diff --git a/examples/SFMExampleExpressions_bal.cpp b/examples/SFMExampleExpressions_bal.cpp
index 4cc6b1185d..4fd6c1ada2 100644
--- a/examples/SFMExampleExpressions_bal.cpp
+++ b/examples/SFMExampleExpressions_bal.cpp
@@ -49,7 +49,7 @@ int main(int argc, char* argv[]) {
   SfmData mydata;
   readBAL(filename, mydata);
   cout << boost::format("read %1% tracks on %2% cameras\n") %
-              mydata.nrTracks() % mydata.nrCameras();
+              mydata.numberTracks() % mydata.numberCameras();
 
   // Create a factor graph
   ExpressionFactorGraph graph;
diff --git a/examples/SFMExample_bal.cpp b/examples/SFMExample_bal.cpp
index a93e438508..9d6e38a153 100644
--- a/examples/SFMExample_bal.cpp
+++ b/examples/SFMExample_bal.cpp
@@ -43,7 +43,7 @@ int main (int argc, char* argv[]) {
   // Load the SfM data from file
   SfmData mydata;
   readBAL(filename, mydata);
-  cout << boost::format("read %1% tracks on %2% cameras\n") % mydata.nrTracks() % mydata.nrCameras();
+  cout << boost::format("read %1% tracks on %2% cameras\n") % mydata.numberTracks() % mydata.numberCameras();
 
   // Create a factor graph
   NonlinearFactorGraph graph;
diff --git a/examples/SFMExample_bal_COLAMD_METIS.cpp b/examples/SFMExample_bal_COLAMD_METIS.cpp
index 90b397b06b..b59510c9fa 100644
--- a/examples/SFMExample_bal_COLAMD_METIS.cpp
+++ b/examples/SFMExample_bal_COLAMD_METIS.cpp
@@ -48,7 +48,7 @@ int main(int argc, char* argv[]) {
   SfmData mydata;
   readBAL(filename, mydata);
   cout << boost::format("read %1% tracks on %2% cameras\n") %
-              mydata.nrTracks() % mydata.nrCameras();
+              mydata.numberTracks() % mydata.numberCameras();
 
   // Create a factor graph
   NonlinearFactorGraph graph;
@@ -131,7 +131,7 @@ int main(int argc, char* argv[]) {
 
     cout << "Time comparison by solving " << filename << " results:" << endl;
     cout << boost::format("%1% point tracks and %2% cameras\n") %
-                mydata.nrTracks() % mydata.nrCameras()
+                mydata.numberTracks() % mydata.numberCameras()
          << endl;
 
     tictoc_print_();
diff --git a/gtsam/sfm/SfmData.cpp b/gtsam/sfm/SfmData.cpp
index 1e3d53601e..2f5396fcd1 100644
--- a/gtsam/sfm/SfmData.cpp
+++ b/gtsam/sfm/SfmData.cpp
@@ -32,26 +32,27 @@ using gtsam::symbol_shorthand::X;
 
 /* ************************************************************************** */
 void SfmData::print(const std::string &s) const {
-  std::cout << "Number of cameras = " << nrCameras() << std::endl;
-  std::cout << "Number of tracks = " << nrTracks() << std::endl;
+  std::cout << "Number of cameras = " << cameras.size() << std::endl;
+  std::cout << "Number of tracks = " << tracks.size() << std::endl;
 }
 
 /* ************************************************************************** */
 bool SfmData::equals(const SfmData &sfmData, double tol) const {
   // check number of cameras and tracks
-  if (nrCameras() != sfmData.nrCameras() || nrTracks() != sfmData.nrTracks()) {
+  if (cameras.size() != sfmData.cameras.size() ||
+      tracks.size() != sfmData.tracks.size()) {
     return false;
   }
 
   // check each camera
-  for (size_t i = 0; i < nrCameras(); ++i) {
+  for (size_t i = 0; i < cameras.size(); ++i) {
     if (!camera(i).equals(sfmData.camera(i), tol)) {
       return false;
     }
   }
 
