Package org.deegree.crs.configuration

The org.deegree.crs.configuraton package contains the classes necessary to read crs-definitions from a specified backend ( database or xml-file).

See:
Description

Interface Summary

CRSProvider

The CRSProvider will allow the support for different crs-definitions formats within the crs package.

Class Summary

AbstractCRSProvider<T>	add class documentation here.
CRSConfiguration	The CRSConfiguration creates, instantiates and supplies a configured CRS-Provider.
TransformationFactory	The TransformationFactory class is the central access point for all transformations between different crs's.

Enum Summary

AbstractCRSProvider.SupportedProjectionParameters	The SupportedProjectionParameters enumeration defines currently supported projection parameters
AbstractCRSProvider.SupportedProjections	The SupportedProjections enumeration defines currently supported projections
AbstractCRSProvider.SupportedTransformationParameters	The SupportedTransformationParameters enumeration defines currently supported transformation parameters
AbstractCRSProvider.SupportedTransformations	The SupportedTransformations enumeration defines currently supported transformations

Package org.deegree.crs.configuration Description

The org.deegree.crs.configuraton package contains the classes necessary to read crs-definitions from a specified backend ( database or xml-file).

For this purpose the CRSProvider interface is created. It allows the CRSConfiguration to rely on a wide variety of different 'crs-definitions-formats' for example deegree-crs, wkt (not implemented yet), proj4 or gml (not implementedj yet). The good thing is, the interface defines an export method, which can be called with a crs to receive a crs-definitions for the implementing interface, thus allowing to create an arbitrary configuration swift between the implementations.

The default crs configuration can be changed by editing the org.deegree.crs.configuration.crs_providers.properties file, the default provider is org.deegree.crs.configuration.deegree.DatabaseCRSProvider.

Automatic loading of projection/transformation classes

It is possible to create your own projection/transformation classes, which the default provider will load automatically.

You can achieve this loading by supplying the class attribute to a crs:projectedCRS/crs:projection or crs:coordinateSystem/crs:transformation 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'>

Because the loading is done with reflections your classes must sustain following criteria:

Projections

1. It must be a sub class of Projection
2. A constructor with following signature must be supplied:
   public MyProjection(
    GeographicCRS underlyingCRS,
    double falseNorthing,
    double falseEasting,
    javax.vecmath.Point2d naturalOrigin,
    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 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.

Transformations

1. It must be a sub class of PolynomialTransformation
2. A constructor with following signature must be supplied:
   public MyTransformation(
    java.util.list<Double> aValues,
    java.util.list<Double> bValues,
    CoordinateSystem targetCRS,
    java.util.List<org.w3c.dom.Element> yourTransformationElements
);


   The first three parameters are common to all polynomial values (for an explanation of their meaning take a look at PolynomialTransformation). Again, the last list, will contain all xml-dom elements you supplied in the deegree configuration (child elements of the crs:transformation/crs:MyTransformation), thus relieving you of the parsing of the deegree-crs-configuration.xml document.

Author:

Rutger Bezema, last edited by: $Author: rbezema $ @version $Revision: 17229 $, $Date: 2007-03-20 10:15:15 +0100 (Di, 20 Mrz 2007)$