Ellipsoid

Members

geocentricSurfaceNormal :DeveloperError

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

<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.

Throws:

DeveloperError : cartesians is required.

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 Cartesian(17832.12, 83234.52, 952313.73),
                 new Cartesian(17832.13, 83234.53, 952313.73),
                 new Cartesian(17832.14, 83234.54, 952313.73)]
var cartographicPositions = 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.

Throws:

DeveloperError : cartesian is required.

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 Cartesian(17832.12, 83234.52, 952313.73);
var cartographicPosition = 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.

Throws:

DeveloperError : cartographics is required.

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 Cartographic(Math.toRadians(21), Math.toRadians(78), 0),
                 new Cartographic(Math.toRadians(21.321), Math.toRadians(78.123), 100),
                 new Cartographic(Math.toRadians(21.645), Math.toRadians(78.456), 250)
var cartesianPositions = 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.

Throws:

DeveloperError : cartographic is required.

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 Cartographic(Math.toRadians(21), Math.toRadians(78), 5000);
var cartesianPosition = Ellipsoid.WGS84.cartographicToCartesian(position);

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.

Throws:

DeveloperError : cartesian is required.

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.

Throws:

DeveloperError : cartographic is required.

Returns:

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

getMaximumRadius

Returns:

Cartesian3 The maximum radius of the ellipsoid.

getMinimumRadius

Returns:

Cartesian3 The minimum radius of the ellipsoid.

getOneOverRadii

Returns:

Cartesian3 One over the radii of the ellipsoid.

getOneOverRadiiSquared

Returns:

Cartesian3 One over the squared radii of the ellipsoid.

getRadii

Returns:

Cartesian3 The radii of the ellipsoid.

getRadiiSquared

Returns:

Cartesian3 The squared radii of the ellipsoid.

getRadiiToTheFourth

Returns:

Cartesian3 The radii of the ellipsoid raised to the fourth power.

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.

Throws:

DeveloperError : cartesian is required.

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.

Throws:

DeveloperError : cartesian is required.

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)'.

transformPositionToScaledSpace

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

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.

<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.

Throws:

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

Returns:

Ellipsoid A new Ellipsoid instance.

See:

• Ellipsoid.WGS84
• Ellipsoid.UNIT_SPHERE