diff --git a/src/ekf-mono-slam/include/feature/cartesian_map_feature.h b/src/ekf-mono-slam/include/feature/depth_map_feature.h
similarity index 85%
rename from src/ekf-mono-slam/include/feature/cartesian_map_feature.h
rename to src/ekf-mono-slam/include/feature/depth_map_feature.h
index 3628040..2301d04 100644
--- a/src/ekf-mono-slam/include/feature/cartesian_map_feature.h
+++ b/src/ekf-mono-slam/include/feature/depth_map_feature.h
@@ -5,9 +5,9 @@
 
 #include "map_feature.h"
 
-class CartesianMapFeature final : public MapFeature {
+class DepthMapFeature final : public MapFeature {
  public:
-  CartesianMapFeature(
+  DepthMapFeature(
     const Eigen::VectorXd& state,
     int position,
     const cv::Mat& descriptor_data,
diff --git a/src/ekf-mono-slam/include/filter/ekf.h b/src/ekf-mono-slam/include/filter/ekf.h
index 49f901d..e074d54 100644
--- a/src/ekf-mono-slam/include/filter/ekf.h
+++ b/src/ekf-mono-slam/include/filter/ekf.h
@@ -28,7 +28,7 @@ class EKF final {
   }
 
   [[nodiscard]] bool is_initilized() const {
-    return !state_->cartesian_features().empty() ||
+    return !state_->depth_features().empty() ||
            !state_->inverse_depth_features().empty();
   }
 
diff --git a/src/ekf-mono-slam/include/filter/state.h b/src/ekf-mono-slam/include/filter/state.h
index 8235d7c..71f0a9f 100644
--- a/src/ekf-mono-slam/include/filter/state.h
+++ b/src/ekf-mono-slam/include/filter/state.h
@@ -6,13 +6,13 @@
 #include <ostream>
 #include <vector>
 
-#include "feature/cartesian_map_feature.h"
+#include "feature/depth_map_feature.h"
 #include "feature/image_feature_measurement.h"
 #include "feature/inverse_depth_map_feature.h"
 #include "feature/map_feature.h"
 
 class MapFeature;
-class CartesianMapFeature;
+class DepthMapFeature;
 class InverseDepthMapFeature;
 class CovarianceMatrix;
 
@@ -61,15 +61,15 @@ class State final {
     return static_cast<int>(inverse_depth_features_.size());
   }
 
-  [[nodiscard]] int num_cartesian_features() const {
-    return static_cast<int>(cartesian_features_.size());
+  [[nodiscard]] int num_depth_features() const {
+    return static_cast<int>(depth_features_.size());
   }
 
   [[nodiscard]] int dimension() const { return dimension_; }
 
-  [[nodiscard]] const std::vector<std::shared_ptr<CartesianMapFeature>>&
-  cartesian_features() const {
-    return cartesian_features_;
+  [[nodiscard]] const std::vector<std::shared_ptr<DepthMapFeature>>&
+  depth_features() const {
+    return depth_features_;
   }
 
   [[nodiscard]] std::vector<std::shared_ptr<InverseDepthMapFeature>>
@@ -95,7 +95,7 @@ class State final {
 
   std::vector<std::shared_ptr<MapFeature>> features_;
   std::vector<std::shared_ptr<InverseDepthMapFeature>> inverse_depth_features_;
-  std::vector<std::shared_ptr<CartesianMapFeature>> cartesian_features_;
+  std::vector<std::shared_ptr<DepthMapFeature>> depth_features_;
 
   int dimension_;
 
diff --git a/src/ekf-mono-slam/src/feature/cartesian_map_feature.cpp b/src/ekf-mono-slam/src/feature/depth_map_feature.cpp
similarity index 76%
rename from src/ekf-mono-slam/src/feature/cartesian_map_feature.cpp
rename to src/ekf-mono-slam/src/feature/depth_map_feature.cpp
index 499fe36..5b46b9c 100644
--- a/src/ekf-mono-slam/src/feature/cartesian_map_feature.cpp
+++ b/src/ekf-mono-slam/src/feature/depth_map_feature.cpp
@@ -1,4 +1,4 @@
-#include "feature/cartesian_map_feature.h"
+#include "feature/depth_map_feature.h"
 
 #include <eigen3/Eigen/Core>
 #include <opencv2/core.hpp>
@@ -10,7 +10,7 @@
 using CameraParameters::fx;
 using CameraParameters::fy;
 