   // check each track
-  for (size_t j = 0; j < nrTracks(); ++j) {
+  for (size_t j = 0; j < tracks.size(); ++j) {
     if (!track(j).equals(sfmData.track(j), tol)) {
       return false;
     }
@@ -264,19 +265,19 @@ bool writeBAL(const std::string &filename, SfmData &data) {
 
   // Write the number of camera poses and 3D points
   size_t nrObservations = 0;
-  for (size_t j = 0; j < data.nrTracks(); j++) {
-    nrObservations += data.tracks[j].nrMeasurements();
+  for (size_t j = 0; j < data.tracks.size(); j++) {
+    nrObservations += data.tracks[j].numberMeasurements();
   }
 
   // Write observations
-  os << data.nrCameras() << " " << data.nrTracks() << " " << nrObservations
-     << endl;
+  os << data.cameras.size() << " " << data.tracks.size() << " "
+     << nrObservations << endl;
   os << endl;
 
-  for (size_t j = 0; j < data.nrTracks(); j++) {  // for each 3D point j
+  for (size_t j = 0; j < data.tracks.size(); j++) {  // for each 3D point j
     const SfmTrack &track = data.tracks[j];
 
-    for (size_t k = 0; k < track.nrMeasurements();
+    for (size_t k = 0; k < track.numberMeasurements();
          k++) {  // for each observation of the 3D point j
       size_t i = track.measurements[k].first;  // camera id
       double u0 = data.cameras[i].calibration().px();
@@ -301,7 +302,7 @@ bool writeBAL(const std::string &filename, SfmData &data) {
   os << endl;
 
   // Write cameras
-  for (size_t i = 0; i < data.nrCameras(); i++) {  // for each camera
+  for (size_t i = 0; i < data.cameras.size(); i++) {  // for each camera
     Pose3 poseGTSAM = data.cameras[i].pose();
     Cal3Bundler cameraCalibration = data.cameras[i].calibration();
     Pose3 poseOpenGL = gtsam2openGL(poseGTSAM);
@@ -316,7 +317,7 @@ bool writeBAL(const std::string &filename, SfmData &data) {
   }
 
   // Write the points
-  for (size_t j = 0; j < data.nrTracks(); j++) {  // for each 3D point j
+  for (size_t j = 0; j < data.tracks.size(); j++) {  // for each 3D point j
     Point3 point = data.tracks[j].p;
     os << point.x() << endl;
     os << point.y() << endl;
@@ -336,8 +337,8 @@ bool writeBALfromValues(const std::string &filename, const SfmData &data,
 
   // Store poses or cameras in SfmData
   size_t nrPoses = values.count<Pose3>();
-  if (nrPoses == dataValues.nrCameras()) {  // we only estimated camera poses
-    for (size_t i = 0; i < dataValues.nrCameras(); i++) {  // for each camera
+  if (nrPoses == dataValues.cameras.size()) {  // we only estimated camera poses
+    for (size_t i = 0; i < dataValues.cameras.size(); i++) {  // for each camera
       Pose3 pose = values.at<Pose3>(X(i));
       Cal3Bundler K = dataValues.cameras[i].calibration();
       Camera camera(pose, K);
@@ -345,24 +346,24 @@ bool writeBALfromValues(const std::string &filename, const SfmData &data,
     }
   } else {
     size_t nrCameras = values.count<Camera>();
-    if (nrCameras == dataValues.nrCameras()) {  // we only estimated camera
-                                                // poses and calibration
-      for (size_t i = 0; i < nrCameras; i++) {  // for each camera
-        Key cameraKey = i;                      // symbol('c',i);
+    if (nrCameras == dataValues.cameras.size()) {  // we only estimated camera
+                                                   // poses and calibration
+      for (size_t i = 0; i < nrCameras; i++) {     // for each camera
+        Key cameraKey = i;                         // symbol('c',i);
         Camera camera = values.at<Camera>(cameraKey);
         dataValues.cameras[i] = camera;
       }
     } else {
       cout << "writeBALfromValues: different number of cameras in "
               "SfM_dataValues (#cameras "
-           << dataValues.nrCameras() << ") and values (#cameras " << nrPoses
+           << dataValues.cameras.size() << ") and values (#cameras " << nrPoses
            << ", #poses " << nrCameras << ")!!" << endl;
       return false;
     }
   }
 
