OrbPro2 a Cesium distribution

Transforms

engine/Source/Core/Transforms.js 22
Contains functions for transforming positions to various reference frames.

Methods

static Cesium.Transforms.computeFixedToIcrfMatrix(date, result) → Matrix3|undefined
engine/Source/Core/Transforms.js 895

Computes a rotation matrix to transform a point or vector from the Earth-Fixed frame axes (ITRF) to the International Celestial Reference Frame (GCRF/ICRF) inertial frame axes at a given time. This function may return undefined if the data necessary to do the transformation is not yet loaded.
Name Type Description
date JulianDate The time at which to compute the rotation matrix.
result Matrix3 optional The object onto which to store the result. If this parameter is not specified, a new instance is created and returned.
Returns:
The rotation matrix, or undefined if the data necessary to do the transformation is not yet loaded.
Example:
// Transform a point from the Fixed axes to the ICRF axes.
const now = Cesium.JulianDate.now();
const pointInFixed = Cesium.Cartesian3.fromDegrees(0.0, 0.0);
const fixedToIcrf = Cesium.Transforms.computeFixedToIcrfMatrix(now);
let pointInInertial = new Cesium.Cartesian3();
if (Cesium.defined(fixedToIcrf)) {
    pointInInertial = Cesium.Matrix3.multiplyByVector(fixedToIcrf, pointInFixed, pointInInertial);
}
See:

static Cesium.Transforms.computeIcrfToCentralBodyFixedMatrix(date, result) → Matrix3|undefined
engine/Source/Core/Transforms.js 555

The default function to compute a rotation matrix to transform a point or vector from the International Celestial Reference Frame (GCRF/ICRF) inertial frame axes to the central body, typically Earth, fixed frame axis at a given time for use in lighting and transformation from inertial reference frames. This function may return undefined if the data necessary to do the transformation is not yet loaded.
Name Type Description
date JulianDate The time at which to compute the rotation matrix.
result Matrix3 optional The object onto which to store the result. If this parameter is not specified, a new instance is created and returned.
Returns:
The rotation matrix, or undefined if the data necessary to do the transformation is not yet loaded.
Example:
// Set the default ICRF to fixed transformation to that of the Moon.
Cesium.Transforms.computeIcrfToCentralBodyFixedMatrix = Cesium.Transforms.computeIcrfToMoonFixedMatrix;
See:

static Cesium.Transforms.computeIcrfToFixedMatrix(date, result) → Matrix3|undefined
engine/Source/Core/Transforms.js 734

Computes a rotation matrix to transform a point or vector from the International Celestial Reference Frame (GCRF/ICRF) inertial frame axes to the Earth-Fixed frame axes (ITRF) at a given time. This function may return undefined if the data necessary to do the transformation is not yet loaded.
Name Type Description
date JulianDate The time at which to compute the rotation matrix.
result Matrix3 optional The object onto which to store the result. If this parameter is not specified, a new instance is created and returned.
Returns:
The rotation matrix, or undefined if the data necessary to do the transformation is not yet loaded.
Example:
scene.postUpdate.addEventListener(function(scene, time) {
  // View in ICRF.
  const icrfToFixed = Cesium.Transforms.computeIcrfToFixedMatrix(time);
  if (Cesium.defined(icrfToFixed)) {
    const offset = Cesium.Cartesian3.clone(camera.position);
    const transform = Cesium.Matrix4.fromRotationTranslation(icrfToFixed);
    camera.lookAtTransform(transform, offset);
  }
});
See:

static Cesium.Transforms.computeIcrfToMoonFixedMatrix(date, result) → Matrix3
engine/Source/Core/Transforms.js 840

Computes a rotation matrix to transform a point or vector from the International Celestial Reference Frame (GCRF/ICRF) inertial frame axes to the Moon-Fixed frame axes at a given time.
Name Type Description
date JulianDate The time at which to compute the rotation matrix.
result Matrix3 optional The object onto which to store the result. If this parameter is not specified, a new instance is created and returned.
Returns:
The rotation matrix.
Example:
// Set the default ICRF to fixed transformation to that of the Moon.
Cesium.Transforms.computeIcrfToCentralBodyFixedMatrix = Cesium.Transforms.computeIcrfToMoonFixedMatrix;

static Cesium.Transforms.computeMoonFixedToIcrfMatrix(date, result) → Matrix3
engine/Source/Core/Transforms.js 778

