Ellipsoid

new Ellipsoid(x, y, z)

A quadratic surface defined in Cartesian coordinates by the equation (x / a)^2 + (y / b)^2 + (z / c)^2 = 1. Primarily used by Cesium to represent the shape of planetary bodies. Rather than constructing this object directly, one of the provided constants is normally used.
Name Type Default Description
x Number 0 optional The radius in the x direction.
y Number 0 optional The radius in the y direction.
z Number 0 optional The radius in the z direction.
Throws:
  • DeveloperError : All radii components must be greater than or equal to zero.
See:

Members

staticEllipsoid.MOON

An Ellipsoid instance initialized to a sphere with the lunar radius.

staticEllipsoid.UNIT_SPHERE

An Ellipsoid instance initialized to radii of (1.0, 1.0, 1.0).

staticEllipsoid.WGS84

An Ellipsoid instance initialized to the WGS84 standard.
See:
  • czm_getWgs84EllipsoidEC

geocentricSurfaceNormal

Computes the unit vector directed from the center of this ellipsoid toward the provided Cartesian position.

maximumRadius :Number

Gets the maximum radius of the ellipsoid.

minimumRadius :Number

Gets the minimum radius of the ellipsoid.

oneOverRadii :Cartesian3

Gets one over the radii of the ellipsoid.

oneOverRadiiSquared :Cartesian3

Gets one over the squared radii of the ellipsoid.

radii :Cartesian3

Gets the radii of the ellipsoid.

radiiSquared :Cartesian3

Gets the squared radii of the ellipsoid.

radiiToTheFourth :Cartesian3

Gets the radii of the ellipsoid raise to the fourth power.

Methods

staticEllipsoid.clone(ellipsoid, result)Ellipsoid

Duplicates an Ellipsoid instance.
Name Type Description
ellipsoid Ellipsoid The ellipsoid to duplicate.
result Ellipsoid optional The object onto which to store the result, or undefined if a new instance should be created.
Returns:
The cloned Ellipsoid. (Returns undefined if ellipsoid is undefined)

staticEllipsoid.fromCartesian3(radii)Ellipsoid

Computes an Ellipsoid from a Cartesian specifying the radii in x, y, and z directions.
Name Type Default Description
radii Cartesian3 Cartesian3.ZERO optional The ellipsoid's radius in the x, y, and z directions.
Returns:
A new Ellipsoid instance.
Throws:
  • DeveloperError : All radii components must be greater than or equal to zero.
See:

cartesianArrayToCartographicArray(cartesians, result)Cartographic[]

Converts the provided array of cartesians to an array of cartographics.
Name Type Description
cartesians Cartesian3[] An array of Cartesian positions.
result Cartographic[] optional The object onto which to store the result.
Returns:
The modified result parameter or a new Array instance if none was provided.
Example:
//Create an array of Cartesians and determine their Cartographic representation on a WGS84 ellipsoid.
var positions = [new Cesium.Cartesian3(17832.12, 83234.52, 952313.73),
                 new Cesium.Cartesian3(17832.13, 83234.53, 952313.73),
                 new Cesium.Cartesian3(17832.14, 83234.54, 952313.73)]
var cartographicPositions = Cesium.Ellipsoid.WGS84.cartesianArrayToCartographicArray(positions);

cartesianToCartographic(cartesian, result)Cartographic

Converts the provided cartesian to cartographic representation. The cartesian is undefined at the center of the ellipsoid.
Name Type Description
cartesian Cartesian3 The Cartesian position to convert to cartographic representation.
result Cartographic optional The object onto which to store the result.
Returns:
The modified result parameter, new Cartographic instance if none was provided, or undefined if the cartesian is at the center of the ellipsoid.
Example:
//Create a Cartesian and determine it's Cartographic representation on a WGS84 ellipsoid.
var position = new Cesium.Cartesian(17832.12, 83234.52, 952313.73);
var cartographicPosition = Cesium.Ellipsoid.WGS84.cartesianToCartographic(position);

cartographicArrayToCartesianArray(cartographics, result)Cartesian3[]