   // Store 3D points in SfmData
-  size_t nrPoints = values.count<Point3>(), nrTracks = dataValues.nrTracks();
+  size_t nrPoints = values.count<Point3>(), nrTracks = dataValues.tracks.size();
   if (nrPoints != nrTracks) {
     cout << "writeBALfromValues: different number of points in "
             "SfM_dataValues (#points= "
diff --git a/gtsam/sfm/SfmData.h b/gtsam/sfm/SfmData.h
index 8770fcd4a2..e2a6985f20 100644
--- a/gtsam/sfm/SfmData.h
+++ b/gtsam/sfm/SfmData.h
@@ -50,10 +50,10 @@ struct SfmData {
   void addCamera(const SfmCamera& cam) { cameras.push_back(cam); }
 
   /// The number of reconstructed 3D points
-  size_t nrTracks() const { return tracks.size(); }
+  size_t numberTracks() const { return tracks.size(); }
 
   /// The number of cameras
-  size_t nrCameras() const { return cameras.size(); }
+  size_t numberCameras() const { return cameras.size(); }
 
   /// The track formed by series of landmark measurements
   SfmTrack track(size_t idx) const { return tracks[idx]; }
diff --git a/gtsam/sfm/SfmTrack.cpp b/gtsam/sfm/SfmTrack.cpp
index e97d5a405d..d571e7c359 100644
--- a/gtsam/sfm/SfmTrack.cpp
+++ b/gtsam/sfm/SfmTrack.cpp
@@ -39,13 +39,13 @@ bool SfmTrack::equals(const SfmTrack& sfmTrack, double tol) const {
   }
 
   // compare size of vectors for measurements and siftIndices
-  if (nrMeasurements() != sfmTrack.nrMeasurements() ||
+  if (numberMeasurements() != sfmTrack.numberMeasurements() ||
       siftIndices.size() != sfmTrack.siftIndices.size()) {
     return false;
   }
 
   // compare measurements (order sensitive)
-  for (size_t idx = 0; idx < nrMeasurements(); ++idx) {
+  for (size_t idx = 0; idx < numberMeasurements(); ++idx) {
     SfmMeasurement measurement = measurements[idx];
     SfmMeasurement otherMeasurement = sfmTrack.measurements[idx];
 
diff --git a/gtsam/sfm/SfmTrack.h b/gtsam/sfm/SfmTrack.h
index 35603a6f36..ee9128d04b 100644
--- a/gtsam/sfm/SfmTrack.h
+++ b/gtsam/sfm/SfmTrack.h
@@ -68,7 +68,7 @@ struct SfmTrack {
   }
 
   /// Total number of measurements in this track
-  size_t nrMeasurements() const { return measurements.size(); }
+  size_t numberMeasurements() const { return measurements.size(); }
 
   /// Get the measurement (camera index, Point2) at pose index `idx`
   const SfmMeasurement& measurement(size_t idx) const {
diff --git a/gtsam/sfm/ShonanAveraging.h b/gtsam/sfm/ShonanAveraging.h
index de12de4782..a5c31534c3 100644
--- a/gtsam/sfm/ShonanAveraging.h
+++ b/gtsam/sfm/ShonanAveraging.h
@@ -165,7 +165,7 @@ class GTSAM_EXPORT ShonanAveraging {
   size_t nrUnknowns() const { return nrUnknowns_; }
 
