Class Ellipsoid

A configurable spheroid that allows conversion from and to geodetic coordinates and cartesian coordinates, as well as utility function to compute various geodetic values.

Constructors

constructor

Accessors

compressionFactor

eccentricity

equatorialCircumference

flattening

semiMajorAxis

semiMinorAxis

StaticWGS84

Methods

getEastNorthUpMatrix

  • getEastNorthUpMatrix(lat, lon, target?): Matrix4

  • Gets the ENU (east/north/up) matrix for the given location in geodetic coordinates.

    Parameters

    • lat: number
    • lon: number
    • Optionaltarget: Matrix4

      The optional matrix to set with the ENU matrix.

    Returns Matrix4

    The ENU matrix.

getEastNorthUpMatrixFromCartesian

  • getEastNorthUpMatrixFromCartesian(point, target?): Matrix4

  • Gets the ENU (east/north/up) matrix for the given location.

    Parameters

    • point: Readonly<Vector3>

      The cartesian coordinate in the geocentric system of this ellipsoid.

    • Optionaltarget: Matrix4

      The optional matrix to set with the ENU matrix.

    Returns Matrix4

    The ENU matrix.

getExtentDimensions

  • getExtentDimensions(extent, target?): Vector2

  • Gets the dimensions (width and height) across the center of of the extent, in meters.

    Note: this is distinct to Extent.dimensions which returns the dimensions in the extent's own CRS (meters or degrees).

    Parameters

    • extent: Extent

      The extent.

    • Optionaltarget: Vector2

      The object to store the result. If none, one will be created.

    Returns Vector2

    The extent dimensions.

    Throws

    if the extent is not in the EPSG:4326 CRS.

getMeridianArcLength

  • getMeridianArcLength(latitude0, latitude1): number

  • Returns an approximated length of the meridian arc of the given angle, in meters.

    Note: this function uses a very simplified method, as the actual method involves intrgrals. For very oblate spheroids, the results will be wrong.

    Parameters

    • latitude0: number

      The latitude of the start of the meridian arc

    • latitude1: number

      The latitude of the end of the meridian arc

    Returns number

getNormal

  • getNormal(lat, lon, target?): Vector3

  • Returns the normal of the spheroid for the given location.

    Parameters

    • lat: number

      The latitude, in degrees.

    • lon: number

      The longitude, in degrees.

    • Optionaltarget: Vector3

      The target vector to store the result. If none, one will be created.

    Returns Vector3

    The normal vector.

getNormalFromCartesian

  • getNormalFromCartesian(cartesian, target?): Vector3

  • Returns the normal of the spheroid for the given cartesian coordinate.

    Parameters

    • cartesian: Readonly<Vector3>

      The cartesian coordinates.

    • Optionaltarget: Vector3

      The target vector to store the result. If none, one will be created.

    Returns Vector3

    The normal vector.

getOpticalHorizon

  • getOpticalHorizon(cameraPosition, center?): null | number

  • Gets the distance to the horizon given a camera position.

    Parameters

    • cameraPosition: Vector3

      The camera position.

    • Optionalcenter: Vector3

      The center of the ellipsoid (by default (0, 0, 0)).

    Returns null | number

    The distance, in meters, from the camera to the horizon.

getParallelArcLength

  • getParallelArcLength(latitude, angle): number

  • Returns the length of the parallel arc of the given angle, in meters.

    Parameters

    • latitude: number

      The latitude of the parallel.

    • angle: number

      The angle of the arc in degrees.

    Returns number

grow

intersectRay

  • intersectRay(ray, target?): null | Vector3

  • Returns the first intersection of the ray with the ellipsoid, or null if the ray does not intersect the ellipsoid.

    Parameters

    • ray: Ray

      The ray to intersect.

    • Optionaltarget: Vector3

      The optional vector to store the result.

    Returns null | Vector3

    The intersection or null if not intersection was found.

isHorizonVisible

  • isHorizonVisible(cameraPosition, point, radiusFactor?): boolean

  • Determine whether the given point is visible from the camera or occluded by the horizon of this ellipsoid.

    Parameters

    • cameraPosition: Vector3

      The camera position, in world space coordinates.

    • point: Vector3

      The point to test, in world space coordinates.

    • radiusFactor: number = 1

      An optional factor to apply to ellipsoid radii to add a margin of error.

    Returns boolean

    true if the given point is above the horizon, false otherwise.

scale

toCartesian

  • toCartesian(lat, lon, alt, target?): Vector3

  • Converts the geodetic coordinates to cartesian coordinates in the ECEF coordinate system.

    Parameters

    • lat: number

      The latitude, in degrees.

    • lon: number

      The longitude, in degrees.

    • alt: number

      The altitude, in meters, above or below the ellipsoid.

    • Optionaltarget: Vector3

      The target vector. If none, one will be created.

    Returns Vector3

    The cartesian coordinates.

toGeodetic

  • toGeodetic(x, y, z, target?): Coordinates

  • Converts the cartesian coordinates to geodetic coordinates.

    Parameters

    • x: number

      The cartesian X coordinate.

    • y: number

      The cartesian Y coordinate.

    • z: number

      The cartesian Z coordinate.

    • Optionaltarget: Coordinates

    Returns Coordinates

    The geodetic coordinates.

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