Converts the provided array of cartographics to an array of Cartesians.
Name Type Description
cartographics Cartographic[] An array of cartographic positions.
result Cartesian3[] optional The object onto which to store the result.
Returns:
The modified result parameter or a new Array instance if none was provided.
Example:
//Convert an array of Cartographics and determine their Cartesian representation on a WGS84 ellipsoid.
var positions = [new Cesium.Cartographic(Cesium.Math.toRadians(21), Cesium.Math.toRadians(78), 0),
                 new Cesium.Cartographic(Cesium.Math.toRadians(21.321), Cesium.Math.toRadians(78.123), 100),
                 new Cesium.Cartographic(Cesium.Math.toRadians(21.645), Cesium.Math.toRadians(78.456), 250)
var cartesianPositions = Cesium.Ellipsoid.WGS84.cartographicArrayToCartesianArray(positions);

cartographicToCartesian(cartographic, result)Cartesian3

Converts the provided cartographic to Cartesian representation.
Name Type Description
cartographic Cartographic The cartographic position.
result Cartesian3 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Cartesian3 instance if none was provided.
Example:
//Create a Cartographic and determine it's Cartesian representation on a WGS84 ellipsoid.
var position = new Cesium.Cartographic(Cesium.Math.toRadians(21), Cesium.Math.toRadians(78), 5000);
var cartesianPosition = Cesium.Ellipsoid.WGS84.cartographicToCartesian(position);

clone(result)Ellipsoid

Duplicates an Ellipsoid instance.
Name Type Description
result Ellipsoid optional The object onto which to store the result, or undefined if a new instance should be created.
Returns:
The cloned Ellipsoid.

equals(right)Boolean

Compares this Ellipsoid against the provided Ellipsoid componentwise and returns true if they are equal, false otherwise.
Name Type Description
right Ellipsoid optional The other Ellipsoid.
Returns:
true if they are equal, false otherwise.

geodeticSurfaceNormal(cartesian, result)Cartesian3

Computes the normal of the plane tangent to the surface of the ellipsoid at the provided position.
Name Type Description
cartesian Cartesian3 The Cartesian position for which to to determine the surface normal.
result Cartesian3 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Cartesian3 instance if none was provided.

geodeticSurfaceNormalCartographic(cartographic, result)Cartesian3

Computes the normal of the plane tangent to the surface of the ellipsoid at the provided position.
Name Type Description
cartographic Cartographic The cartographic position for which to to determine the geodetic normal.
result Cartesian3 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Cartesian3 instance if none was provided.

scaleToGeocentricSurface(cartesian, result)Cartesian3

Scales the provided Cartesian position along the geocentric surface normal so that it is on the surface of this ellipsoid.
Name Type Description
cartesian Cartesian3 The Cartesian position to scale.
result Cartesian3 optional The object onto which to store the result.
Returns:
The modified result parameter or a new Cartesian3 instance if none was provided.

scaleToGeodeticSurface(cartesian, result)Cartesian3

Scales the provided Cartesian position along the geodetic surface normal so that it is on the surface of this ellipsoid. If the position is at the center of the ellipsoid, this function returns undefined.
Name Type Description
cartesian Cartesian3 The Cartesian position to scale.
result Cartesian3 optional The object onto which to store the result.
Returns:
The modified result parameter, a new Cartesian3 instance if none was provided, or undefined if the position is at the center.

toString()String

Creates a string representing this Ellipsoid in the format '(radii.x, radii.y, radii.z)'.
Returns:
A string representing this ellipsoid in the format '(radii.x, radii.y, radii.z)'.

transformPositionFromScaledSpace(position, result)Cartesian3

Transforms a Cartesian X, Y, Z position from the ellipsoid-scaled space by multiplying its components by the result of Ellipsoid#radii.
Name Type Description
position Cartesian3 The position to transform.
result Cartesian3 optional The position to which to copy the result, or undefined to create and return a new instance.
Returns:
The position expressed in the unscaled space. The returned instance is the one passed as the result parameter if it is not undefined, or a new instance of it is.

transformPositionToScaledSpace(position, result)Cartesian3

Transforms a Cartesian X, Y, Z position to the ellipsoid-scaled space by multiplying its components by the result of Ellipsoid#oneOverRadii.
Name Type Description
position Cartesian3 The position to transform.
result Cartesian3 optional The position to which to copy the result, or undefined to create and return a new instance.
Returns:
The position expressed in the scaled space. The returned instance is the one passed as the result parameter if it is not undefined, or a new instance of it is.