Create a SphMercProjection.
Return the projection's ID.
The value "epsg:3857".
Project a longitude and latitude into Spherical Mercator.
the longitude.
the latitude.
Two-member array containing easting and northing.
Unproject a Spherical Mercator easting and northing.
Two-member array containing easting and northing
Two-member array containing longitude and latitude
Projection interface, you can create your own custom projection by implementing project() and unproject().