilder::DeleteScanMatcher(const mapping::SubmapId& submap_id) {
   submap_scan_matchers_.erase(submap_id);
 }
 
-}  // namespace sparse_pose_graph
+}  // namespace pose_graph
 }  // namespace mapping_2d
 }  // namespace cartographer
diff --git a/cartographer/mapping_2d/sparse_pose_graph/constraint_builder.h b/cartographer/mapping_2d/pose_graph/constraint_builder.h
similarity index 96%
rename from cartographer/mapping_2d/sparse_pose_graph/constraint_builder.h
rename to cartographer/mapping_2d/pose_graph/constraint_builder.h
index 44f61d8..3060abc 100644
--- a/cartographer/mapping_2d/sparse_pose_graph/constraint_builder.h
+++ b/cartographer/mapping_2d/pose_graph/constraint_builder.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_MAPPING_2D_SPARSE_POSE_GRAPH_CONSTRAINT_BUILDER_H_
-#define CARTOGRAPHER_MAPPING_2D_SPARSE_POSE_GRAPH_CONSTRAINT_BUILDER_H_
+#ifndef CARTOGRAPHER_MAPPING_2D_POSE_GRAPH_CONSTRAINT_BUILDER_H_
+#define CARTOGRAPHER_MAPPING_2D_POSE_GRAPH_CONSTRAINT_BUILDER_H_
 
 #include <array>
 #include <deque>
@@ -42,7 +42,7 @@
 
 namespace cartographer {
 namespace mapping_2d {
-namespace sparse_pose_graph {
+namespace pose_graph {
 
 // Returns (map <- submap) where 'submap' is a coordinate system at the origin
 // of the Submap.
@@ -178,8 +178,8 @@ class ConstraintBuilder {
   common::Histogram score_histogram_ GUARDED_BY(mutex_);
 };
 
-}  // namespace sparse_pose_graph
+}  // namespace pose_graph
 }  // namespace mapping_2d
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_MAPPING_2D_SPARSE_POSE_GRAPH_CONSTRAINT_BUILDER_H_
+#endif  // CARTOGRAPHER_MAPPING_2D_POSE_GRAPH_CONSTRAINT_BUILDER_H_
diff --git a/cartographer/mapping_2d/sparse_pose_graph/optimization_problem.cc b/cartographer/mapping_2d/pose_graph/optimization_problem.cc
similarity index 97%
rename from cartographer/mapping_2d/sparse_pose_graph/optimization_problem.cc
rename to cartographer/mapping_2d/pose_graph/optimization_problem.cc
index 4fa1b2e..c9ec296 100644
--- a/cartographer/mapping_2d/sparse_pose_graph/optimization_problem.cc
+++ b/cartographer/mapping_2d/pose_graph/optimization_problem.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/mapping_2d/sparse_pose_graph/optimization_problem.h"
+#include "cartographer/mapping_2d/pose_graph/optimization_problem.h"
 
 #include <algorithm>
 #include <array>
@@ -27,7 +27,7 @@
 #include "cartographer/common/ceres_solver_options.h"
 #include "cartographer/common/histogram.h"
 #include "cartographer/common/math.h"
-#include "cartographer/mapping_2d/sparse_pose_graph/spa_cost_function.h"
+#include "cartographer/mapping_2d/pose_graph/spa_cost_function.h"
 #include "cartographer/sensor/odometry_data.h"
 #include "cartographer/transform/transform.h"
 #include "ceres/ceres.h"
@@ -35,7 +35,7 @@
 
 namespace cartographer {
 namespace mapping_2d {
-namespace sparse_pose_graph {
+namespace pose_graph {
 
 namespace {
 
@@ -274,6 +274,6 @@ transform::Rigid3d OptimizationProblem::ComputeRelativePose(
                             second_node_data.initial_pose);
 }
 
-}  // namespace sparse_pose_graph
+}  // namespace pose_graph
 }  // namespace mapping_2d
 }  // namespace cartographer
diff --git a/cartographer/mapping_2d/sparse_pose_graph/optimization_problem.h b/cartographer/mapping_2d/pose_graph/optimization_problem.h
similarity index 93%
rename from cartographer/mapping_2d/sparse_pose_graph/optimization_problem.h
rename to cartographer/mapping_2d/pose_graph/optimization_problem.h
index 8b25631..fd81636 100644
--- a/cartographer/mapping_2d/sparse_pose_graph/optimization_problem.h
+++ b/cartographer/mapping_2d/pose_graph/optimization_problem.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_MAPPING_2D_SPARSE_POSE_GRAPH_OPTIMIZATION_PROBLEM_H_
-#define CARTOGRAPHER_MAPPING_2D_SPARSE_POSE_GRAPH_OPTIMIZATION_PROBLEM_H_
+#ifndef CARTOGRAPHER_MAPPING_2D_POSE_GRAPH_OPTIMIZATION_PROBLEM_H_
+#define CARTOGRAPHER_MAPPING_2D_POSE_GRAPH_OPTIMIZATION_PROBLEM_H_
 
