Add a ROS topic stream
This page assumes knowledge of ROS.
Configure your catkin workspace for custom messages
Before configuring a custom ROS message, you'll have to provide the Formant agent with the path to your catkin workspace. For more information, see Environment variables for the Formant Agent.
This guide will teach you how to ingest ROS topic data directly into Formant.
Step 1: Create the ROS topic stream
- In Formant, in the upper-left corner, open the menu and click Settings.
- Click Devices, and then click on the device you want to configure.
- Click the Telemetry tab, and then click Add Stream.
- Click ROS Topic. This will open the New ROS Topic Stream configuration window:
| Property | Usage |
|---|---|
| Telemetry stream name | Give the stream a name. |
| On demand | If ON, this stream will store data locally on your device, and only upload data to Formant when you click Retrieve on-demand data. Rate limit controls the rate at which datapoints are added to the on-device buffer. For more information, see On demand streams.If OFF, this stream will ingest periodically. Rate limit controls the rate of data ingestion. |
| Video encoding | Only applicable for sensor_msgs/Image and sensor_msgs/CompressedImage streams. Choose whether you want images ingested on this stream to be encoded as a video. |
| Validation schema | Only applicable for JSON and text streams. Choose a configuration schema for this stream. |
| Ingestion topic | Enter the ROS topic name, starting with /. The text field will auto-populate with ROS topics detected on your device. |
| ROS message path (optional) | Give the path into the ROS message to the data you want, in field.arr[x][y] format. This can be as complex as necessary, e.g., field.arr[x][y].subfield.arr2[i]. |
Add tags (e.g. key: value) (optional) | Add tags to each datapoint of this stream. For more information on tags, see Configure access levels. |
| Rate limit (Hz) (optional) | If On demand is ON: Set the rate at which data is added to the on-device buffer. Data in the on-device buffer will be ingested by the agent when you click Retrieve on-demand data. For more information, see On demand streams.If On demand is OFF: Set the rate at which data is ingested.The default rate is 0.5 Hz. |
Supported formats for streaming video using
sensor_msgs/ImagemessagesFor a
sensor_msgs/Imagetopic to be a valid input to Formant's automatic video encoding, it must have a value for theencodingfield that matches one of the following exactly:
rgb8rgba8bgr8bgra8mono8mono168UC1yuv422If your
encodingvalue is unsupported, you may be able to adjust theencodingfield of thesensor_msgs/Imagemessage without changing the underlying data. In some cases, you will need to transform both the data and theencodingproperty to supported values.If you have trouble with this, please contact our Customer Success team via the Intercom messenger in the bottom-right corner of this page, or via email at [email protected].
- When you're finished configuring your stream, click Done, and then Save. Finally, Save your device settings.
Step 2: Add stream to a view
Once you've added a stream to your device, your next step is to add it to a view in Formant.
Add the streams you want to visualize, and then move on to Viewing data in Formant.
Adding multiple ROS topics to the same module
You can add multiple ROS topics of the same data type to the same module.
In the New ROS Topic Stream window seen above, you can click the Add ROS Topic button multiple times to add multiple streams.
When adding multiple topics to the same stream, you must provide a unique set of tags for each topic.
Adding multiple ROS topics to the same stream.
ROS topic type vs. Formant data type
The table below shows a mapping from ROS topic type to Formant datapoint type:
| ROS message type | Formant datapoint type |
|---|---|
std_msgs/Stringstd_msgs/Char | Text |
std_msgs/UInt8std_msgs/UInt16std_msgs/UInt32std_msgs/UInt64std_msgs/Int8std_msgs/Int16std_msgs/Int32std_msgs/Int64std_msgs/Float32std_msgs/Float64 | Numeric |
std_msgs/Bool | Bitset |
sensor_msgs/NavSatFix | Location |
sensor_msgs/BatteryState | Battery |
sensor_msgs/Imagesensor_msgs/CompressedImage(with Video encoding set to OFF) | Image |
sensor_msgs/Imagesensor_msgs/CompressedImage(with Video encoding set to ON) | Video |
sensor_msgs/PointCloud2sensor_msgs/LaserScan | Point cloud |
| All other ROS types (including custom messages) | JSON |
If you notice an issue with this page or need help, please reach out to us! Use the 'Did this page help you?' buttons below, or get in contact with our Customer Success team via the Intercom messenger in the bottom-right corner of this page, or at [email protected].
Updated 24 days ago