Header

stamp is seconds since the Unix epoch (or since sim start); frame_id names the frame.

Full docstring

WHY float seconds, not ROS's (sec, nanosec): it is what every trajectory and controller in
this codebase already uses. float64 resolves 0.24 µs at today's epoch; `stamp_ns` and
`from_ns` exist for the lossless edge (bags, MCAP).

`meta` is context ROS has no field for (an origin, units, where the numbers came from, what
a cleaner changed) as an immutable ``str -> str`` mapping.
WHY on the header, not a free-form field on each message: the header is already the one place
a message says what its numbers are relative to (`frame_id`); meta extends that slot, so every
stamped message and every trajectory gets it once, and everything that keeps the header
(slicing, `.at()`, `resample`, serialisation) keeps it too. WHY strings only: the values are
read by people and other tools; a number would be `str()`-ed silently, so it is refused and
the caller picks the spelling (``repr(origin)``). Dropped on ROS export: std_msgs/Header has
only stamp and frame_id (docs/DESIGN.md, "Header.meta").

Import

from robot_msgs.std import Header

ROS 2std_msgs/msg/Header

Fields

Name	Type	Default
`stamp`	`float`	`0.0`
`frame_id`	`str`	`''`
`meta`	`Mapping[str, str]`	`FrozenDict()`

Example

One instance from the package's own test catalog; the output is its real repr().

Header(stamp=1761600000.25, frame_id='camera_color_optical_frame')

to_dict() as JSON

{
  "_type": "std/Header",
  "stamp": 1761600000.25,
  "frame_id": "camera_color_optical_frame",
  "meta": {}
}

Long arrays are cut after 16 values and say so with “…”.

Functions

Constructors

Classmethods and staticmethods: ways to build one.

`from_ns`

from_ns(stamp_ns: int, frame_id: str = '') -> Header

No docstring.

`from_sec_nanosec`

from_sec_nanosec(sec: int, nanosec: int, frame_id: str = '') -> Header

No docstring.

`now`

now(frame_id: str = '') -> Header

No docstring.

`from_dict`

from Msg

from_dict(data: Mapping[str, Any]) -> M

No docstring.

Properties

Read-only views computed from the fields.

`stamp_ns`

stamp_ns: int

No docstring.

Methods

Return new values; messages are never mutated.

`time_shifted`

time_shifted(seconds: float) -> Header

No docstring.

`to_sec_nanosec`

to_sec_nanosec() -> tuple[int, int]

ROS builtin_interfaces/Time split.

`replace`

from Msg

replace(**changes: Any) -> M

A copy with some fields changed. Validation runs again.

`to_dict`

from Msg

to_dict() -> dict[str, Any]

JSON-safe dict with a "_type" key; arrays keep their dtype and shape.

Used by

Types whose fields refer to it.

PoseStamped TransformStamped CameraInfo Image Imu JointState PointCloud JointTrajectory JointTrajectoryPoint PoseTrajectory PoseTrajectoryPoint Trajectory TrajectoryPoint Detection2D Detection2DArray Detection3D Detection3DArray