Start mapping with the ouster-cli

Installation

The Ouster CLI mapping functionality is a part of the Ouster SDK Python package.

To install the Ouster SDK with the mapping capabilities:

$ python3 install ouster-sdk

Mapping Tools

After installing the Ouster SDK and mapping dependencies, you can explore various mapping tools using a connected Ouster sensor or a PCAP/OSF file.

Use ouster-cli to view the available commands and options you can use --help. Try the following command:

ouster-cli source HOSTNAME / FILENAME --help

Currently, there are two main commands: slam and convert. You can further explore each command by accessing their respective submenus using the --help flag. For example:

ouster-cli source HOSTNAME / FILENAME slam --help

SLAM

Simultaneous localization and mapping (SLAM) is a technique that enables a system to construct a map of its surroundings while simultaneously determining its own position on that map. The Ouster SDK slam command writes lidar scans with per-column poses into an OSF file, an open-source custom file format for which Ouster provides conversion capabilities, allowing for the reconstruction of a detailed and precise map later.

Connect to a sensor or use a PCAP/OSF file Download Sample PCAP File

Note

Connecting to an Ouster sensor is covered in the Networking Guide section of the Ouster Sensor Documentation.

Then execute the following command:

ouster-cli source HOSTNAME / FILENAME slam viz -o sample.osf

Note

Please replace <HOSTNAME> with the corresponding hostname or IP of your sensor, and replace <PCAP_FILENAME> with the actual file path and name of the pcap file. Similarly, make the necessary substitutions in the subsequent commands.

The terminal will display details such as the output filename and the processing duration. The output filename must have the .osf extension in order to be used by the convert command.

You can modify settings like point size, color, switching 2D images, pause playing in the visualizer and display accumulated scans. More details can be found at the Ouster Visualizer and Scans Accumulator

Convert

The convert command converts the SLAM-generated OSF file to a point cloud data file format such as LAS (.las), PLY (.ply), or PCD (.pcd). The output file format depends on the extension of the output filename. Let’s use the OSF file generated from the SLAM command and convert it to a PLY file:

ouster-cli source sample.osf convert output.ply

The convert command automatically splits and downsamples the trajectory-adjusted point cloud into several files to prevent exporting a huge size file. The terminal will display details, and you will see the following printout for each output file:

Output file: output1.ply
3932160 points accumulated during this period,
154228 near points are removed [3.92 %],
1475955 down sampling points are removed [37.54 %],
2213506 zero range points are removed [56.29 %],
88471 points are saved [2.25 %].

You can adjust the minimal range, select different fields as values, and change the voxel size by referring to the --help flag for more information.

You can use an open source software CloudCompare to import and view the generated point cloud data files.

ouster-cli source sample.osf convert output.las