new 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
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staticWebMercatorProjection.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)
-
ellipsoid :Ellipsoid
-
Gets the
Ellipsoid.
Methods
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staticWebMercatorProjection.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 latitudeNumber The geodetic latitude in radians. Returns:
The Mercator angle. -
staticWebMercatorProjection.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 mercatorAngleNumber 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 cartographicCartographic The cartographic coordinates in radians. resultCartesian3 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
Cartographiccontaining geodetic ellipsoid coordinates. The Z coordinate is copied unmodified to the height.Name Type Description cartesianCartesian3 The web mercator Cartesian position to unrproject with height (z) in meters. resultCartographic optional The instance to which to copy the result, or undefined if a new instance should be created. Returns:
The equivalent cartographic coordinates.