   /// Return number of measurements
-  size_t nrMeasurements() const { return measurements_.size(); }
+  size_t numberMeasurements() const { return measurements_.size(); }
 
   /// k^th binary measurement
   const BinaryMeasurement<Rot> &measurement(size_t k) const {
diff --git a/gtsam/sfm/sfm.i b/gtsam/sfm/sfm.i
index aaafa8e372..14f183d169 100644
--- a/gtsam/sfm/sfm.i
+++ b/gtsam/sfm/sfm.i
@@ -16,7 +16,7 @@ class SfmTrack {
 
   std::vector<pair<size_t, gtsam::Point2>> measurements;
 
-  size_t nrMeasurements() const;
+  size_t numberMeasurements() const;
   pair<size_t, gtsam::Point2> measurement(size_t idx) const;
   pair<size_t, size_t> siftIndex(size_t idx) const;
   void addMeasurement(size_t idx, const gtsam::Point2& m);
@@ -31,8 +31,8 @@ class SfmTrack {
 #include <gtsam/sfm/SfmData.h>
 class SfmData {
   SfmData();
-  size_t nrCameras() const;
-  size_t nrTracks() const;
+  size_t numberCameras() const;
+  size_t numberTracks() const;
   gtsam::PinholeCamera<gtsam::Cal3Bundler> camera(size_t idx) const;
   gtsam::SfmTrack track(size_t idx) const;
   void addTrack(const gtsam::SfmTrack& t);
@@ -136,7 +136,7 @@ class ShonanAveraging2 {
 
   // Query properties
   size_t nrUnknowns() const;
-  size_t nrMeasurements() const;
+  size_t numberMeasurements() const;
   gtsam::Rot2 measured(size_t i);
   gtsam::KeyVector keys(size_t i);
 
@@ -184,7 +184,7 @@ class ShonanAveraging3 {
 
   // Query properties
   size_t nrUnknowns() const;
-  size_t nrMeasurements() const;
+  size_t numberMeasurements() const;
   gtsam::Rot3 measured(size_t i);
   gtsam::KeyVector keys(size_t i);
 
diff --git a/gtsam/sfm/tests/testSfmData.cpp b/gtsam/sfm/tests/testSfmData.cpp
index f19542c260..bc1c8b645d 100644
--- a/gtsam/sfm/tests/testSfmData.cpp
+++ b/gtsam/sfm/tests/testSfmData.cpp
@@ -39,10 +39,10 @@ TEST(dataSet, Balbianello) {
   CHECK(readBundler(filename, mydata));
 
   // Check number of things
-  EXPECT_LONGS_EQUAL(5, mydata.nrCameras());
-  EXPECT_LONGS_EQUAL(544, mydata.nrTracks());
+  EXPECT_LONGS_EQUAL(5, mydata.numberCameras());
+  EXPECT_LONGS_EQUAL(544, mydata.numberTracks());
   const SfmTrack& track0 = mydata.tracks[0];
-  EXPECT_LONGS_EQUAL(3, track0.nrMeasurements());
+  EXPECT_LONGS_EQUAL(3, track0.numberMeasurements());
 
   // Check projection of a given point
   EXPECT_LONGS_EQUAL(0, track0.measurements[0].first);
@@ -60,10 +60,10 @@ TEST(dataSet, readBAL_Dubrovnik) {
   CHECK(readBAL(filename, mydata));
 
   // Check number of things
-  EXPECT_LONGS_EQUAL(3, mydata.nrCameras());
-  EXPECT_LONGS_EQUAL(7, mydata.nrTracks());
+  EXPECT_LONGS_EQUAL(3, mydata.numberCameras());
+  EXPECT_LONGS_EQUAL(7, mydata.numberTracks());
   const SfmTrack& track0 = mydata.tracks[0];
-  EXPECT_LONGS_EQUAL(3, track0.nrMeasurements());
+  EXPECT_LONGS_EQUAL(3, track0.numberMeasurements());
 