Computes a rotation matrix to transform a point or vector from the Moon-Fixed frame axes to the International Celestial Reference Frame (GCRF/ICRF) inertial frame axes at a given time.
Name Type Description
date JulianDate The time at which to compute the rotation matrix.
result Matrix3 optional The object onto which to store the result. If this parameter is not specified, a new instance is created and returned.
Returns:
The rotation matrix.
Example:
// Transform a point from the Fixed axes to the ICRF axes.
const now = Cesium.JulianDate.now();
const pointInFixed = Cesium.Cartesian3.fromDegrees(0.0, 0.0);
const fixedToIcrf = Cesium.Transforms.computeMoonFixedToIcrfMatrix(now);
let pointInInertial = new Cesium.Cartesian3();
if (Cesium.defined(fixedToIcrf)) {
    pointInInertial = Cesium.Matrix3.multiplyByVector(fixedToIcrf, pointInFixed, pointInInertial);
}

static Cesium.Transforms.computeTemeToPseudoFixedMatrix(date, result) → Matrix3
engine/Source/Core/Transforms.js 583

Computes a rotation matrix to transform a point or vector from True Equator Mean Equinox (TEME) axes to the pseudo-fixed axes at a given time. This method treats the UT1 time standard as equivalent to UTC.
Name Type Description
date JulianDate The time at which to compute the rotation matrix.
result Matrix3 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Matrix3 instance if none was provided.
Example:
//Set the view to the inertial frame.
scene.postUpdate.addEventListener(function(scene, time) {
   const now = Cesium.JulianDate.now();
   const offset = Cesium.Matrix4.multiplyByPoint(camera.transform, camera.position, new Cesium.Cartesian3());
   const transform = Cesium.Matrix4.fromRotationTranslation(Cesium.Transforms.computeTemeToPseudoFixedMatrix(now));
   const inverseTransform = Cesium.Matrix4.inverseTransformation(transform, new Cesium.Matrix4());
   Cesium.Matrix4.multiplyByPoint(inverseTransform, offset, offset);
   camera.lookAtTransform(transform, offset);
});

static Cesium.Transforms.eastNorthUpToFixedFrame(origin, ellipsoid, result) → Matrix4
engine/Source/Core/Transforms.js 277

Computes a 4x4 transformation matrix from a reference frame with an east-north-up axes centered at the provided origin to the provided ellipsoid's fixed reference frame. The local axes are defined as:
  • The x axis points in the local east direction.
  • The y axis points in the local north direction.
  • The z axis points in the direction of the ellipsoid surface normal which passes through the position.
Name Type Default Description
origin Cartesian3 The center point of the local reference frame.
ellipsoid Ellipsoid Ellipsoid.default optional The ellipsoid whose fixed frame is used in the transformation.
result Matrix4 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Matrix4 instance if none was provided.
Example:
// Get the transform from local east-north-up at cartographic (0.0, 0.0) to Earth's fixed frame.
const center = Cesium.Cartesian3.fromDegrees(0.0, 0.0);
const transform = Cesium.Transforms.eastNorthUpToFixedFrame(center);

static Cesium.Transforms.fixedFrameToHeadingPitchRoll(transform, ellipsoid, fixedFrameTransform, result) → HeadingPitchRoll
engine/Source/Core/Transforms.js 478

Computes heading-pitch-roll angles from a transform in a particular reference frame. Heading is the rotation from the local east direction where a positive angle is increasing eastward. Pitch is the rotation from the local east-north plane. Positive pitch angles are above the plane. Negative pitch angles are below the plane. Roll is the first rotation applied about the local east axis.
Name Type Default Description
transform Matrix4 The transform
ellipsoid Ellipsoid Ellipsoid.default optional The ellipsoid whose fixed frame is used in the transformation.
fixedFrameTransform Transforms.LocalFrameToFixedFrame Transforms.eastNorthUpToFixedFrame optional A 4x4 transformation matrix from a reference frame to the provided ellipsoid's fixed reference frame
result HeadingPitchRoll optional The object onto which to store the result.
Returns:
The modified result parameter or a new HeadingPitchRoll instance if none was provided.