-CartesianMapFeature::CartesianMapFeature(
+DepthMapFeature::DepthMapFeature(
   const Eigen::VectorXd& state,
   int position,
   const cv::Mat& descriptor_data,
@@ -18,13 +18,13 @@ CartesianMapFeature::CartesianMapFeature(
 )
   : MapFeature(state, position, descriptor_data, index) {}
 
-Eigen::Vector3d CartesianMapFeature::directional_vector(
+Eigen::Vector3d DepthMapFeature::directional_vector(
   const Eigen::Matrix3d& rotation_matrix, const Eigen::Vector3d& camera_position
 ) {
   return rotation_matrix * (state_ - camera_position);
 }
 
 // TODO: implement method
-void CartesianMapFeature::measurement_jacobian(
+void DepthMapFeature::measurement_jacobian(
   const State& state, const CovarianceMatrix& covariance_matrix
 ) {}
diff --git a/src/ekf-mono-slam/src/feature/inverse_depth_map_feature.cpp b/src/ekf-mono-slam/src/feature/inverse_depth_map_feature.cpp
index 41b0e1c..cd12881 100644
--- a/src/ekf-mono-slam/src/feature/inverse_depth_map_feature.cpp
+++ b/src/ekf-mono-slam/src/feature/inverse_depth_map_feature.cpp
@@ -86,13 +86,12 @@ void InverseDepthMapFeature::measurement_jacobian(
   const auto dhi_dyi = dhd_dhu * dhu_dhc * dhc_dyi;  // Eq. (A.51)
 
   Eigen::Matrix2Xd dhi_dxm = Eigen::Matrix2Xd::Zero(
-    2,
-    6 * state.num_inverse_depth_features() + 3 * state.num_cartesian_features()
+    2, 6 * state.num_inverse_depth_features() + 3 * state.num_depth_features()
   );
 
   dhi_dxm.block(0, index_, 2, 6) = dhi_dyi;
 
-  // This matrix is 2x(13+6*num_inv_depth+3*num_cartesian)
+  // This matrix is 2x(13+6*num_inv_depth+3*num_depth)
   // If there's only 1 feature, it'd be 2x19
   Eigen::MatrixXd dhi_dx =
     Eigen::MatrixXd::Zero(2, dhi_dxc.cols() + dhi_dxm.cols());
diff --git a/src/ekf-mono-slam/src/filter/state.cpp b/src/ekf-mono-slam/src/filter/state.cpp
index 2c5409a..19a4579 100644
--- a/src/ekf-mono-slam/src/filter/state.cpp
+++ b/src/ekf-mono-slam/src/filter/state.cpp
@@ -114,12 +114,12 @@ void State::predict(const double delta_t) {
  * tracking.
  */
 void State::remove(const std::shared_ptr<MapFeature>& feature) {
-  if (const auto& cartesian_feature =
-        std::dynamic_pointer_cast<CartesianMapFeature>(feature)) {
+  if (const auto& depth_feature =
+        std::dynamic_pointer_cast<DepthMapFeature>(feature)) {
     std::erase_if(
-      cartesian_features_,
-      [&cartesian_feature](const std::shared_ptr<MapFeature>& f) {
-        return f == cartesian_feature;
+      depth_features_,
+      [&depth_feature](const std::shared_ptr<MapFeature>& f) {
+        return f == depth_feature;
       }
     );
   } else if (const auto& inverse_depth_feature =
@@ -195,10 +195,10 @@ void State::add(
  * @param feature The MapFeature object to be added.
  */
 void State::add(const std::shared_ptr<MapFeature>& feature) {
-  if (const auto& cartesian_feature =
-        std::dynamic_pointer_cast<CartesianMapFeature>(feature)) {
-    cartesian_features_.push_back(cartesian_feature);
-    features_.push_back(cartesian_feature);
+  if (const auto& depth_feature =
+        std::dynamic_pointer_cast<DepthMapFeature>(feature)) {
+    depth_features_.push_back(depth_feature);
+    features_.push_back(depth_feature);
   } else if (const auto& inverse_depth_feature =
                std::dynamic_pointer_cast<InverseDepthMapFeature>(feature)) {
     inverse_depth_features_.push_back(inverse_depth_feature);
diff --git a/src/ekf-mono-slam/test/itest_slam.cpp b/src/ekf-mono-slam/test/itest_slam.cpp
index ee037ca..672fb98 100644
--- a/src/ekf-mono-slam/test/itest_slam.cpp
+++ b/src/ekf-mono-slam/test/itest_slam.cpp
@@ -37,7 +37,7 @@ TEST(SLAMIntegration, FindFeatureInStateAndCovariance) {
 
