diff --git a/oh_my_loam/mapper/map.cc b/oh_my_loam/mapper/map.cc
new file mode 100644
index 0000000..1af8e64
--- /dev/null
+++ b/oh_my_loam/mapper/map.cc
@@ -0,0 +1,200 @@
+#include "oh_my_loam/mapper/map.h"
+
+#include "common/log/log.h"
+
+namespace oh_my_loam {
+
+Row::Row(int n) {
+  row_.resize(n);
+  for (auto &cloud : row_) cloud.reset(new TPointCloud);
+}
+
+TPointCloudPtr &Row::at(int ix) {
+  return row_.at(ix);
+}
+
+const TPointCloudPtr &Row::at(int ix) const {
+  return row_.at(ix);
+}
+
+void Row::Clear() {
+  for (auto &cloud : row_) cloud->clear();
+}
+
+TPointCloudPtr Row::GetAllPoints() const {
+  TPointCloudPtr cloud_all(new TPointCloud);
+  for (const auto &cloud : row_) *cloud_all += *cloud;
+  return cloud_all;
+}
+
+Grid::Grid(int m, int n) {
+  for (int i = 0; i < m; ++i) grid_.emplace_back(n);
+}
+
+void Grid::Clear() {
+  for (auto &row : grid_) row.Clear();
+}
+
+Row &Grid::at(int ix) {
+  return grid_.at(ix);
+}
+
+const Row &Grid::at(int ix) const {
+  return grid_.at(ix);
+}
+
+TPointCloudPtr Grid::GetAllPoints() const {
+  TPointCloudPtr cloud_all(new TPointCloud);
+  for (const auto &row : grid_) *cloud_all += *row.GetAllPoints();
+  return cloud_all;
+}
+
+Map::Map(int z_size, int y_size, int x_size, double z_step, double y_step,
+         double x_step)
+    : z_size_(z_size),
+      y_size_(y_size),
+      x_size_(x_size),
+      z_step_(z_step),
+      y_step_(y_step),
+      x_step_(x_step),
+      z_center_(x_size / 2),
+      y_center_(y_size / 2),
+      x_center_(x_size / 2) {
+  ACHECK(z_size % 2 == 1 && y_size % 2 == 1 && x_size % 2 == 1);
+  ACHECK(z_step_ > 0.0 && y_step_ > 0.0 && x_step_ > 0.0);
+  for (int i = 0; i < z_size; ++i) map_.emplace_back(y_size, x_size);
+}
+
+Grid &Map::at(int z_ix) {
+  return map_.at(z_ix);
+}
+
+const Grid &Map::at(int z_ix) const {
+  return map_.at(z_ix);
+}
+
+Row &Map::at(int z_ix, int y_ix) {
+  return map_.at(z_ix).at(y_ix);
+}
+
+const Row &Map::at(int z_ix, int y_ix) const {
+  return map_.at(z_ix).at(y_ix);
+}
+
+TPointCloudPtr &Map::at(int z_ix, int y_ix, int x_ix) {
+  return map_.at(z_ix).at(y_ix).at(x_ix);
+}
+
+const TPointCloudPtr &Map::at(int z_ix, int y_ix, int x_ix) const {
+  return map_.at(z_ix).at(y_ix).at(x_ix);
+}
+
+TPointCloudPtr &Map::at(const Index &index) {
+  return map_.at(index.k).at(index.j).at(index.i);
+}
+
+const TPointCloudPtr &Map::at(const Index &index) const {
+  return map_.at(index.k).at(index.j).at(index.i);
+}
+
+void Map::Clear() {
+  for (auto &grid : map_) grid.Clear();
+}
+
+void Map::ShiftZ(int n) {
+  if (n == 0) return;
+  if (n > 0) {
+    for (int k = z_size_ - 1; k >= n; --k) {
+      std::swap(this->at(k), this->at(k - n));
+    }
+    for (int k = 0; k < n; ++k) this->at(k).Clear();
+  } else {
+    for (int k = 0; k < z_size_ - n; ++k) {
+      std::swap(this->at(k), this->at(k + n));
+    }
+    for (int k = z_size_ - n - 1; k < z_size_; ++k) {
+      this->at(k).Clear();
+    }
+  }
+  z_center_ -= n;
+}
+
+void Map::ShiftY(int n) {
+  if (n == 0) return;
+  for (int k = 0; k < z_size_; ++k) {
+    if (n > 0) {
+      for (int j = y_size_ - 1; j >= n; --j) {
+        std::swap(this->at(k, j), this->at(k, j - n));
+      }
+      for (int j = 0; j < n; ++j) this->at(k, j).Clear();
+    } else {
+      for (int j = 0; j < y_size_ - n; ++j) {
+        std::swap(this->at(k, j), this->at(k, j + n));
+      }
+      for (int j = y_size_ - n - 1; j < y_size_; ++j) {
+        this->at(k, j).Clear();
+      }
+    }
+  }
+  y_center_ -= n;
+}
+
+void Map::ShiftX(int n) {
+  if (n == 0) return;
+  for (int k = 0; k < z_size_; ++k) {
+    for (int j = 0; j < y_size_; ++j) {
+      if (n > 0) {
+        for (int i = x_size_ - 1; i >= n; --i) {
