If only one parameter is provided, the ellipsoid is assumed to be a sphere. The following example defines a sphere with a radius of 6 000 kilometers (6000000 meters).

IlvEllipsoid ellipsoid = new IlvEllipsoid(6000000D);

Most of the mapping applications use the ellipsoid IlvEllipsoid.SPHERE that defines a sphere having dimensions very close to those of the Earth. Generally, the selected ellipsoid should be as close as possible to the actual shape of the Earth as far as the region to be represented is concerned. The radius of the sphere is expressed in meters.

The following example defines an ellipsoid with an equatorial radius of 6000 kilometers and an eccentricity squared of 0.0067:

IlvEllipsoid ellipsoid = new IlvEllipsoid(6000000D,0.0067D);

The following example defines an ellipsoid with an equatorial radius of 6000 kilometers and a polar radius of 5900 kilometers:

IlvEllipsoid ellipsoid = new IlvEllipsoid(6000000D,
                      IlvEllipsoid.ESFromPolarRadius(6000000D, 5900000D));

The polar radius is converted to an eccentricity squared value with the ESFromPolarRadius() method.

The class IlvEllipsoid provides the following conversion methods for polar radius and flattening: