WebMercatorProjection

new Cesium.WebMercatorProjection(ellipsoid)

The map projection used by Google Maps, Bing Maps, and most of ArcGIS Online, EPSG:3857. This projection use longitude and latitude expressed with the WGS84 and transforms them to Mercator using the spherical (rather than ellipsoidal) equations.
Name Type Default Description
ellipsoid Ellipsoid Ellipsoid.WGS84 optional The ellipsoid.
See:

Members

staticCesium.WebMercatorProjection.MaximumLatitude : Number

The maximum latitude (both North and South) supported by a Web Mercator (EPSG:3857) projection. Technically, the Mercator projection is defined for any latitude up to (but not including) 90 degrees, but it makes sense to cut it off sooner because it grows exponentially with increasing latitude. The logic behind this particular cutoff value, which is the one used by Google Maps, Bing Maps, and Esri, is that it makes the projection square. That is, the rectangle is equal in the X and Y directions. The constant value is computed by calling: WebMercatorProjection.mercatorAngleToGeodeticLatitude(Math.PI)

readonlyellipsoid : Ellipsoid

Gets the Ellipsoid.

Methods

staticCesium.WebMercatorProjection.geodeticLatitudeToMercatorAngle(latitude) → Number

Converts a geodetic latitude in radians, in the range -PI/2 to PI/2, to a Mercator angle in the range -PI to PI.
Name Type Description
latitude Number The geodetic latitude in radians.
Returns:
The Mercator angle.

staticCesium.WebMercatorProjection.mercatorAngleToGeodeticLatitude(mercatorAngle) → Number

Converts a Mercator angle, in the range -PI to PI, to a geodetic latitude in the range -PI/2 to PI/2.
Name Type Description
mercatorAngle Number The angle to convert.
Returns:
The geodetic latitude in radians.

project(cartographic, result) → Cartesian3

Converts geodetic ellipsoid coordinates, in radians, to the equivalent Web Mercator X, Y, Z coordinates expressed in meters and returned in a Cartesian3. The height is copied unmodified to the Z coordinate.
Name Type Description
cartographic Cartographic The cartographic coordinates in radians.
result Cartesian3 optional The instance to which to copy the result, or undefined if a new instance should be created.
Returns:
The equivalent web mercator X, Y, Z coordinates, in meters.

unproject(cartesian, result) → Cartographic

Converts Web Mercator X, Y coordinates, expressed in meters, to a Cartographic containing geodetic ellipsoid coordinates. The Z coordinate is copied unmodified to the height.
Name Type Description
cartesian Cartesian3 The web mercator Cartesian position to unrproject with height (z) in meters.
result Cartographic optional The instance to which to copy the result, or undefined if a new instance should be created.
Returns:
The equivalent cartographic coordinates.