Ellipsoid - Cesium Documentation

new Ellipsoid

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.

Parameters:

Name	Type	Argument	Description
`x`	Number	<optional>	The radius in the x direction.
`y`	Number	<optional>	The radius in the y direction.
`z`	Number	<optional>	The radius in the z direction.

Throws:

DeveloperError : All radii components must be greater than or equal to zero.

See:

Source:

soid.js

Members

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.

<static> MOON

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

<static> UNIT_SPHERE

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

<static> WGS84

An Ellipsoid instance initialized to the WGS84 standard.

See:

czm_getWgs84EllipsoidEC

Methods

cartesianArrayToCartographicArray

Converts the provided array of cartesians to an array of cartographics.

Parameters:

Name	Type	Argument	Description
`cartesians`	Array		An array of Cartesian positions.
`result`	Array	<optional>	The object onto which to store the result.

Returns:

Array 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.Cartesian(17832.12, 83234.52, 952313.73),
                 new Cesium.Cartesian(17832.13, 83234.53, 952313.73),
                 new Cesium.Cartesian(17832.14, 83234.54, 952313.73)]
var cartographicPositions = Cesium.Ellipsoid.WGS84.cartesianArrayToCartographicArray(positions);

cartesianToCartographic

Converts the provided cartesian to cartographic representation. The cartesian is undefined at the center of the ellipsoid.

Parameters:

Name	Type	Argument	Description
`cartesian`	Cartesian3		The Cartesian position to convert to cartographic representation.
`result`	Cartographic	<optional>	The object onto which to store the result.

Returns:

Cartographic 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

Converts the provided array of cartographics to an array of Cartesians.

Parameters:

Name	Type	Argument	Description
`cartographics`	Array		An array of cartographic positions.
`result`	Array	<optional>	The object onto which to store the result.

Returns:

Array 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

Converts the provided cartographic to Cartesian representation.

Parameters:

Name	Type	Argument	Description
`cartographic`	Cartographic		The cartographic position.
`result`	Cartesian3	<optional>	The object onto which to store the result.

Returns:

Cartesian3 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

Duplicates an Ellipsoid instance.

Parameters:

Name	Type	Argument	Description
`result`	Ellipsoid	<optional>	The object onto which to store the result, or undefined if a new instance should be created.

Returns:

Ellipsoid The cloned Ellipsoid.

equals

Compares this Ellipsoid against the provided Ellipsoid componentwise and returns true if they are equal, false otherwise.

Parameters:

Name	Type	Argument	Description
`right`	Ellipsoid	<optional>	The other Ellipsoid.

Returns:

Boolean true if they are equal, false otherwise.

geodeticSurfaceNormal

Computes the normal of the plane tangent to the surface of the ellipsoid at the provided position.

Parameters:

Name	Type	Argument	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:

Cartesian3 The modified result parameter or a new Cartesian3 instance if none was provided.

geodeticSurfaceNormalCartographic

Computes the normal of the plane tangent to the surface of the ellipsoid at the provided position.

Parameters:

Name	Type	Argument	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:

Cartesian3 The modified result parameter or a new Cartesian3 instance if none was provided.

scaleToGeocentricSurface

Scales the provided Cartesian position along the geocentric surface normal so that it is on the surface of this ellipsoid.

Parameters:

Name	Type	Argument	Description
`cartesian`	Cartesian3		The Cartesian position to scale.
`result`	Cartesian3	<optional>	The object onto which to store the result.

Returns:

Cartesian3 The modified result parameter or a new Cartesian3 instance if none was provided.

scaleToGeodeticSurface

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.

Parameters:

Name	Type	Argument	Description
`cartesian`	Cartesian3		The Cartesian position to scale.
`result`	Cartesian3	<optional>	The object onto which to store the result.

Returns:

Cartesian3 The modified result parameter, a new Cartesian3 instance if none was provided, or undefined if the position is at the center.

toString

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

Returns:

String A string representing this ellipsoid in the format '(radii.x, radii.y, radii.z)'.

transformPositionFromScaledSpace

Transforms a Cartesian X, Y, Z position from the ellipsoid-scaled space by multiplying its components by the result of Ellipsoid#radii.

Parameters:

Name	Type	Argument	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:

Cartesian3 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

Transforms a Cartesian X, Y, Z position to the ellipsoid-scaled space by multiplying its components by the result of Ellipsoid#oneOverRadii.

Parameters:

Name	Type	Argument	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:

Cartesian3 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.

<static> clone

Duplicates an Ellipsoid instance.

Parameters:

Name	Type	Argument	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:

Ellipsoid The cloned Ellipsoid. (Returns undefined if ellipsoid is undefined)

<static> fromCartesian3

Computes an Ellipsoid from a Cartesian specifying the radii in x, y, and z directions.

Parameters:

Name	Type	Argument	Default	Description
`radii`	Cartesian3	<optional>	Cartesian3.ZERO	The ellipsoid's radius in the x, y, and z directions.