static Cesium.Transforms.getPositionInVVLH(entity, referenceEntity, time, currentTime, referenceFrame) → Cartesian3
engine/Source/Core/Transforms.js 1490

Computes an entity's position relative to a reference entity's VVLH frame, projected back into the fixed (or inertial) frame at the current time. Used for visualizing relative motion (proximity operations, rendezvous).
Name Type Default Description
entity Entity The entity whose position to compute.
referenceEntity Entity The reference entity defining the VVLH frame.
time JulianDate The sample time.
currentTime JulianDate The current display time (for projecting back to ECEF).
referenceFrame ReferenceFrame ReferenceFrame.FIXED optional The coordinate frame for position retrieval.
Returns:
The entity position in the reference entity's local frame, projected to ECEF.

static Cesium.Transforms.getTransformToFixedFrame(referenceFrame, time, positionProperty) → Transforms.LocalFrameToFixedFrame
engine/Source/Core/Transforms.js 1603

Returns a transform function that converts from the specified reference frame to the fixed frame.
Name Type Description
referenceFrame ReferenceFrame The reference frame.
time JulianDate optional The time (required for VVLH/LVLH/RIC frames).
positionProperty PositionProperty optional The position property (required for VVLH/LVLH/RIC frames).
Returns:
A function that computes the transform.

static Cesium.Transforms.headingPitchRollQuaternion(origin, headingPitchRoll, ellipsoid, fixedFrameTransform, result) → Quaternion
engine/Source/Core/Transforms.js 438

Computes a quaternion from a reference frame with axes computed from the heading-pitch-roll angles centered at the provided origin. Heading is the rotation from the local east direction where a positive angle is increasing eastward. Pitch is the rotation from the local east-north plane. Positive pitch angles are above the plane. Negative pitch angles are below the plane. Roll is the first rotation applied about the local east axis.
Name Type Default Description
origin Cartesian3 The center point of the local reference frame.
headingPitchRoll HeadingPitchRoll The heading, pitch, and roll.
ellipsoid Ellipsoid Ellipsoid.default optional The ellipsoid whose fixed frame is used in the transformation.
fixedFrameTransform Transforms.LocalFrameToFixedFrame Transforms.eastNorthUpToFixedFrame optional A 4x4 transformation matrix from a reference frame to the provided ellipsoid's fixed reference frame
result Quaternion optional The object onto which to store the result.
Returns:
The modified result parameter or a new Quaternion instance if none was provided.
Example:
// Get the quaternion from local heading-pitch-roll at cartographic (0.0, 0.0) to Earth's fixed frame.
const center = Cesium.Cartesian3.fromDegrees(0.0, 0.0);
const heading = -Cesium.Math.PI_OVER_TWO;
const pitch = Cesium.Math.PI_OVER_FOUR;
const roll = 0.0;
const hpr = new HeadingPitchRoll(heading, pitch, roll);
const quaternion = Cesium.Transforms.headingPitchRollQuaternion(center, hpr);

static Cesium.Transforms.headingPitchRollToFixedFrame(origin, headingPitchRoll, ellipsoid, fixedFrameTransform, result) → Matrix4
engine/Source/Core/Transforms.js 385

Computes a 4x4 transformation matrix from a reference frame with axes computed from the heading-pitch-roll angles centered at the provided origin to the provided ellipsoid's fixed reference frame. Heading is the rotation from the local east direction where a positive angle is increasing eastward. Pitch is the rotation from the local east-north plane. Positive pitch angles are above the plane. Negative pitch angles are below the plane. Roll is the first rotation applied about the local east axis.
Name Type Default Description
origin Cartesian3 The center point of the local reference frame.
headingPitchRoll HeadingPitchRoll The heading, pitch, and roll.
ellipsoid Ellipsoid Ellipsoid.default optional The ellipsoid whose fixed frame is used in the transformation.
fixedFrameTransform Transforms.LocalFrameToFixedFrame Transforms.eastNorthUpToFixedFrame optional A 4x4 transformation matrix from a reference frame to the provided ellipsoid's fixed reference frame
result Matrix4 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Matrix4 instance if none was provided.
Example:
// Get the transform from local heading-pitch-roll at cartographic (0.0, 0.0) to Earth's fixed frame.
const center = Cesium.Cartesian3.fromDegrees(0.0, 0.0);
const heading = -Cesium.Math.PI_OVER_TWO;
const pitch = Cesium.Math.PI_OVER_FOUR;
const roll = 0.0;
const hpr = new Cesium.HeadingPitchRoll(heading, pitch, roll);
const transform = Cesium.Transforms.headingPitchRollToFixedFrame(center, hpr);

static Cesium.Transforms.localFrameToFixedFrameGenerator(firstAxis, secondAxis) → Transforms.LocalFrameToFixedFrame
engine/Source/Core/Transforms.js 100