 #include <array>
 #include <deque>
@@ -37,7 +37,7 @@
 
 namespace cartographer {
 namespace mapping_2d {
-namespace sparse_pose_graph {
+namespace pose_graph {
 
 struct NodeData {
   common::Time time;
@@ -106,8 +106,8 @@ class OptimizationProblem {
   sensor::MapByTime<sensor::OdometryData> odometry_data_;
 };
 
-}  // namespace sparse_pose_graph
+}  // namespace pose_graph
 }  // namespace mapping_2d
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_MAPPING_2D_SPARSE_POSE_GRAPH_OPTIMIZATION_PROBLEM_H_
+#endif  // CARTOGRAPHER_MAPPING_2D_POSE_GRAPH_OPTIMIZATION_PROBLEM_H_
diff --git a/cartographer/mapping_2d/sparse_pose_graph/spa_cost_function.h b/cartographer/mapping_2d/pose_graph/spa_cost_function.h
similarity index 91%
rename from cartographer/mapping_2d/sparse_pose_graph/spa_cost_function.h
rename to cartographer/mapping_2d/pose_graph/spa_cost_function.h
index ef113f7..f770ace 100644
--- a/cartographer/mapping_2d/sparse_pose_graph/spa_cost_function.h
+++ b/cartographer/mapping_2d/pose_graph/spa_cost_function.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_MAPPING_2D_SPARSE_POSE_GRAPH_SPA_COST_FUNCTION_H_
-#define CARTOGRAPHER_MAPPING_2D_SPARSE_POSE_GRAPH_SPA_COST_FUNCTION_H_
+#ifndef CARTOGRAPHER_MAPPING_2D_POSE_GRAPH_SPA_COST_FUNCTION_H_
+#define CARTOGRAPHER_MAPPING_2D_POSE_GRAPH_SPA_COST_FUNCTION_H_
 
 #include <array>
 
@@ -30,7 +30,7 @@
 
 namespace cartographer {
 namespace mapping_2d {
-namespace sparse_pose_graph {
+namespace pose_graph {
 
 class SpaCostFunction {
  public:
@@ -81,8 +81,8 @@ class SpaCostFunction {
   const Constraint::Pose pose_;
 };
 
-}  // namespace sparse_pose_graph
+}  // namespace pose_graph
 }  // namespace mapping_2d
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_MAPPING_2D_SPARSE_POSE_GRAPH_SPA_COST_FUNCTION_H_
+#endif  // CARTOGRAPHER_MAPPING_2D_POSE_GRAPH_SPA_COST_FUNCTION_H_
diff --git a/cartographer/mapping_2d/sparse_pose_graph.cc b/cartographer/mapping_2d/sparse_pose_graph.cc
index d0c6f80..370c4c9 100644
--- a/cartographer/mapping_2d/sparse_pose_graph.cc
+++ b/cartographer/mapping_2d/sparse_pose_graph.cc
@@ -87,9 +87,8 @@ std::vector<mapping::SubmapId> SparsePoseGraph::InitializeGlobalSubmapPoses(
     optimization_problem_.AddSubmap(
         trajectory_id,
         first_submap_pose *
-            sparse_pose_graph::ComputeSubmapPose(*insertion_submaps[0])
-                .inverse() *
-            sparse_pose_graph::ComputeSubmapPose(*insertion_submaps[1]));
+            pose_graph::ComputeSubmapPose(*insertion_submaps[0]).inverse() *
+            pose_graph::ComputeSubmapPose(*insertion_submaps[1]));
     return {last_submap_id,
             mapping::SubmapId{trajectory_id, last_submap_id.submap_index + 1}};
   }
@@ -232,8 +231,7 @@ void SparsePoseGraph::ComputeConstraintsForNode(
       transform::Rigid3d::Rotation(constant_data->gravity_alignment.inverse()));
   const transform::Rigid2d optimized_pose =
       optimization_problem_.submap_data().at(matching_id).global_pose *
-      sparse_pose_graph::ComputeSubmapPose(*insertion_submaps.front())
-          .inverse() *
+      pose_graph::ComputeSubmapPose(*insertion_submaps.front()).inverse() *
       pose;
   optimization_problem_.AddTrajectoryNode(
       matching_id.trajectory_id, constant_data->time, pose, optimized_pose,
@@ -245,8 +243,7 @@ void SparsePoseGraph::ComputeConstraintsForNode(
     CHECK(submap_data_.at(submap_id).state == SubmapState::kActive);
     submap_data_.at(submap_id).node_ids.emplace(node_id);
     const transform::Rigid2d constraint_transform =
-        sparse_pose_graph::ComputeSubmapPose(*insertion_submaps[i]).inverse() *
-        pose;
+        pose_graph::ComputeSubmapPose(*insertion_submaps[i]).inverse() * pose;
     constraints_.push_back(Constraint{submap_id,
                                       node_id,
                                       {transform::Embed3D(constraint_transform),
@@ -310,7 +307,7 @@ void SparsePoseGraph::UpdateTrajectoryConnectivity(
 
