org.apache.sis.storage.gdal

Class Proj4Factory

Object

AbstractFactory

GeodeticAuthorityFactory

Proj4Factory

All Implemented Interfaces:

AuthorityFactory, CRSAuthorityFactory, Factory

public class Proj4Factory
extends GeodeticAuthorityFactory
implements CRSAuthorityFactory

A factory for Coordinate Reference Systems created from Proj.4 definitions. This authority factory recognizes codes in the "Proj4" name space. The main methods in this class are:

• get­Authority()
• create­Coordinate­Reference­System(String)
• create­Operation(Coordinate­Reference­System, Coordinate­Reference­System, boolean)
• create­Parameterized­Transform(Parameter­Value­Group)

Other methods delegate to one of above-cited methods if possible, or throw a Factory­Exception otherwise.

Since:

0.8

Defined in the sis-gdal module

Constructor Summary

Constructors

Constructor and Description
Proj4Factory() Creates a default factory.
Proj4Factory(Map<String,?> properties) Creates a new Proj.4 factory.

Method Summary

Modifier and Type	Method and Description
CoordinateReferenceSystem	createCoordinateReferenceSystem(String code) Creates a new CRS from the given Proj.4 definition.
IdentifiedObject	createObject(String code) Creates a new geodetic object from the given Proj.4 definition.
CoordinateOperation	createOperation(CoordinateReferenceSystem sourceCRS, CoordinateReferenceSystem targetCRS, boolean force) Creates an operation for conversion or transformation between two coordinate reference systems.
MathTransform	createParameterizedTransform(ParameterValueGroup parameters) Creates a transform from a group of parameters.
Citation	getAuthority() Returns the project that defines the codes recognized by this factory.
Set<String>	getAuthorityCodes(Class<? extends IdentifiedObject> type) Returns the set of authority codes for objects of the given type.
Set<OperationMethod>	getAvailableMethods(Class<? extends SingleOperation> type) Returns some map projection methods supported by Proj.4.
Set<String>	getCodeSpaces() Returns the code space of the authority.
ParameterValueGroup	getDefaultParameters(String method) Returns the default parameter values for a math transform using the given operation method.
OperationMethod	getOperationMethod(String name) Returns the operation method of the given name.

Methods inherited from class GeodeticAuthorityFactory

create­Cartesian­CS, create­Compound­CRS, create­Coordinate­Operation, create­Coordinate­System, create­Coordinate­System­Axis, create­Cylindrical­CS, create­Datum, create­Derived­CRS, create­Ellipsoid, create­Ellipsoidal­CS, create­Engineering­CRS, create­Engineering­Datum, create­Extent, create­From­Coordinate­Reference­System­Codes, create­Geocentric­CRS, create­Geodetic­Datum, create­Geographic­CRS, create­Image­CRS, create­Image­Datum, create­Operation­Method, create­Parameter­Descriptor, create­Parametric­CRS, create­Parametric­CS, create­Parametric­Datum, create­Polar­CS, create­Prime­Meridian, create­Projected­CRS, create­Spherical­CS, create­Temporal­CRS, create­Temporal­Datum, create­Time­CS, create­Unit, create­Vertical­CRS, create­Vertical­CS, create­Vertical­Datum, get­Description­Text, new­Identified­Object­Finder, to­String, trim­Namespace

Methods inherited from class AbstractFactory

get­Vendor

Methods inherited from class Object

clone, equals, finalize, get­Class, hash­Code, notify, notify­All, wait, wait, wait

Methods inherited from interface CRSAuthorityFactory

create­Compound­CRS, create­Derived­CRS, create­Engineering­CRS, create­Geocentric­CRS, create­Geographic­CRS, create­Image­CRS, create­Projected­CRS, create­Temporal­CRS, create­Vertical­CRS

Methods inherited from interface AuthorityFactory

get­Description­Text

Methods inherited from interface Factory

get­Vendor

Constructor Detail

Proj4Factory

public Proj4Factory()

Creates a default factory.

Proj4Factory

public Proj4Factory(Map<String,?> properties)

Creates a new Proj.4 factory. The properties argument is an optional map for specifying common properties shared by the objects to create. Some available properties are listed there. Unknown properties, or properties that do not apply, or properties for which Proj4Factory supplies itself a value, are ignored.

Parameters:

properties - common properties for the objects to create, or null if none.

Method Detail

getAuthority

public Citation getAuthority()

Returns the project that defines the codes recognized by this factory. The authority determines the code space.

