# Class Pose2d

java.lang.Object
edu.wpi.first.math.geometry.Pose2d
All Implemented Interfaces:
`Interpolatable<Pose2d>`

```public class Pose2d
extends Object
implements Interpolatable<Pose2d>```
Represents a 2D pose containing translational and rotational elements.
• ## Constructor Summary

Constructors
Constructor Description
`Pose2d()`
Constructs a pose at the origin facing toward the positive X axis.
```Pose2d​(double x, double y, Rotation2d rotation)```
Constructs a pose with x and y translations instead of a separate Translation2d.
```Pose2d​(Translation2d translation, Rotation2d rotation)```
Constructs a pose with the specified translation and rotation.
• ## Method Summary

Modifier and Type Method Description
`Pose2d` `div​(double scalar)`
Divides the current pose by a scalar.
`boolean` `equals​(Object obj)`
Checks equality between this Pose2d and another object.
`Pose2d` `exp​(Twist2d twist)`
Obtain a new Pose2d from a (constant curvature) velocity.
`Rotation2d` `getRotation()`
Returns the rotational component of the transformation.
`Translation2d` `getTranslation()`
Returns the translation component of the transformation.
`double` `getX()`
Returns the X component of the pose's translation.
`double` `getY()`
Returns the Y component of the pose's translation.
`int` `hashCode()`
`Pose2d` ```interpolate​(Pose2d endValue, double t)```
Return the interpolated value.
`Twist2d` `log​(Pose2d end)`
Returns a Twist2d that maps this pose to the end pose.
`Transform2d` `minus​(Pose2d other)`
Returns the Transform2d that maps the one pose to another.
`Pose2d` `nearest​(List<Pose2d> poses)`
Returns the nearest Pose2d from a list of poses.
`Pose2d` `plus​(Transform2d other)`
Transforms the pose by the given transformation and returns the new transformed pose.
`Pose2d` `relativeTo​(Pose2d other)`
Returns the current pose relative to the given pose.
`Pose2d` `times​(double scalar)`
Multiplies the current pose by a scalar.
`String` `toString()`
`Pose2d` `transformBy​(Transform2d other)`
Transforms the pose by the given transformation and returns the new pose.

### Methods inherited from class java.lang.Object

`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`
• ## Constructor Details

• ### Pose2d

public Pose2d()
Constructs a pose at the origin facing toward the positive X axis.
• ### Pose2d

public Pose2d​(Translation2d translation, Rotation2d rotation)
Constructs a pose with the specified translation and rotation.
Parameters:
`translation` - The translational component of the pose.
`rotation` - The rotational component of the pose.
• ### Pose2d

public Pose2d​(double x, double y, Rotation2d rotation)
Constructs a pose with x and y translations instead of a separate Translation2d.
Parameters:
`x` - The x component of the translational component of the pose.
`y` - The y component of the translational component of the pose.
`rotation` - The rotational component of the pose.
• ## Method Details

• ### plus

public Pose2d plus​(Transform2d other)
Transforms the pose by the given transformation and returns the new transformed pose.
``` [x_new]    [cos, -sin, 0][transform.x]
[y_new] += [sin,  cos, 0][transform.y]
[t_new]    [  0,    0, 1][transform.t]
```
Parameters:
`other` - The transform to transform the pose by.
Returns:
The transformed pose.
• ### minus

public Transform2d minus​(Pose2d other)
Returns the Transform2d that maps the one pose to another.
Parameters:
`other` - The initial pose of the transformation.
Returns:
The transform that maps the other pose to the current pose.
• ### getTranslation

Returns the translation component of the transformation.
Returns:
The translational component of the pose.
• ### getX

public double getX()
Returns the X component of the pose's translation.
Returns:
The x component of the pose's translation.
• ### getY

public double getY()
Returns the Y component of the pose's translation.
Returns:
The y component of the pose's translation.
• ### getRotation

Returns the rotational component of the transformation.
Returns:
The rotational component of the pose.
• ### times

public Pose2d times​(double scalar)
Multiplies the current pose by a scalar.
Parameters:
`scalar` - The scalar.
Returns:
The new scaled Pose2d.
• ### div

public Pose2d div​(double scalar)
Divides the current pose by a scalar.
Parameters:
`scalar` - The scalar.
Returns:
The new scaled Pose2d.
• ### transformBy

public Pose2d transformBy​(Transform2d other)
Transforms the pose by the given transformation and returns the new pose. See + operator for the matrix multiplication performed.
Parameters:
`other` - The transform to transform the pose by.
Returns:
The transformed pose.
• ### relativeTo

public Pose2d relativeTo​(Pose2d other)
Returns the current pose relative to the given pose.

This function can often be used for trajectory tracking or pose stabilization algorithms to get the error between the reference and the current pose.

Parameters:
`other` - The pose that is the origin of the new coordinate frame that the current pose will be converted into.
Returns:
The current pose relative to the new origin pose.
• ### exp

public Pose2d exp​(Twist2d twist)
Obtain a new Pose2d from a (constant curvature) velocity.

See Controls Engineering in the FIRST Robotics Competition section 10.2 "Pose exponential" for a derivation.

The twist is a change in pose in the robot's coordinate frame since the previous pose update. When the user runs exp() on the previous known field-relative pose with the argument being the twist, the user will receive the new field-relative pose.

"Exp" represents the pose exponential, which is solving a differential equation moving the pose forward in time.

Parameters:
`twist` - The change in pose in the robot's coordinate frame since the previous pose update. For example, if a non-holonomic robot moves forward 0.01 meters and changes angle by 0.5 degrees since the previous pose update, the twist would be Twist2d(0.01, 0.0, Units.degreesToRadians(0.5)).
Returns:
The new pose of the robot.
• ### log

public Twist2d log​(Pose2d end)
Returns a Twist2d that maps this pose to the end pose. If c is the output of `a.Log(b)`, then `a.Exp(c)` would yield b.
Parameters:
`end` - The end pose for the transformation.
Returns:
The twist that maps this to end.
• ### nearest

public Pose2d nearest​(List<Pose2d> poses)
Returns the nearest Pose2d from a list of poses. If two or more poses in the list have the same distance from this pose, return the one with the closest rotation component.
Parameters:
`poses` - The list of poses to find the nearest.
Returns:
The nearest Pose2d from the list.
• ### toString

public String toString()
Overrides:
`toString` in class `Object`
• ### equals

public boolean equals​(Object obj)
Checks equality between this Pose2d and another object.
Overrides:
`equals` in class `Object`
Parameters:
`obj` - The other object.
Returns:
Whether the two objects are equal or not.
• ### hashCode

public int hashCode()
Overrides:
`hashCode` in class `Object`
• ### interpolate

public Pose2d interpolate​(Pose2d endValue, double t)
Description copied from interface: `Interpolatable`
Return the interpolated value. This object is assumed to be the starting position, or lower bound.
Specified by:
`interpolate` in interface `Interpolatable<Pose2d>`
Parameters:
`endValue` - The upper bound, or end.
`t` - How far between the lower and upper bound we are. This should be bounded in [0, 1].
Returns:
The interpolated value.