   ASSERT_EQ(ekf.state()->dimension(), 13 + 20 * 6);
   ASSERT_EQ(ekf.state()->inverse_depth_features().size(), 20);
-  ASSERT_EQ(ekf.state()->cartesian_features().size(), 0);
+  ASSERT_EQ(ekf.state()->depth_features().size(), 0);
 
   for (size_t i = 0; i < image_features.size(); i++) {
     ASSERT_EQ(
diff --git a/src/ekf-mono-slam/test/utest_filter.cpp b/src/ekf-mono-slam/test/utest_filter.cpp
index a04b453..36d1b8b 100644
--- a/src/ekf-mono-slam/test/utest_filter.cpp
+++ b/src/ekf-mono-slam/test/utest_filter.cpp
@@ -45,20 +45,19 @@ TEST(ExtendedKalmanFilter, AddMapFeatureToState) {
     std::make_shared<InverseDepthMapFeature>(
       feature_state, 6, descriptor_data, 0
     );
-  const auto cartesian_map_feature = std::make_shared<CartesianMapFeature>(
-    feature_state, 13, descriptor_data, 1
-  );
+  const auto depth_map_feature =
+    std::make_shared<DepthMapFeature>(feature_state, 13, descriptor_data, 1);
 
   state.add(inverse_depth_map_feature);
-  state.add(cartesian_map_feature);
+  state.add(depth_map_feature);
 
   const std::vector<std::shared_ptr<InverseDepthMapFeature>>
     inverse_depth_features = state.inverse_depth_features();
-  const std::vector<std::shared_ptr<CartesianMapFeature>>
-    cartesian_map_features = state.cartesian_features();
+  const std::vector<std::shared_ptr<DepthMapFeature>> depth_map_features =
+    state.depth_features();
 
-  ASSERT_THAT(cartesian_map_features, SizeIs(1));
-  ASSERT_THAT(cartesian_map_features, Contains(cartesian_map_feature));
+  ASSERT_THAT(depth_map_features, SizeIs(1));
+  ASSERT_THAT(depth_map_features, Contains(depth_map_feature));
   ASSERT_THAT(inverse_depth_features, SizeIs(1));
   ASSERT_THAT(inverse_depth_features, Contains(inverse_depth_map_feature));
 }
@@ -74,23 +73,22 @@ TEST(ExtendedKalmanFilter, RemoveMapFeature) {
   const auto inverse_map_feature = std::make_shared<InverseDepthMapFeature>(
     feature_state, 13, descriptor_data, 0
   );
-  const auto cartesian_map_feature = std::make_shared<CartesianMapFeature>(
-    feature_state, 19, descriptor_data, 1
-  );
+  const auto depth_map_feature =
+    std::make_shared<DepthMapFeature>(feature_state, 19, descriptor_data, 1);
 
   state.add(inverse_map_feature);
-  state.add(cartesian_map_feature);
+  state.add(depth_map_feature);
 
   state.remove(inverse_map_feature);
-  state.remove(cartesian_map_feature);
+  state.remove(depth_map_feature);
 
   const std::vector<std::shared_ptr<InverseDepthMapFeature>>
     inverse_depth_features = state.inverse_depth_features();
-  const std::vector<std::shared_ptr<CartesianMapFeature>>
-    cartesian_map_features = state.cartesian_features();
+  const std::vector<std::shared_ptr<DepthMapFeature>> depth_map_features =
+    state.depth_features();
 
   ASSERT_THAT(inverse_depth_features, SizeIs(0));
-  ASSERT_THAT(cartesian_map_features, SizeIs(0));
+  ASSERT_THAT(depth_map_features, SizeIs(0));
 }
 
 TEST(ExtendedKalmanFilter, AddImageFeatureMeasurement) {
@@ -103,7 +101,7 @@ TEST(ExtendedKalmanFilter, AddImageFeatureMeasurement) {
   state.add(image_feature_measurement);
 
   ASSERT_THAT(state.inverse_depth_features().size(), Eq(1));
-  ASSERT_THAT(state.cartesian_features().size(), Eq(0));
+  ASSERT_THAT(state.depth_features().size(), Eq(0));
 }
 
 TEST(ExtendedKalmanFilter, InitCovariance) {