# Why geometry_msgs/Pose2D in ROS2 is not deprecated?

In ROS(1), geometry_msgs/Pose2D is deprecated.
In document of geometry_msgs/Pose2D, deprecated reasons are stated as follows.

Deprecated Please use the full 3D pose.

In general our recommendation is to use a full 3D representation of everything and for 2D specific applications make the appropriate projections into the plane for their calculations but optimally will preserve the 3D information during processing.

If we have parallel copies of 2D datatypes every UI and other pipeline will end up needing to have dual interfaces to plot everything. And you will end up with not being able to use 3D tools for 2D use cases even if they're completely valid, as you'd have to reimplement it with different inputs and outputs. It's not particularly hard to plot the 2D pose or compute the yaw error for the Pose message and there are already tools and libraries that can do this for you.

I think it is reasonable.
And I expected geometry_msgs/Pose2D will be abolished in ROS2.

But, it is not abolished in ROS2.
Moreover, expression "deprecated" was removed.
ref : ros2/common_interfaces

Please let me know why the expression "deprecated" has been removed in ROS2.

edit retag close merge delete

1

being a bit pedantic here but: The deprecation notice seem to have been added recently: https://github.com/ros/common_msgs/pu... More than 3 years after geometry_msgs was ported to ROS 2. Meaning the deprecation has not been "removed" in ROS 2, just not "added after the fact".

Though I agree with you, most likely the message should be removed completely in ROS 2 or at least the deprecation notice should be added like in ROS 1

( 2019-12-12 05:13:20 -0500 )edit
1

I disagree, there are many cases where I find a pose 2d to be incredibly helpful for debugging situations where the value of theta has some meaning to me. If you're working in a planar environment these can be useful waypoint markings. Especially if you think about trying to populate a web interface of positions and orientations, it doesn't make sense for a 2D representation of the world to have to do the trig to find the orientation relative to map frame for displaying debug instruments.

The last comment I would make is: who's it hurting by being around?

( 2019-12-12 12:38:01 -0500 )edit