   // Check projection of a given point
   EXPECT_LONGS_EQUAL(0, track0.measurements[0].first);
@@ -119,16 +119,16 @@ TEST(dataSet, writeBAL_Dubrovnik) {
   CHECK(readBAL(filenameToWrite, writtenData));
 
   // Check that what we read is the same as what we wrote
-  EXPECT_LONGS_EQUAL(readData.nrCameras(), writtenData.nrCameras());
-  EXPECT_LONGS_EQUAL(readData.nrTracks(), writtenData.nrTracks());
+  EXPECT_LONGS_EQUAL(readData.numberCameras(), writtenData.numberCameras());
+  EXPECT_LONGS_EQUAL(readData.numberTracks(), writtenData.numberTracks());
 
-  for (size_t i = 0; i < readData.nrCameras(); i++) {
+  for (size_t i = 0; i < readData.numberCameras(); i++) {
     PinholeCamera<Cal3Bundler> expectedCamera = writtenData.cameras[i];
     PinholeCamera<Cal3Bundler> actualCamera = readData.cameras[i];
     EXPECT(assert_equal(expectedCamera, actualCamera));
   }
 
-  for (size_t j = 0; j < readData.nrTracks(); j++) {
+  for (size_t j = 0; j < readData.numberTracks(); j++) {
     // check point
     SfmTrack expectedTrack = writtenData.tracks[j];
     SfmTrack actualTrack = readData.tracks[j];
@@ -143,7 +143,7 @@ TEST(dataSet, writeBAL_Dubrovnik) {
     EXPECT(assert_equal(expectedRGB, actualRGB));
 
     // check measurements
-    for (size_t k = 0; k < actualTrack.nrMeasurements(); k++) {
+    for (size_t k = 0; k < actualTrack.numberMeasurements(); k++) {
       EXPECT_LONGS_EQUAL(expectedTrack.measurements[k].first,
                          actualTrack.measurements[k].first);
       EXPECT(assert_equal(expectedTrack.measurements[k].second,
@@ -163,11 +163,11 @@ TEST(dataSet, writeBALfromValues_Dubrovnik) {
       Pose3(Rot3::Ypr(-M_PI / 10, 0., -M_PI / 10), Point3(0.3, 0.1, 0.3));
 
   Values value;
-  for (size_t i = 0; i < readData.nrCameras(); i++) {  // for each camera
+  for (size_t i = 0; i < readData.numberCameras(); i++) {  // for each camera
     Pose3 pose = poseChange.compose(readData.cameras[i].pose());
     value.insert(X(i), pose);
   }
-  for (size_t j = 0; j < readData.nrTracks(); j++) {  // for each point
+  for (size_t j = 0; j < readData.numberTracks(); j++) {  // for each point
     Point3 point = poseChange.transformFrom(readData.tracks[j].p);
     value.insert(P(j), point);
   }
@@ -182,10 +182,10 @@ TEST(dataSet, writeBALfromValues_Dubrovnik) {
 
   // Check that the reprojection errors are the same and the poses are correct
   // Check number of things
-  EXPECT_LONGS_EQUAL(3, writtenData.nrCameras());
-  EXPECT_LONGS_EQUAL(7, writtenData.nrTracks());
+  EXPECT_LONGS_EQUAL(3, writtenData.numberCameras());
+  EXPECT_LONGS_EQUAL(7, writtenData.numberTracks());
   const SfmTrack& track0 = writtenData.tracks[0];
-  EXPECT_LONGS_EQUAL(3, track0.nrMeasurements());
+  EXPECT_LONGS_EQUAL(3, track0.numberMeasurements());
 
