# VelocityVectorProperty

#### new Cesium.VelocityVectorProperty(position, normalize)
DataSources/VelocityVectorProperty.js 44

  A `Property` which evaluates to a `Cartesian3` vector based on the velocity of the provided `PositionProperty`.

  Name | Type | Default | Description
  --- | --- | --- | ---
  `position` | Property |  | optional The position property used to compute the velocity.
  `normalize` | Boolean | `true` | optional Whether to normalize the computed velocity vector.

  ##### Example:

      //Create an entity with a billboard rotated to match its velocity.
      var position = new Cesium.SampledProperty();
      position.addSamples(...);
      var entity = viewer.entities.add({
        position : position,
        billboard : {
          image : 'image.png',
          alignedAxis : new Cesium.VelocityVectorProperty(position, true) // alignedAxis must be a unit vector
        }
      }));

### Members

#### readonlydefinitionChanged : Event
DataSources/VelocityVectorProperty.js 73

  Gets the event that is raised whenever the definition of this property changes.

#### readonlyisConstant : Boolean
DataSources/VelocityVectorProperty.js 61

  Gets a value indicating if this property is constant.

#### normalize : Boolean
DataSources/VelocityVectorProperty.js 114

  Gets or sets whether the vector produced by this property will be normalized or not.

#### position : Property
DataSources/VelocityVectorProperty.js 84

  Gets or sets the position property used to compute the velocity vector.

### Methods

#### equals(other) → Boolean
DataSources/VelocityVectorProperty.js 205

  Compares this property to the provided property and returns `true` if they are equal, `false` otherwise.

  Name | Type | Description
  --- | --- | ---
  `other` | Property | optional The other property.

  ##### Returns:

  `true` if left and right are equal, `false` otherwise.

#### getValue(time, result) → Cartesian3
DataSources/VelocityVectorProperty.js 141

  Gets the value of the property at the provided time.

  Name | Type | Description
  --- | --- | ---
  `time` | JulianDate | optional The time for which to retrieve the value.
  `result` | Cartesian3 | optional The object to store the value into, if omitted, a new instance is created and returned.

  ##### Returns:

  The modified result parameter or a new instance if the result parameter was not supplied.