Generates a function that computes a 4x4 transformation matrix from a reference frame centered at the provided origin to the provided ellipsoid's fixed reference frame.
Name Type Description
firstAxis string name of the first axis of the local reference frame. Must be 'east', 'north', 'up', 'west', 'south' or 'down'.
secondAxis string name of the second axis of the local reference frame. Must be 'east', 'north', 'up', 'west', 'south' or 'down'.
Returns:
The function that will computes a 4x4 transformation matrix from a reference frame, with first axis and second axis compliant with the parameters,

static Cesium.Transforms.localToFixedFrameQuaternion(origin, localQuaternion, ellipsoid, fixedFrameTransform, result) → Quaternion
engine/Source/Core/Transforms.js 1425

Converts a quaternion expressed in a local reference frame to the fixed frame.
Name Type Description
origin Cartesian3 The origin position in the fixed frame.
localQuaternion Quaternion The quaternion in the local frame.
ellipsoid Ellipsoid The ellipsoid.
fixedFrameTransform Transforms.LocalFrameToFixedFrame The transform function from local to fixed frame.
result Quaternion optional The object onto which to store the result.
Returns:
The quaternion in the fixed frame.

static Cesium.Transforms.lvlhToFixed(positionProperty, time, result, deltaFactor) → Matrix4
engine/Source/Core/Transforms.js 1409

Computes a 4x4 transformation matrix from a LVLH (Local Vertical Local Horizontal) reference frame centered at the given position to the fixed frame. This is an alias for Transforms.vvlhToFixed as LVLH and VVLH are equivalent for the purposes of this implementation.
Name Type Default Description
positionProperty PositionProperty | SampledPositionProperty A position property that can be sampled.
time JulianDate The time at which to compute the frame.
result Matrix4 optional The object onto which to store the result.
deltaFactor number 0.01 optional Time delta in seconds for computing velocity.
Returns:
The modified result parameter or a new Matrix4 instance if none was provided.

static Cesium.Transforms.northEastDownToFixedFrame(origin, ellipsoid, result) → Matrix4
engine/Source/Core/Transforms.js 303

Computes a 4x4 transformation matrix from a reference frame with an north-east-down axes centered at the provided origin to the provided ellipsoid's fixed reference frame. The local axes are defined as:
  • The x axis points in the local north direction.
  • The y axis points in the local east direction.
  • The z axis points in the opposite direction of the ellipsoid surface normal which passes through the position.
Name Type Default Description
origin Cartesian3 The center point of the local reference frame.
ellipsoid Ellipsoid Ellipsoid.default optional The ellipsoid whose fixed frame is used in the transformation.
result Matrix4 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Matrix4 instance if none was provided.
Example:
// Get the transform from local north-east-down at cartographic (0.0, 0.0) to Earth's fixed frame.
const center = Cesium.Cartesian3.fromDegrees(0.0, 0.0);
const transform = Cesium.Transforms.northEastDownToFixedFrame(center);

static Cesium.Transforms.northUpEastToFixedFrame(origin, ellipsoid, result) → Matrix4
engine/Source/Core/Transforms.js 327

Computes a 4x4 transformation matrix from a reference frame with an north-up-east axes centered at the provided origin to the provided ellipsoid's fixed reference frame. The local axes are defined as:
  • The x axis points in the local north direction.
  • The y axis points in the direction of the ellipsoid surface normal which passes through the position.
  • The z axis points in the local east direction.
Name Type Default Description
origin Cartesian3 The center point of the local reference frame.
ellipsoid Ellipsoid Ellipsoid.default optional The ellipsoid whose fixed frame is used in the transformation.
result Matrix4 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Matrix4 instance if none was provided.
Example:
// Get the transform from local north-up-east at cartographic (0.0, 0.0) to Earth's fixed frame.
const center = Cesium.Cartesian3.fromDegrees(0.0, 0.0);
const transform = Cesium.Transforms.northUpEastToFixedFrame(center);

static Cesium.Transforms.northWestUpToFixedFrame(origin, ellipsoid, result) → Matrix4
engine/Source/Core/Transforms.js 353

