####仅作为笔记
环境：
ROS (tested with indigo, kinetic, and melodic)
gtsam (Georgia Tech Smoothing and Mapping library, 4.0.0-alpha2)
PCL
OpenCV

1. GTSAM

wget -O ~/Downloads/gtsam.zip https://github.com/borglab/gtsam/archive/4.0.0-alpha2.zip
cd ~/Downloads/ && unzip gtsam.zip -d ~/Downloads/
cd ~/Downloads/gtsam-4.0.0-alpha2/
mkdir build && cd build
cmake ..
sudo make install

2. PCL 1.8

#依赖
sudo apt-get update
sudo apt-get install git build-essential linux-libc-dev
sudo apt-get install cmake cmake-gui 
sudo apt-get install libusb-1.0-0-dev libusb-dev libudev-dev
sudo apt-get install mpi-default-dev openmpi-bin openmpi-common  
sudo apt-get install libflann1.8 libflann-dev
sudo apt-get install libeigen3-dev
sudo apt-get install libboost-all-dev
sudo apt-get install libvtk5.10-qt4 libvtk5.10 libvtk5-dev
sudo apt-get install libqhull* libgtest-dev
sudo apt-get install freeglut3-dev pkg-config
sudo apt-get install libxmu-dev libxi-dev 
sudo apt-get install mono-complete
sudo apt-get install qt-sdk openjdk-8-jdk openjdk-8-jre

#安装
git clone https://github.com/PointCloudLibrary/pcl.git 
cd pcl
mkdir build && cd build
cmake -DCMAKE_BUILD_TYPE=None -DCMAKE_INSTALL_PREFIX=/usr \ -DBUILD_GPU=ON -DBUILD_apps=ON -DBUILD_examples=ON \ -DCMAKE_INSTALL_PREFIX=/usr .. 
make -j4 && sudo make install

3. OpenCV
   参考：
   https://zhuanlan.zhihu.com/p/162883970

4. 安装lego-loam

cd ~/catkin_ws/src
git clone https://github.com/RobustFieldAutonomyLab/LeGO-LOAM.git
cd ..
catkin_make -j1

5. 测试

##数据集：https://github.com/RobustFieldAutonomyLab/jackal_dataset_20170608
roslaunch lego_loam run.launch
rosbag play *.bag --clock --topic /velodyne_points /imu/data

如果使用的是其他线数的激光雷达，修改以下内容：

extern const int N_SCAN = 16;
extern const int Horizon_SCAN = 1800;
extern const float ang_res_x = 0.2;
extern const float ang_res_y = 2.0;
extern const float ang_bottom = 15.0;
extern const int groundScanInd = 7;

6. 测试结果