Creating a 3D map with Velodyne data

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For anyone reading this at a later date (like me) there are a few other mapping options currently available:

SLAM

If you want to map your environment and you need a 3D map, you're often wanting to localize your laser scanner or robot at the same time - i.e. Simultaneous Localization and Mapping (SLAM) Below are some ROS-compatible options.

• Google Cartographer Google very recently released this 2D/3D SLAM package that will take laser and/or point cloud data and give you an occupancy map. You can find ROS integration here and Github code here. Not sure how they represent the map internally. Cartographer includes loop-closure.
• Berkley Localization and Mapping (BLAM) is another 3D LiDAR SLAM package. This doesn't have any papers on it that I am aware of, and it isn't being maintained (last commit was over two years ago). This uses the open-source and ROS-compatible Point Cloud Library for some of it's processing. Also does loop-closure
• Laser Odometry and Mapping (LOAM) is another 3D LiDAR SLAM package written by a PhD student. The source code is old and outdated because the student went on to commercialize their code with the company Kaarta. You can find a (somewhat) working version of the LOAM source code here. Does not perform any loop closure, so it's long-term use is quite limited.
• hector_slam/hector_mapping gives you LiDAR-based SLAM for systems with poor/no odometry (may suit you since you don't have wheel encoders). Also outputs an occupancy map. From memory I think this uses an elevation map (someone correct me If I'm wrong)
• rtabmap This is a Graph-based SLAM package that's evolved quite a bit over the years. It has a ROS-wrapper but can also operate as a stand-alone package. See the external website here for full details.

Of these options, I've played with Cartographer, BLAM and LOAM. Cartographer is quite hard to setup, tune and use. BLAM and LOAM are no longer maintained so I wouldn't recommend them now. Rtabmap seems to received a lot of attention and use recently so I'd start with that.

Mapping only

There are some packages that don't do SLAM and are only used for pure mapping (i.e. you'll have to use something else to localize the laser scanner or robot)

• Libpointmatcher While not strictly part of the ROS ecosystem, you can export clouds to a format LPM can then read. LPM is developed and maintained by a group working out of ETH Zurich. The developers have produced a decent number of papers on LPM, so you can get a good idea of what it is capable of by reading those (start with papers by François Pomerleau).
• Point Cloud Library PCL is not a mapping program. It is a collection of libraries for point cloud processing. But it includes many functions for positioning and registering (matching) LiDAR scans. PCL works well with ROS (it started life as a ROS library IIRC) and ...