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308 lines
13 KiB
Plaintext
308 lines
13 KiB
Plaintext
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/*!
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* \class QgsCoordinateReferenceSystem
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* \brief Class for storing a spatial reference system (CRS)
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*/
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class QgsCoordinateReferenceSystem
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{
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%TypeHeaderCode
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#include <qgscoordinatereferencesystem.h>
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%End
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public:
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// typedef void (*CUSTOM_CRS_VALIDATION)(QgsCoordinateReferenceSystem*);
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enum CrsType
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{
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InternalCrsId,
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PostgisCrsId,
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EpsgCrsId
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};
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//! Default constructor
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QgsCoordinateReferenceSystem();
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~QgsCoordinateReferenceSystem();
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/*!
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* Constructs a CRS object from a string definition as defined in the createFromString
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* member function (by default a WKT definition).
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* @param theDefinition A String containing a coordinate reference system definition.
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*/
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explicit QgsCoordinateReferenceSystem( QString theDefinition );
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/*! Use this constructor when you want to create a CRS object using
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* a postgis SRID, an EpsgCrsId id or a QGIS CRS_ID.
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* @note We encourage you to use EpsgCrsId, Wkt or Proj4 to describe CRS's in your code
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* wherever possible. QGSI CRS_IDs are not guaranteed to be permanent / involatile.
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* @param theId The ID no valid for the chosen coordinate system id type
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* @param theType One of the types described in QgsCoordinateReferenceSystem::CrsType
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*/
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QgsCoordinateReferenceSystem( const long theId, CrsType theType = PostgisCrsId );
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// Misc helper functions -----------------------
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bool createFromId( const long theId, CrsType theType = PostgisCrsId );
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/**
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* \brief Set up this CRS from the given OGC CRS
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*
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* Sets this CRS to the given OGC WMS-format Coordinate Reference Systems.
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*
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* \retval false if not given an valid label
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*/
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bool createFromOgcWmsCrs( QString theCrs );
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/*! Set up this srs by fetching the appropriate information from the
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* sqlite backend. First the system level read only srs.db will be checked
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* and then the users ~/.qgis/qgis.db database will be checked for a match.
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* @note Any members will be overwritten during this process.
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* @param theSrid The postgis SRID for the desired spatial reference system.
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*/
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bool createFromSrid( const long theSrid );
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/*! Set up this srs using a Wkt spatial ref sys definition.
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* The wkt will be converted to a proj4 string using OGR helper
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* functions. After this the srs databasses will be searched for matches.
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* First the system level read only srs.db will be checked
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* and then the users ~/.qgis/qgis.db database will be checked for a match.
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* @note Any members will be overwritten during this process.
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* @note SRID and EpsgCrsId may be blank if no match can be found on srs db.
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* @param theWkt The Wkt for the desired spatial reference system.
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* @return bool TRUE if success else false
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*/
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bool createFromWkt( const QString theWkt );
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/*! Set up this srs by fetching the appropriate information from the
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* sqlite backend. If the srsid is < 100000, only the system srs.db
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* will be checked. If the srsid > 100000 the srs will be retrieved from
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* the ~/.qgis/qgis.db
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* @note Any members will be overwritten during this process.
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* @param theSrsId The QGIS SrsId for the desired spatial reference system.
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* @return bool TRUE if success else false
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*/
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bool createFromSrsId( const long theSrsId );
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/*! Set up this srs by passing it a proj4 style formatted string.
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* The string will be parsed and the projection and ellipsoid
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* members set and the remainder of the proj4 string will be stored
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* in the parameters member. The reason for this is so that we
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* can easily present the user with 'natural language' representation
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* of the projection and ellipsoid by looking them up in the srs.bs sqlite
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* database. Also having the ellpse and proj elements stripped out
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* is helpful to speed up globbing queries (see below).
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*
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* We try to match the proj string to and srsid using the following logic:
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*
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* - perform a whole text search on srs name (if not null). The srs name will
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* have been set if this method has been delegated to from createFromWkt.