+          std::swap(this->at(k, j, i), this->at(k, j, i - n));
+        }
+        for (int i = 0; i < n; ++i) this->at(k, j, i)->clear();
+
+      } else {
+        for (int i = 0; i < x_size_ - n; ++i) {
+          std::swap(this->at(k, j, i), this->at(k, j, i + n));
+        }
+        for (int i = x_size_ - n - 1; i < x_size_; ++i) {
+          this->at(k, j, i)->clear();
+        }
+      }
+    }
+  }
+  x_center_ -= n;
+}
+
+Index Map::GetIndex(const TPoint &point) {
+  Index index;
+  index.k = static_cast<int>(point.x / z_step_) + z_center_;
+  index.j = static_cast<int>(point.x / y_step_) + y_center_;
+  index.i = static_cast<int>(point.x / x_step_) + x_center_;
+  return index;
+}
+
+std::vector<Index> Map::GetSurrIndices(const TPoint &point, int n) {
+  std::vector<Index> indices;
+  Index index = GetIndex(point);
+  for (int k = -n; k <= n; ++k) {
+    for (int j = -n; j <= n; ++j) {
+      for (int i = -n; i <= n; ++i) {
+        indices.emplace_back(index.k + k, index.j + j, index.i + i);
+      }
+    }
+  }
+  return indices;
+}
+
+TPointCloudPtr Map::GetSurrPoints(const TPoint &point, int n) {
+  TPointCloudPtr cloud_all(new TPointCloud);
+  for (const auto &index : GetSurrIndices(point, n)) {
+    *cloud_all += *this->at(index);
+  }
+  return cloud_all;
+}
+
+TPointCloudPtr Map::GetAllPoints() const {
+  TPointCloudPtr cloud_all(new TPointCloud);
+  for (const auto &grid : map_) *cloud_all += *grid.GetAllPoints();
+  return cloud_all;
+}
+
+}  // namespace oh_my_loam
\ No newline at end of file
diff --git a/oh_my_loam/mapper/map.h b/oh_my_loam/mapper/map.h
new file mode 100644
index 0000000..d9df42d
--- /dev/null
+++ b/oh_my_loam/mapper/map.h
@@ -0,0 +1,99 @@
+#pragma once
+
+#include <vector>
+
+#include "common/macro/macros.h"
+#include "oh_my_loam/base/types.h"
+
+namespace oh_my_loam {
+
+class Row;
+
+class Grid;
+
+struct Index {
+  int k, j, i;
+};
+
+class Map {
+ public:
+  Map(int z_size, int y_size, int x_size, double z_step, double y_step,
+      double x_step);
+
+  Grid &at(int z_ix);
+
+  const Grid &at(int z_ix) const;
+
+  Row &at(int z_ix, int y_ix);
+
+  const Row &at(int z_ix, int y_ix) const;
+
+  TPointCloudPtr &at(int z_ix, int y_ix, int x_ix);
+
+  const TPointCloudPtr &at(int z_ix, int y_ix, int x_ix) const;
+
+  TPointCloudPtr &at(const Index &index);
+
+  const TPointCloudPtr &at(const Index &index) const;
+
+  void Clear();
+
+  void ShiftZ(int n);
+
+  void ShiftY(int n);
+
+  void ShiftX(int n);
+
+  Index GetIndex(const TPoint &point);
+
+  std::vector<Index> GetSurrIndices(const TPoint &point, int n);
+
+  TPointCloudPtr GetSurrPoints(const TPoint &point, int n);
+
+  TPointCloudPtr GetAllPoints() const;
+
+ private:
+  int z_size_, y_size_, x_size_;
+
+  double z_step_, y_step_, x_step_;
+
+  int z_center_, y_center_, x_center_;
+
+  std::vector<Grid> map_;
+
+  DISALLOW_COPY_AND_ASSIGN(Map);
+};
+
+class Row {
+ public:
+  explicit Row(int n);
+
+  TPointCloudPtr &at(int ix);
+
+  const TPointCloudPtr &at(int ix) const;
+
+  void Clear();
+
+  TPointCloudPtr GetAllPoints() const;
+
+ private:
+  std::vector<TPointCloudPtr> row_;
+};
+
+class Grid {
+ public:
+  Grid(int m, int n);
+
+  void Clear();
+
+  Row &at(int ix);
+
+  const Row &at(int ix) const;
+
+  TPointCloudPtr GetAllPoints() const;
+
+ private:
+  std::vector<Row> grid_;
+};
+
+}  // namespace oh_my_loam
\ No newline at end of file
diff --git a/oh_my_loam/mapper/mapper.cc b/oh_my_loam/mapper/mapper.cc
index 6effbe1..26ebc72 100644
--- a/oh_my_loam/mapper/mapper.cc
+++ b/oh_my_loam/mapper/mapper.cc
@@ -30,7 +30,6 @@ void Mapper::Process(double timestamp, const TPointCloudConstPtr &cloud_corn,
     return;
   }
   if (GetState() == DONE) {
-    Update();
   } else {  // RUNNING
   }
 }