Specified by:

get­Authority in interface Authority­Factory

Specified by:

get­Authority in class Geodetic­Authority­Factory

Returns:

Citations.PROJ4.

See Also:

Abstract­Factory.get­Vendor()

getCodeSpaces

public Set<String> getCodeSpaces()

Returns the code space of the authority. The code space is the prefix that may appear before codes. It allows to differentiate Proj.4 definitions from EPSG codes or other authorities. The code space is removed by create­Coordinate­Reference­System(String) before the definition string is passed to Proj.4

Example a complete identifier can be "Proj4:+init=epsg:4326". Note that this is not equivalent to the standard "EPSG:4326" definition since the axis order is not the same. The "Proj4:" prefix specifies that the remaining part of the string is a Proj.4 definition; the presence of an "epsg" word in the definition does not change that fact.

Overrides:

get­Code­Spaces in class Geodetic­Authority­Factory

Returns:

"Proj4".

getAuthorityCodes

public Set<String> getAuthorityCodes(Class<? extends IdentifiedObject> type)
                              throws FactoryException

Returns the set of authority codes for objects of the given type. Current implementation can not return complete Proj.4 definition strings. Instead, this method currently returns only fragments (e.g. "+proj=lcc").

Specified by:

get­Authority­Codes in interface Authority­Factory

Parameters:

type - the spatial reference objects type.

Returns:

fragments of definition strings for spatial reference objects of the given type.

Throws:

Factory­Exception - if access to the underlying database failed.

getAvailableMethods

public Set<OperationMethod> getAvailableMethods(Class<? extends SingleOperation> type)

Returns some map projection methods supported by Proj.4. Current implementation can not return the complete list of Proj.4 method, but returns the main ones. For each operation method in the returned set, the Proj.4 projection name can be obtained as below:

String proj = IdentifiedObjects.getName(method, Citations.PROJ4);

The proj names obtained as above can be given in argument to the get­Operation­Method(String) and get­Default­Parameters(String) methods.

Parameters:

type - Single­Operation.class for fetching all operation methods, or Projection.class for fetching only map projection methods.

Returns:

methods available in this factory for coordinate operations of the given type.

See Also:

Default­Math­Transform­Factory.get­Available­Methods(Class)

getOperationMethod

public OperationMethod getOperationMethod(String name)
                                   throws FactoryException

Returns the operation method of the given name. The given argument can be a Proj.4 projection name, but other authorities (OGC, EPSG…) are also accepted. A partial list of supported projection names can be obtained by get­Available­Methods(Class). Some examples of Proj.4 projection names are given below (not all of them are supported by this Proj.4 wrapper).

Some Proj.4 projection names

Name	Meaning
aea	Albers Equal-Area Conic
aeqd	Azimuthal Equidistant
cass	Cassini-Soldner
cea	Cylindrical Equal Area
eck4	Eckert IV
eck6	Eckert VI
eqdc	Equidistant Conic
gall	Gall Stereograpic
geos	Geostationary Satellite View
gnom	Gnomonic
krovak	Krovak Oblique Conic Conformal
laea	Lambert Azimuthal Equal Area
lcc	Lambert Conic Conformal
merc	Mercator
mill	Miller Cylindrical
moll	Mollweide
nzmg	New Zealand Map Grid
omerc	Oblique Mercator
ortho	Orthographic
sterea	Oblique Stereographic
stere	Stereographic
robin	Robinson
sinu	Sinusoidal
tmerc	Transverse Mercator
vandg	VanDerGrinten

The default implementation delegates to a Default­Coordinate­Operation­Factory instance. It works because the Apache SIS operation methods declare the Proj.4 projection names as aliases.

Parameters:

name - the name of the operation method to fetch.

Returns:

the operation method of the given name.

Throws:

Factory­Exception - if the requested operation method can not be fetched.

See Also:

Default­Coordinate­Operation­Factory.get­Operation­Method(String)

getDefaultParameters

public ParameterValueGroup getDefaultParameters(String method)
                                         throws NoSuchIdentifierException

Returns the default parameter values for a math transform using the given operation method. The given argument can be a Proj.4 projection name, but other authorities (OGC, EPSG…) are also accepted. A partial list of supported projection names can be obtained by get­Available­Methods(Class). The returned parameters can be given to create­Parameterized­Transform(Parameter­Value­Group).

Parameters:

method - the case insensitive name of the coordinate operation method to search for.