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* - if the above does not match perform a whole text search on proj4 string (if not null)
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* - if none of the above match convert the proj4 string to an OGR CRS
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* then check if its a geocs or a proj cs (using ogr isGeographic)
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* then sequentially walk through the database (first users qgis.db srs tbl then
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* system srs.db tbl), converting each entry into an ogr srs and using isSame
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* or isSameGeocs (essentially calling the == overloaded operator). We'll try to
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* be smart about this and first parse out the proj and ellpse strings and only
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* check for a match in entities that have the same ellps and proj entries so
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* that it doesn't munch yer cpu so much.
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*
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* @note If the srs was not matched, we will create a new entry on the users tbl_srs
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* for this srs.
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*
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* @param theProjString A proj4 format string
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* @return bool TRUE if success else false
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*/
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bool createFromProj4( const QString theProjString );
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/*! Set up this srs from a string definition, by default a WKT definition. Otherwise
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* the string defines a authority, followed by a colon, followed by the definition.
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* The authority can be one of "epsg", "postgis", "internal" for integer definitions,
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* and "wkt" or "proj4" for string definitions. The implementation of each authority
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* uses the corresponding createFrom... function.
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* @param theDefinition A String containing a coordinate reference system definition.
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*/
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bool createFromString( const QString theDefinition );
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/*! Set up this srs from a various text formats.
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*
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* Valid formats: WKT string, "EPSG:n", "EPSGA:n", "AUTO:proj_id,unit_id,lon0,lat0",
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* "urn:ogc:def:crs:EPSG::n", PROJ.4 string, filename (with WKT, XML or PROJ.4 string),
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* well known name (such as NAD27, NAD83, WGS84 or WGS72),
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* ESRI::[WKT string] (directly or in a file), "IGNF:xxx"
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*
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* For more details on supported formats see OGRSpatialReference::SetFromUserInput()
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* ( http://www.gdal.org/ogr/classOGRSpatialReference.html#aec3c6a49533fe457ddc763d699ff8796 )
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* @note this function generates a WKT string using OSRSetFromUserInput() and
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* passes it to createFromWkt() function.
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* @param theDefinition A String containing a coordinate reference system definition.
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*
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* @note added in 1.8
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*/
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bool createFromUserInput( const QString theDefinition );
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/*! Make sure that ESRI WKT import is done properly.
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* This is required for proper shapefile CRS import when using gdal>= 1.9.
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* @note This function is called by createFromUserInput() and QgsOgrProvider::crs(), there is usually
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* no need to call it from elsewhere.
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* @note This function sets CPL config option GDAL_FIX_ESRI_WKT to a proper value,
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* unless it has been set by the user through the commandline or an environment variable.
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* For more details refer to OGRSpatialReference::morphFromESRI() .
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*
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* @note added in 1.8
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*/
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static void setupESRIWktFix();
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/*! Find out whether this CRS is correctly initialised and usable */
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bool isValid() const;
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/*! Perform some validation on this CRS. If the sts doesn't validate the
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* default behaviour settings for layers with unknown CRS will be
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* consulted and acted on accordingly. By hell or high water this
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* method will do its best to make sure that this CRS is valid - even
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* if that involves resorting to a hard coded default of geocs:wgs84.
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*
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* @note It is not usually necessary to use this function, unless you
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* are trying to force this srs to be valid.
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*/
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void validate();
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/*! This is a globbing function to try to find a record in the database
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* that matches a CRS defined only by a proj4string. The goal is to
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* learn what the tbl_srs.srs_id value is for the CRS. Internally
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* the source CRS is converted to an OGR srs object using the proj4string call
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* and then every record in the database that matches projection and ellipsoid
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* will be converted to an OGR srs in turn and compared to the source CRS.
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* There are some gotchas with using ogr isSame() srs comparison, but
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* its more effective than using straight string comparison of proj4params.
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* @note The ellipsoid and projection acronyms must be set as well as the proj4string!
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* @return long the SrsId of the matched CRS
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*/
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long findMatchingProj();
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/*! Overloaded == operator used to compare to CRS's.
