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Formats
Executables that load trajectories support different formats. You can specify the format you want to use with the mode switch (2nd argument), for example: evo_traj tum ... or evo_traj kitti .... This document provides information about these file formats.
Tip: if you don't know which format you should use for your SLAM algorithm, use the TUM format. It's simple, but can be converted to any other format later and doesn't require ROS.
Note: requires a ROS installation
Currently, bagfiles with topics that contain geometry_msgs/PoseStamped and nav_msgs/Odometry messages are supported.
More infos:
- http://wiki.ros.org/Bags
- http://docs.ros.org/api/geometry_msgs/html/msg/PoseStamped.html
- http://docs.ros.org/api/nav_msgs/html/msg/Odometry.html
Every sequence of the EuRoC MAV dataset has .csv files with various ground truth information. For us, only the first columns with the ground truth's trajectory are important (timestamps, positions and orientations).
You can find these files in the sequence folder: <sequence>/mav0/state_groundtruth_estimate0/data.csv
This format only makes sense for these ground truth files because they have additional data (which we don't need). If you use the EuRoC dataset, you usually need to save the trajectory in another format like the TUM format (e.g. ORB-SLAM does it like that).
In euroc mode, evo's metrics require you to give the reference in the EuRoC format and the estimated trajectory in the TUM format.
More infos: http://projects.asl.ethz.ch/datasets/doku.php?id=kmavvisualinertialdatasets#the_euroc_mav_dataset
This is actually not a real trajectory format because it has no timestamps - it only contains the poses in a text file. This means that you have to be careful when you want to compare two files in this format with a metric because the number of poses must be exactly the same.
Every row of the file contains the first 3 rows of a 4x4 homogeneous pose matrix (SE(3) matrix) flattened into one line, with each value separated by a space. For example, this pose matrix:
a b c d
e f g h
i j k l
0 0 0 1
will appear in the file as the row:
a b c d e f g h i j k l
More infos: http://www.cvlibs.net/datasets/kitti/eval_odometry.php
Every row has 8 entries containing timestamp (in seconds), position and orientation (as quaternion) with each value separated by a space:
timestamp x y z q_x q_y q_z q_w
More infos: https://vision.in.tum.de/data/datasets/rgbd-dataset/file_formats
In general, you can export trajectories to other formats with evo_traj using the --save_as_<other_format> options.
The following combinations are possible:
--save_as_bag |
--save_as_kitti |
--save_as_tum |
|
|---|---|---|---|
bag |
yes | yes | yes |
euroc |
yes | yes | yes |
kitti |
no (no timestamps) | yes | no (no timestamps) |
tum |
yes | yes | yes |
Example:
# export a EuRoC groundtruth file to a TUM trajectory
evo_traj euroc data.csv --save_as_tum
# (will be saved as data.tum)
# export TUM trajectories to KITTI format
evo_traj tum traj_1.txt traj_2.txt traj_3.txt --save_as_kitti
# (will be saved as *.kitti)
# export TUM trajectories to ROS bagfile
evo_traj tum traj_1.txt traj_2.txt traj_3.txt --save_as_bag
# (will be saved as <timestamp>.bag with topics traj_1, traj_2 and traj_3)
# and so on...There is no --save_as_euroc option because the EuRoC format only makes sense for the ground truth of the EuRoC dataset.
Note: Prior to version 1.0.5, there was a bug with the quaternions if TUM files were exported. Make sure your version is at least v1.0.5 with evo pkg --version or upgrade.
These files generated by a metric with the --save_results option contain the data that is needed to compare different results with evo_res. They are just .zip files that contain a few .json files and .npz files for storing larger numpy arrays.
If you want, you can also store a backup of the trajectories that were used to generate the result in the .zip file. To do this automatically whenever you use --save_results, change the settings:
evo_config set save_traj_in_zip true
Note that this will increase the size of the files.