Computes a 4x4 transformation matrix from a reference frame with an north-west-up axes centered at the provided origin to the provided ellipsoid's fixed reference frame. The local axes are defined as:
  • The x axis points in the local north direction.
  • The y axis points in the local west direction.
  • The z axis points in the direction of the ellipsoid surface normal which passes through the position.
Name Type Default Description
origin Cartesian3 The center point of the local reference frame.
ellipsoid Ellipsoid Ellipsoid.default optional The ellipsoid whose fixed frame is used in the transformation.
result Matrix4 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Matrix4 instance if none was provided.
Example:
// Get the transform from local north-West-Up at cartographic (0.0, 0.0) to Earth's fixed frame.
const center = Cesium.Cartesian3.fromDegrees(0.0, 0.0);
const transform = Cesium.Transforms.northWestUpToFixedFrame(center);

static Cesium.Transforms.pointToWindowCoordinates(modelViewProjectionMatrix, viewportTransformation, point, result) → Cartesian2
engine/Source/Core/Transforms.js 1018

Transform a point from model coordinates to window coordinates.
Name Type Description
modelViewProjectionMatrix Matrix4 The 4x4 model-view-projection matrix.
viewportTransformation Matrix4 The 4x4 viewport transformation.
point Cartesian3 The point to transform.
result Cartesian2 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Cartesian2 instance if none was provided.

static Cesium.Transforms.preloadIcrfFixed(timeInterval) → Promise.<void>
engine/Source/Core/Transforms.js 694

Preloads the data necessary to transform between the ICRF and Fixed axes, in either direction, over a given interval. This function returns a promise that, when resolved, indicates that the preload has completed.
Name Type Description
timeInterval TimeInterval The interval to preload.
Returns:
A promise that, when resolved, indicates that the preload has completed and evaluation of the transformation between the fixed and ICRF axes will no longer return undefined for a time inside the interval.
Example:
const interval = new Cesium.TimeInterval(...);
await Cesium.Transforms.preloadIcrfFixed(interval));
// the data is now loaded
See:

static Cesium.Transforms.rotationMatrixFromPositionVelocity(position, velocity, ellipsoid, result) → Matrix3
engine/Source/Core/Transforms.js 1086

Transform a position and velocity to a rotation matrix.
Name Type Default Description
position Cartesian3 The position to transform.
velocity Cartesian3 The velocity vector to transform.
ellipsoid Ellipsoid Ellipsoid.default optional The ellipsoid whose fixed frame is used in the transformation.
result Matrix3 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Matrix3 instance if none was provided.

static Cesium.Transforms.vvlhToFixed(positionProperty, time, result, deltaFactor) → Matrix4
engine/Source/Core/Transforms.js 1301

Computes a 4x4 transformation matrix from a VVLH (Vehicle Velocity Local Horizontal) reference frame centered at the given position to the fixed frame. The VVLH frame is velocity-aligned: - X-axis: Velocity direction (in-track/forward) - Y-axis: Cross-track (perpendicular to orbit plane, angular momentum direction) - Z-axis: Radial out (away from Earth center)
Name Type Default Description
positionProperty PositionProperty | SampledPositionProperty A position property that can be sampled.
time JulianDate The time at which to compute the frame.
result Matrix4 optional The object onto which to store the result.
deltaFactor number 0.01 optional Time delta in seconds for computing velocity.
Returns:
The modified result parameter or a new Matrix4 instance if none was provided.

Type Definitions

Cesium.Transforms.LocalFrameToFixedFrame(origin, ellipsoid, result) → Matrix4
engine/Source/Core/Transforms.js 111

Computes a 4x4 transformation matrix from a reference frame centered at the provided origin to the provided ellipsoid's fixed reference frame.
Name Type Default Description
origin Cartesian3 The center point of the local reference frame.
ellipsoid Ellipsoid Ellipsoid.default optional The ellipsoid whose fixed frame is used in the transformation.
result Matrix4 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Matrix4 instance if none was provided.
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