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* Internally it will delegate to the equals method described below
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*/
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bool operator==( const QgsCoordinateReferenceSystem &theSrs ) const;
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/*! Overloaded != operator used to compare to CRS's.
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* Returns opposite bool value to operator ==
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*/
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bool operator!=( const QgsCoordinateReferenceSystem &theSrs ) const;
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/*! Restores state from the given Dom node.
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* @param theNode The node from which state will be restored
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* @return bool True on success, False on failure
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*/
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bool readXML( QDomNode & theNode );
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/*! Stores state to the given Dom node in the given document.
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* Below is an example of the generated tag.
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\verbatim
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<spatialrefsys>
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<proj4>+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs </proj4>
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<srsid>2585</srsid>
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<srid>4326</srid>
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<epsg>4326</epsg>
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<description>WGS 84</description>
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<projectionacronym>longlat</projectionacronym>
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<ellipsoidacronym>WGS84</ellipsoidacronym>
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</spatialrefsys>
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\endverbatim
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* @param theNode The node in which state will be restored
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* @param theDoc The document in which state will be stored
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* @return bool True on success, False on failure
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*/
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bool writeXML( QDomNode & theNode, QDomDocument & theDoc ) const;
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/** Sets custom function to force valid CRS
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* QGIS uses implementation in QgisGui::customSrsValidation
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*/
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// static void setCustomSrsValidation( CUSTOM_CRS_VALIDATION f );
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/** Gets custom function
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* @note not available in python bindings
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*/
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// static CUSTOM_CRS_VALIDATION customSrsValidation();
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// Accessors -----------------------------------
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/*! Get the SrsId - if possible
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* @return long theSrsId The internal sqlite3 srs.db primary key for this srs
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*/
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long srsid() const;
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/*! Get the postgis srid for this srs
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* @return long theSRID the Postgis spatial_ref_sys identifier for this srs (defaults to 0)
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*/
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long postgisSrid() const;
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/*! Get the authority identifier for this srs
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* @return QString the Authority identifier for this srs
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* @note added in 1.5
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*/
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QString authid() const;
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/*! Get the Description
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* @return QString the Description A textual description of the srs.
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* @note A zero length string will be returned if the description is uninitialised
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*/
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QString description() const;
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/*! Get the Projection Acronym
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* @return QString theProjectionAcronym The official proj4 acronym for the projection family
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* @note A zero length string will be returned if the projectionAcronym is uninitialised
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*/
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QString projectionAcronym() const;
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/*! Get the Ellipsoid Acronym
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* @return QString theEllipsoidAcronym The official proj4 acronym for the ellipoid
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* @note A zero length string will be returned if the ellipsoidAcronym is uninitialised
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*/
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QString ellipsoidAcronym() const;
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/*! A helper to get an wkt representation of this srs
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* @return string containing Wkt of the srs
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*/
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QString toWkt() const;
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/** Get the Proj Proj4 string representation of this srs.
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* If proj and ellps keys are found in the parameters,
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* they will be stripped out and the Projection and ellipsoid acronyms will be
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* overridden with these.
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* @return QString theProj4String Proj4 format specifies that define this srs.
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* @note A zero length string will be returned if the toProj4 is uninitialised
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*/
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QString toProj4() const;
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/*! Get this Geographic? flag
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* @return bool theGeoFlag Whether this is a geographic or projected coordinate system
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*/
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bool geographicFlag() const;
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/*! return if axis is inverted (eg. for WMS 1.3)
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* @return bool Whether this is crs axis is inverted
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* @note added in 1.8
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*/
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bool axisInverted() const;
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/*! Get the units that the projection is in
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* @return QGis::UnitType that gives the units for the coordinate system
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*/
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QGis::UnitType mapUnits() const;
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// Mutators -----------------------------------
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/*! Set user hint for validation
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*/
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void setValidationHint( QString html );
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/*! Get user hint for validation
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*/
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QString validationHint();
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/*! Update proj.4 parameters in our database from proj.4
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* @returns number of updated CRS on success and
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* negative number of failed updates in case of errors.
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* @note added in 1.8
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*/
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static int syncDb();
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};
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