 void SparsePoseGraph::HandleWorkQueue() {
   constraint_builder_.WhenDone(
-      [this](const sparse_pose_graph::ConstraintBuilder::Result& result) {
+      [this](const pose_graph::ConstraintBuilder::Result& result) {
         {
           common::MutexLocker locker(&mutex_);
           constraints_.insert(constraints_.end(), result.begin(), result.end());
@@ -364,8 +361,8 @@ void SparsePoseGraph::WaitForAllComputations() {
   }
   std::cout << "\r\x1b[KOptimizing: Done.     " << std::endl;
   constraint_builder_.WhenDone(
-      [this, &notification](
-          const sparse_pose_graph::ConstraintBuilder::Result& result) {
+      [this,
+       &notification](const pose_graph::ConstraintBuilder::Result& result) {
         common::MutexLocker locker(&mutex_);
         constraints_.insert(constraints_.end(), result.begin(), result.end());
         notification = true;
@@ -407,7 +404,7 @@ void SparsePoseGraph::AddSubmapFromProto(
   submap_data_.at(submap_id).submap = submap_ptr;
   // Immediately show the submap at the 'global_submap_pose'.
   optimized_submap_transforms_.Insert(
-      submap_id, sparse_pose_graph::SubmapData{global_submap_pose_2d});
+      submap_id, pose_graph::SubmapData{global_submap_pose_2d});
   AddWorkItem([this, submap_id, global_submap_pose_2d]() REQUIRES(mutex_) {
     CHECK_EQ(frozen_trajectories_.count(submap_id.trajectory_id), 1);
     submap_data_.at(submap_id).state = SubmapState::kFinished;
@@ -638,7 +635,7 @@ SparsePoseGraph::GetAllSubmapData() {
 }
 
 transform::Rigid3d SparsePoseGraph::ComputeLocalToGlobalTransform(
-    const mapping::MapById<mapping::SubmapId, sparse_pose_graph::SubmapData>&
+    const mapping::MapById<mapping::SubmapId, pose_graph::SubmapData>&
         submap_transforms,
     const int trajectory_id) const {
   auto begin_it = submap_transforms.BeginOfTrajectory(trajectory_id);
diff --git a/cartographer/mapping_2d/sparse_pose_graph.h b/cartographer/mapping_2d/sparse_pose_graph.h
index 98f84c7..998847a 100644
--- a/cartographer/mapping_2d/sparse_pose_graph.h
+++ b/cartographer/mapping_2d/sparse_pose_graph.h
@@ -35,8 +35,8 @@
 #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/sparse_pose_graph/constraint_builder.h"
-#include "cartographer/mapping_2d/sparse_pose_graph/optimization_problem.h"
+#include "cartographer/mapping_2d/pose_graph/constraint_builder.h"
+#include "cartographer/mapping_2d/pose_graph/optimization_problem.h"
 #include "cartographer/mapping_2d/submaps.h"
 #include "cartographer/sensor/fixed_frame_pose_data.h"
 #include "cartographer/sensor/odometry_data.h"
@@ -175,7 +175,7 @@ class SparsePoseGraph : public mapping::SparsePoseGraph {
   // Computes the local to global map frame transform based on the given
   // optimized 'submap_transforms'.
   transform::Rigid3d ComputeLocalToGlobalTransform(
-      const mapping::MapById<mapping::SubmapId, sparse_pose_graph::SubmapData>&
+      const mapping::MapById<mapping::SubmapId, pose_graph::SubmapData>&
           submap_transforms,
       int trajectory_id) const REQUIRES(mutex_);
 
@@ -212,8 +212,8 @@ class SparsePoseGraph : public mapping::SparsePoseGraph {
   bool run_loop_closure_ GUARDED_BY(mutex_) = false;
 
   // Current optimization problem.
-  sparse_pose_graph::OptimizationProblem optimization_problem_;
-  sparse_pose_graph::ConstraintBuilder constraint_builder_ GUARDED_BY(mutex_);
+  pose_graph::OptimizationProblem optimization_problem_;
+  pose_graph::ConstraintBuilder constraint_builder_ GUARDED_BY(mutex_);
   std::vector<Constraint> constraints_ GUARDED_BY(mutex_);
 
   // Submaps get assigned an ID and state as soon as they are seen, even
@@ -227,7 +227,7 @@ class SparsePoseGraph : public mapping::SparsePoseGraph {
   int num_trajectory_nodes_ GUARDED_BY(mutex_) = 0;
 
   // Current submap transforms used for displaying data.
-  mapping::MapById<mapping::SubmapId, sparse_pose_graph::SubmapData>
+  mapping::MapById<mapping::SubmapId, pose_graph::SubmapData>
       optimized_submap_transforms_ GUARDED_BY(mutex_);
 
   // List of all trimmers to consult when optimizations finish.