org.osgeo.proj4j.CRSFactory Maven / Gradle / Ivy
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package org.osgeo.proj4j;
import org.osgeo.proj4j.io.Proj4FileReader;
import org.osgeo.proj4j.parser.Proj4Parser;
/**
* A factory which can create {@link CoordinateReferenceSystem}s
* from a variety of ways
* of specifying them.
* This is the primary way of creating coordinate systems
* for carrying out projections transformations.
*
* CoordinateReferenceSystems can be used to
* define {@link CoordinateTransform}s to perform transformations
* on {@link ProjCoordinate}s.
*
* @author Martin Davis
*
*/
public class CRSFactory
{
private static Proj4FileReader csReader = new Proj4FileReader();
private static Registry registry = new Registry();
// TODO: add method to allow reading from arbitrary PROJ4 CS file
/**
* Creates a new factory.
*/
public CRSFactory()
{
}
/**
* Gets the {@link Registry} used by this factory.
* @return the Registry
*/
public Registry getRegistry()
{
return registry;
}
/**
* Creates a {@link CoordinateReferenceSystem} (CRS) from a well-known name.
* CRS names are of the form: "authority:code",
* with the components being:
*
* - authority is a code for a namespace supported by
* PROJ.4.
* Currently supported values are
* EPSG,
* ESRI,
* WORLD,
* NA83,
* NAD27.
* If no authority is provided, the EPSG namespace is assumed.
*
- code is the id of a coordinate system in the authority namespace.
* For example, in the EPSG namespace a code is an integer value
* which identifies a CRS definition in the EPSG database.
* (Codes are read and handled as strings).
*
* An example of a valid CRS name is EPSG:3005.
*
* @param name the name of a coordinate system, with optional authority prefix
* @return the {@link CoordinateReferenceSystem} corresponding to the given name
* @throws UnsupportedParameterException if a PROJ.4 parameter is not supported
* @throws InvalidValueException if a parameter value is invalid
* @throws UnknownAuthorityCodeException if the authority code cannot be found
*/
public CoordinateReferenceSystem createFromName(String name)
throws UnsupportedParameterException, InvalidValueException, UnknownAuthorityCodeException
{
String[] params = csReader.getParameters(name);
if (params == null)
throw new UnknownAuthorityCodeException(name);
return createFromParameters(name, params);
}
/**
* Creates a {@link CoordinateReferenceSystem}
* from a PROJ.4 projection parameter string.
*
* An example of a valid PROJ.4 projection parameter string is:
*
* +proj=aea +lat_1=50 +lat_2=58.5 +lat_0=45 +lon_0=-126 +x_0=1000000 +y_0=0 +ellps=GRS80 +units=m
*
* @param name a name for this coordinate system (may be null for an anonymous coordinate system)
* @param paramStr a PROJ.4 projection parameter string
* @return the specified {@link CoordinateReferenceSystem}
* @throws UnsupportedParameterException if a given PROJ.4 parameter is not supported
* @throws InvalidValueException if a supplied parameter value is invalid
*/
public CoordinateReferenceSystem createFromParameters(String name, String paramStr)
throws UnsupportedParameterException, InvalidValueException
{
return createFromParameters(name, splitParameters(paramStr));
}
/**
* Creates a {@link CoordinateReferenceSystem}
* defined by an array of PROJ.4 projection parameters.
* PROJ.4 parameters are generally of the form
* "+name=value".
*
* @param name a name for this coordinate system (may be null)
* @param params an array of PROJ.4 projection parameters
* @return a {@link CoordinateReferenceSystem}
* @throws UnsupportedParameterException if a PROJ.4 parameter is not supported
* @throws InvalidValueException if a parameter value is invalid
*/
public CoordinateReferenceSystem createFromParameters(String name, String[] params)
throws UnsupportedParameterException, InvalidValueException
{
if (params == null)
return null;
Proj4Parser parser = new Proj4Parser(registry);
return parser.parse(name, params);
}
private static String[] splitParameters(String paramStr)
{
String[] params = paramStr.split("\\s+");
return params;
}
}