# TrajectoryStates.msg

## Overview

`TrajectoryStates.msg` reports the state of each trajectory known to Cartographer. It maps trajectory IDs to their current state via parallel arrays.

## Constants

| Constant | Value | Meaning |
| --- | --- | --- |
| `ACTIVE` | `0` | The trajectory is actively being mapped. |
| `FINISHED` | `1` | The trajectory has finished mapping. |
| `FROZEN` | `2` | The trajectory is frozen and no longer being optimized. |
| `DELETED` | `3` | The trajectory has been deleted. |

## Fields

| Field | Type | Description |
| --- | --- | --- |
| `header` | `std_msgs/Header` | The standard ROS header. |
| `trajectory_id` | `int32[]` | The list of trajectory IDs. |
| `trajectory_state` | `uint8[]` | The state of each trajectory, parallel to `trajectory_id` and using the constants above. |

## Usage

- The arrays are parallel: `trajectory_state[i]` corresponds to `trajectory_id[i]`.
- This message is returned by `GetTrajectoryStates.srv`.
- Consumers can use the state to decide whether a trajectory is ready for finalization or can be reused.