   // Check projection of a given point
   EXPECT_LONGS_EQUAL(0, track0.measurements[0].first);
diff --git a/gtsam/slam/SmartFactorBase.h b/gtsam/slam/SmartFactorBase.h
index 42a9508481..16712c429f 100644
--- a/gtsam/slam/SmartFactorBase.h
+++ b/gtsam/slam/SmartFactorBase.h
@@ -146,7 +146,7 @@ class GTSAM_EXPORT SmartFactorBase: public NonlinearFactor {
    */
   template<class SFM_TRACK>
   void add(const SFM_TRACK& trackToAdd) {
-    for (size_t k = 0; k < trackToAdd.nrMeasurements(); k++) {
+    for (size_t k = 0; k < trackToAdd.numberMeasurements(); k++) {
       this->measured_.push_back(trackToAdd.measurements[k].second);
       this->keys_.push_back(trackToAdd.measurements[k].first);
     }
diff --git a/gtsam/slam/tests/testEssentialMatrixFactor.cpp b/gtsam/slam/tests/testEssentialMatrixFactor.cpp
index 6df59ba489..1a5c64c8c2 100644
--- a/gtsam/slam/tests/testEssentialMatrixFactor.cpp
+++ b/gtsam/slam/tests/testEssentialMatrixFactor.cpp
@@ -632,14 +632,14 @@ TEST(EssentialMatrixFactor2, extraMinimization) {
   // We start with a factor graph and add constraints to it
   // Noise sigma is 1, assuming pixel measurements
   NonlinearFactorGraph graph;
-  for (size_t i = 0; i < data.nrTracks(); i++)
+  for (size_t i = 0; i < data.numberTracks(); i++)
     graph.emplace_shared<EssentialMatrixFactor2>(100, i, pA(i), pB(i), model2,
                                                  K);
 
   // Check error at ground truth
   Values truth;
   truth.insert(100, trueE);
-  for (size_t i = 0; i < data.nrTracks(); i++) {
+  for (size_t i = 0; i < data.numberTracks(); i++) {
     Point3 P1 = data.tracks[i].p;
     truth.insert(i, double(baseline / P1.z()));
   }
@@ -654,7 +654,7 @@ TEST(EssentialMatrixFactor2, extraMinimization) {
   // Check result
   EssentialMatrix actual = result.at<EssentialMatrix>(100);
   EXPECT(assert_equal(trueE, actual, 1e-1));
-  for (size_t i = 0; i < data.nrTracks(); i++)
+  for (size_t i = 0; i < data.numberTracks(); i++)
     EXPECT_DOUBLES_EQUAL(truth.at<double>(i), result.at<double>(i), 1e-1);
 
   // Check error at result
diff --git a/python/gtsam/examples/SFMExample_bal.py b/python/gtsam/examples/SFMExample_bal.py
index 1c4d76c837..8db1c2cb40 100644
--- a/python/gtsam/examples/SFMExample_bal.py
+++ b/python/gtsam/examples/SFMExample_bal.py
@@ -29,10 +29,10 @@
 def plot_scene(scene_data: gtsam.SfmData, result: gtsam.Values) -> None:
     """Plot the SFM results."""
     plot_vals = gtsam.Values()
-    for cam_idx in range(scene_data.nrCameras()):
+    for cam_idx in range(scene_data.numberCameras()):
         plot_vals.insert(C(cam_idx),
                          result.atPinholeCameraCal3Bundler(C(cam_idx)).pose())
-    for j in range(scene_data.nrTracks()):
+    for j in range(scene_data.numberTracks()):
         plot_vals.insert(P(j), result.atPoint3(P(j)))
 
     plot.plot_3d_points(0, plot_vals, linespec="g.")
@@ -47,8 +47,8 @@ def run(args: argparse.Namespace) -> None:
 
     # Load the SfM data from file
     scene_data = gtsam.readBal(input_file)
-    logging.info("read %d tracks on %d cameras\n", scene_data.nrTracks(),
-                 scene_data.nrCameras())
+    logging.info("read %d tracks on %d cameras\n", scene_data.numberTracks(),
+                 scene_data.numberCameras())
 