Returns:

a new group of parameter values for the Operation­Method identified by the given name.

Throws:

No­Such­Identifier­Exception - if there is no method registered for the given name or identifier.

createParameterizedTransform

public MathTransform createParameterizedTransform(ParameterValueGroup parameters)
                                           throws FactoryException

Creates a transform from a group of parameters. The Operation­Method name is inferred from the parameter group name. Each parameter value is formatted as a Proj.4 parameter in a definition string.

Example:

ParameterValueGroup p = factory.getDefaultParameters("Mercator");
p.parameter("semi_major").setValue(6378137.000);
p.parameter("semi_minor").setValue(6356752.314);
MathTransform mt = factory.createParameterizedTransform(p);

The corresponding Proj.4 definition string is:

+proj=merc +a=6378137.0 +b=6356752.314

Parameters:

parameters - the parameter values.

Returns:

the parameterized transform.

Throws:

Factory­Exception - if the object creation failed. This exception is thrown if some required parameter has not been supplied, or has illegal value.

See Also:

get­Default­Parameters(String), get­Available­Methods(Class)

createObject

public IdentifiedObject createObject(String code)
                              throws FactoryException

Creates a new geodetic object from the given Proj.4 definition. The default implementation delegates to create­Coordinate­Reference­System(String).

Specified by:

create­Object in interface Authority­Factory

Specified by:

create­Object in class Geodetic­Authority­Factory

Parameters:

code - the Proj.4 definition of the geodetic object to create.

Returns:

a geodetic created from the given definition.

Throws:

Factory­Exception - if the geodetic object can not be created for the given definition.

See Also:

Abstract­Identified­Object

createCoordinateReferenceSystem

public CoordinateReferenceSystem createCoordinateReferenceSystem(String code)
                                                          throws FactoryException

Creates a new CRS from the given Proj.4 definition. The "Proj4:" prefix (ignoring case), if present, is ignored.

Apache SIS extension

Proj.4 unconditionally requires 3 letters for the "+axis=" parameter — for example "neu" for North, East and Up respectively — regardless the number of dimensions in the CRS to create. Apache SIS makes the vertical direction optional:

• If the vertical direction is present (as in "neu"), a three-dimensional CRS is created.
• If the vertical direction is absent (as in "ne"), a two-dimensional CRS is created.

Examples:

• "+init=epsg:4326" (not equivalent to the standard EPSG::4326 definition)
• "+proj=latlong +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0" (default to two-dimensional CRS)
• "+proj=latlon +a=6378137.0 +b=6356752.314245179 +pm=0.0 +axis=ne" (explicitely two-dimensional)
• "+proj=latlon +a=6378137.0 +b=6356752.314245179 +pm=0.0 +axis=neu" (three-dimensional)

Specified by:

create­Coordinate­Reference­System in interface CRSAuthority­Factory

Overrides:

create­Coordinate­Reference­System in class Geodetic­Authority­Factory

Parameters:

code - the Proj.4 definition of the CRS object to create.

Returns:

a CRS created from the given definition.

Throws:

Factory­Exception - if the CRS object can not be created for the given definition.

See Also:

Proj4.create­CRS(String, int)

createOperation

public CoordinateOperation createOperation(CoordinateReferenceSystem sourceCRS,
                                           CoordinateReferenceSystem targetCRS,
                                           boolean force)
                                    throws FactoryException

Creates an operation for conversion or transformation between two coordinate reference systems. The given CRSs should be instances created by this factory. If not, then there is a choice:

• If force is false, then this method returns null.
• Otherwise this method always uses Proj.4 for performing the coordinate operations, regardless if the given CRS were created from Proj.4 definition strings or not. This method fails if it can not map the given CRS to Proj.4 data structures.

Parameters:

source­CRS - the source coordinate reference system.

target­CRS - the target coordinate reference system.

force - whether to force the creation of a Proj.4 transform even if the given CRS are not wrappers around Proj.4 data structures.

Returns:

a coordinate operation for transforming coordinates from the given source CRS to the given target CRS, or null if the given CRS are not wrappers around Proj.4 data structures and force is false.

Throws:

Factory­Exception - if force is true and this method can not create Proj.4 transform for the given pair of coordinate reference systems.

See Also:

Proj4.create­Operation(Coordinate­Reference­System, Coordinate­Reference­System, boolean), Default­Coordinate­Operation­Factory.create­Operation(Coordinate­Reference­System, Coordinate­Reference­System)