Because of this and because of the fact, the earth isn't a perfect sphere --or even a perfect ellipsoid for that matter--, there is no 'best' projection for the projection of every region on earth. Hence a lot of different mathematical projectional functions have been developed over the years. It is possible to categorize these functions into three groups:
You can achieve this loading by supplying the class
attribute to a crs:projectedCRS/crs:projection
element in the 'deegree-crs-configuration.xml'. This attribute must contain the full class name (with package), e.g.
<crs:projection class='my.package.and.projection.Implementation'>
public MyProjection(
{@link org.deegree.crs.coordinatesystems.GeographicCRS} underlyingCRS,
double falseNorthing,
double falseEasting,
javax.vecmath.Point2d naturalOrigin,
{@link org.deegree.crs.components.Unit} units,
double scale,
java.util.List<org.w3c.dom.Element> yourProjectionElements
);
The first six parameters are common to all projections (for an explanation of their meaning take a look at {@link org.deegree.crs.projections.Projection}). The last list, will contain all xml-dom elements you supplied in the deegree configuration (child elements of the crs:projection/crs:MyProjection), thus relieving you of the parsing of the deegree-crs-configuration.xml document.