     # Create a factor graph
     graph = gtsam.NonlinearFactorGraph()
@@ -57,10 +57,10 @@ def run(args: argparse.Namespace) -> None:
     noise = gtsam.noiseModel.Isotropic.Sigma(2, 1.0)  # one pixel in u and v
 
     # Add measurements to the factor graph
-    for j in range(scene_data.nrTracks()):
+    for j in range(scene_data.numberTracks()):
         track = scene_data.track(j)  # SfmTrack
         # retrieve the SfmMeasurement objects
-        for m_idx in range(track.nrMeasurements()):
+        for m_idx in range(track.numberMeasurements()):
             # i represents the camera index, and uv is the 2d measurement
             i, uv = track.measurement(m_idx)
             # note use of shorthand symbols C and P
@@ -82,13 +82,13 @@ def run(args: argparse.Namespace) -> None:
 
     i = 0
     # add each PinholeCameraCal3Bundler
-    for cam_idx in range(scene_data.nrCameras()):
+    for cam_idx in range(scene_data.numberCameras()):
         camera = scene_data.camera(cam_idx)
         initial.insert(C(i), camera)
         i += 1
 
     # add each SfmTrack
-    for j in range(scene_data.nrTracks()):
+    for j in range(scene_data.numberTracks()):
         track = scene_data.track(j)
         initial.insert(P(j), track.point3())
 
diff --git a/python/gtsam/tests/test_SfmData.py b/python/gtsam/tests/test_SfmData.py
index 79004f03c9..4a45f91ba2 100644
--- a/python/gtsam/tests/test_SfmData.py
+++ b/python/gtsam/tests/test_SfmData.py
@@ -42,7 +42,7 @@ def test_tracks(self):
         self.tracks.addMeasurement(i1, uv_i1)
         self.tracks.addMeasurement(i2, uv_i2)
         # Number of measurements in the track is 2
-        self.assertEqual(self.tracks.nrMeasurements(), 2)
+        self.assertEqual(self.tracks.numberMeasurements(), 2)
         # camera_idx in the first measurement of the track corresponds to i1
         cam_idx, img_measurement = self.tracks.measurement(0)
         self.assertEqual(cam_idx, i1)
@@ -70,7 +70,7 @@ def test_data(self):
         self.data.addTrack(self.tracks)
         self.data.addTrack(track2)
         # Number of tracks in SfmData is 2
-        self.assertEqual(self.data.nrTracks(), 2)
+        self.assertEqual(self.data.numberTracks(), 2)
         # camera idx of first measurement of second track corresponds to i1
         cam_idx, img_measurement = self.data.track(1).measurement(0)
         self.assertEqual(cam_idx, i1)
diff --git a/tests/testGeneralSFMFactorB.cpp b/tests/testGeneralSFMFactorB.cpp
index 895c8484ba..0bf609adc5 100644
--- a/tests/testGeneralSFMFactorB.cpp
+++ b/tests/testGeneralSFMFactorB.cpp
@@ -49,7 +49,7 @@ TEST(PinholeCamera, BAL) {
   SharedNoiseModel unit2 = noiseModel::Unit::Create(2);
   NonlinearFactorGraph graph;
 
-  for (size_t j = 0; j < db.nrTracks(); j++) {
+  for (size_t j = 0; j < db.numberTracks(); j++) {
     for (const SfmMeasurement& m: db.tracks[j].measurements)
       graph.emplace_shared<sfmFactor>(m.second, unit2, m.first, P(j));
   }
diff --git a/timing/timeSFMBAL.cpp b/timing/timeSFMBAL.cpp
index 06b9637572..c1f36abd06 100644
--- a/timing/timeSFMBAL.cpp
+++ b/timing/timeSFMBAL.cpp
@@ -36,7 +36,7 @@ int main(int argc, char* argv[]) {
 
   // Build graph using conventional GeneralSFMFactor
   NonlinearFactorGraph graph;
-  for (size_t j = 0; j < db.nrTracks(); j++) {
+  for (size_t j = 0; j < db.numberTracks(); j++) {
     for (const SfmMeasurement& m: db.tracks[j].measurements) {
       size_t i = m.first;
       Point2 z = m.second;
diff --git a/timing/timeSFMBAL.h b/timing/timeSFMBAL.h
index 3108624ce5..347500cd2b 100644
--- a/timing/timeSFMBAL.h
+++ b/timing/timeSFMBAL.h
@@ -73,8 +73,8 @@ int optimize(const SfmData& db, const NonlinearFactorGraph& graph,
   if (gUseSchur) {
     // Create Schur-complement ordering
     Ordering ordering;
-    for (size_t j = 0; j < db.nrTracks(); j++) ordering.push_back(P(j));
-    for (size_t i = 0; i < db.nrCameras(); i++) {
+    for (size_t j = 0; j < db.numberTracks(); j++) ordering.push_back(P(j));
+    for (size_t i = 0; i < db.numberCameras(); i++) {
       ordering.push_back(C(i));
       if (separateCalibration) ordering.push_back(K(i));
     }
diff --git a/timing/timeSFMBALautodiff.cpp b/timing/timeSFMBALautodiff.cpp
index 63e1931459..083d367292 100644
--- a/timing/timeSFMBALautodiff.cpp
+++ b/timing/timeSFMBALautodiff.cpp
@@ -44,7 +44,7 @@ int main(int argc, char* argv[]) {
 
   // Build graph
   NonlinearFactorGraph graph;
-  for (size_t j = 0; j < db.nrTracks(); j++) {
+  for (size_t j = 0; j < db.numberTracks(); j++) {
     for (const SfmMeasurement& m: db.tracks[j].measurements) {
       size_t i = m.first;
       Point2 z = m.second;
diff --git a/timing/timeSFMBALcamTnav.cpp b/timing/timeSFMBALcamTnav.cpp
index cc26710403..a564a3a350 100644
--- a/timing/timeSFMBALcamTnav.cpp
+++ b/timing/timeSFMBALcamTnav.cpp
@@ -33,7 +33,7 @@ int main(int argc, char* argv[]) {
 
   // Build graph using conventional GeneralSFMFactor
   NonlinearFactorGraph graph;
-  for (size_t j = 0; j < db.nrTracks(); j++) {
+  for (size_t j = 0; j < db.numberTracks(); j++) {
     for (const SfmMeasurement& m: db.tracks[j].measurements) {
       size_t i = m.first;
       Point2 z = m.second;
diff --git a/timing/timeSFMBALnavTcam.cpp b/timing/timeSFMBALnavTcam.cpp
index 4c3bc06214..5299c85523 100644
--- a/timing/timeSFMBALnavTcam.cpp
+++ b/timing/timeSFMBALnavTcam.cpp
@@ -33,7 +33,7 @@ int main(int argc, char* argv[]) {
 
   // Build graph using conventional GeneralSFMFactor
   NonlinearFactorGraph graph;
-  for (size_t j = 0; j < db.nrTracks(); j++) {
+  for (size_t j = 0; j < db.numberTracks(); j++) {
     Point3_ nav_point_(P(j));
     for (const SfmMeasurement& m: db.tracks[j].measurements) {
       size_t i = m.first;
diff --git a/timing/timeSFMBALsmart.cpp b/timing/timeSFMBALsmart.cpp
index f37f35a394..fe2f7b925d 100644
--- a/timing/timeSFMBALsmart.cpp
+++ b/timing/timeSFMBALsmart.cpp
@@ -35,7 +35,7 @@ int main(int argc, char* argv[]) {
 
   // Add smart factors to graph
   NonlinearFactorGraph graph;
-  for (size_t j = 0; j < db.nrTracks(); j++) {
+  for (size_t j = 0; j < db.numberTracks(); j++) {
     auto smartFactor = boost::make_shared<SfmFactor>(gNoiseModel);
     for (const SfmMeasurement& m : db.tracks[j].measurements) {
       size_t i = m.first;