tf2_geometry

The tf2_geometry package is an add-on for the geometry2 library, used in ROS 2 to represent 3D coordinate transformations. It can simplify 3D inputs into 2D objects. By providing types such as Point2D, Line2D, and LineSegment2D, it enables various classical graphical operations that are especially useful for wheel-driven vehicles operating in 2D environments.

Transform2D

The Transform2D is a class which can be used to describe poses and transformations in 2D space. It can be generated from a classical tf2::Transform object using the functions:

• tf2::Transform2D &tf2::to_2D(const Transform &src, tf2::Transform2D &des) or
• tf2::Transform2D tf2::to_Transform2D(const Transform &src)

There are also functions available to create directly Point2D objects:

• tf2::Point2D &tf2::to_2D(const Transform &src, tf2::Point2D &des) or
• tf2::Point2D tf2::to_Point2D(const Transform &src)

Point2D, Line2D and LineSegment2D

Geometric objects are created easily with:

• tf2::Point2D(const tf2Scalar &x, const tf2Scalar &y) and
• tf2::Line2D(const tf2::Point2D &p0, const tf2::Point2D &p1) and
• tf2::LineSegment2D(const tf2::Point2D &p0, const tf2::Point2D &p1)

Point2D and Line2D provide:

• distance of point to line
• closest point on line
• normal
• ...

Point2D and LineSegment2D also provide the same functions but take the line endpoints into account.