Step 0: Install the dependencies: pcl and grid-map.
Step 1: Place your .pcd file in the <path-to-pcd-processor>/data directory.
Step 2: Run catkin build, then launch the process using ros launch pcd_processor pcd_processor.launch.
Files in the pcd_processor/memo directory are not used in this project; they simply serve as usage examples for utilizing a grid map converted from a local PCD file. The functions get_vehicle_rpy and get_vehicle_quaternion can project the vehicle's pose onto uneven terrain.