LinearSpline - Cesium Documentation

# LinearSpline

#### new LinearSpline()

  A spline that uses piecewise linear interpolation to create a curve.

  Name | Type | Description
  --- | --- | ---
  `options.times` | Array.<Number> | An array of strictly increasing, unit-less, floating-point times at each point. The values are in no way connected to the clock time. They are the parameterization for the curve.
  `options.points` | Array.<Cartesian3> | The array of `Cartesian3` control points.

  ##### Throws:

  - DeveloperError : points.length must be greater than or equal to 2.
  - DeveloperError : times.length must be equal to points.length.

  ##### Example:

      var spline = new Cesium.LinearSpline({
          times : [ 0.0, 1.5, 3.0, 4.5, 6.0 ],
          points : [
              new Cesium.Cartesian3(1235398.0, -4810983.0, 4146266.0),
              new Cesium.Cartesian3(1372574.0, -5345182.0, 4606657.0),
              new Cesium.Cartesian3(-757983.0, -5542796.0, 4514323.0),
              new Cesium.Cartesian3(-2821260.0, -5248423.0, 4021290.0),
              new Cesium.Cartesian3(-2539788.0, -4724797.0, 3620093.0)
          ]
      });

      var p0 = spline.evaluate(times[i]);         // equal to positions[i]
      var p1 = spline.evaluate(times[i] + delta); // interpolated value when delta < times[i + 1] - times[i]

  ##### See:

  - HermiteSpline
  - CatmullRomSpline
  - QuaternionSpline
  Source: Core/LinearSpline.js, line 50

### Members

#### readonlypoints :Array.<Cartesian3>

  An array of `Cartesian3` control points.
  Source: Core/LinearSpline.js, line 97

#### readonlytimes :Array.<Number>

  An array of times for the control points.
  Source: Core/LinearSpline.js, line 83

### Methods

#### evaluate(time, result) → Cartesian3

  Evaluates the curve at a given time.

  Name | Type | Description
  --- | --- | ---
  `time` | Number | The time at which to evaluate the curve.
  `result` | Cartesian3 | optional The object onto which to store the result.

  ##### Returns:

  The modified result parameter or a new instance of the point on the curve at the given time.

  ##### Throws:

  - DeveloperError : time must be in the range `[t0, tn]`, where `t0` is the first element in the array `times` and `tn` is the last element in the array `times`.
  Source: Core/LinearSpline.js, line 129

#### findTimeInterval(time) → Number

  Finds an index `i` in `times` such that the parameter `time` is in the interval `[times[i], times[i + 1]]`.

  Name | Type | Description
  --- | --- | ---
  `time` | Number | The time.

  ##### Returns:

  The index for the element at the start of the interval.

  ##### Throws:

  - DeveloperError : time must be in the range `[t0, tn]`, where `t0` is the first element in the array `times` and `tn` is the last element in the array `times`.
  Source: Core/LinearSpline.js, line 116