Spatial Reference System C++ API

Coordinate systems services.

Defines

USGS_ANGLE_DECIMALDEGREES

Angle is in decimal degrees.

USGS_ANGLE_PACKEDDMS

Angle is in packed degree minute second.

USGS_ANGLE_RADIANS

Angle is in radians.

Functions

OGRCoordinateTransformation *OGRCreateCoordinateTransformation(const OGRSpatialReference *poSource, const OGRSpatialReference *poTarget)

Create transformation object.

This is the same as the C function OCTNewCoordinateTransformation().

Input spatial reference system objects are assigned by copy (calling clone() method) and no ownership transfer occurs.

The delete operator, or OCTDestroyCoordinateTransformation() should be used to destroy transformation objects.

This will honour the axis order advertized by the source and target SRS, as well as their “data axis to SRS axis mapping”. To have a behaviour similar to GDAL < 3.0, the OGR_CT_FORCE_TRADITIONAL_GIS_ORDER configuration option can be set to YES.

Return

NULL on failure or a ready to use transformation object.

Parameters
  • poSource: source spatial reference system.

  • poTarget: target spatial reference system.

OGRCoordinateTransformation *OGRCreateCoordinateTransformation(const OGRSpatialReference *poSource, const OGRSpatialReference *poTarget, const OGRCoordinateTransformationOptions &options)

Create transformation object.

This is the same as the C function OCTNewCoordinateTransformationEx().

Input spatial reference system objects are assigned by copy (calling clone() method) and no ownership transfer occurs.

The delete operator, or OCTDestroyCoordinateTransformation() should be used to destroy transformation objects.

This will honour the axis order advertized by the source and target SRS, as well as their “data axis to SRS axis mapping”. To have a behaviour similar to GDAL < 3.0, the OGR_CT_FORCE_TRADITIONAL_GIS_ORDER configuration option can be set to YES.

The source SRS and target SRS should generally not be NULL. This is only allowed if a custom coordinate operation is set through the hOptions argument.

If options contains a user defined coordinate transformation pipeline, it will be unconditionally used. If options has an area of interest defined, it will be used to research the best fitting coordinate transformation (which will be used for all coordinate transformations, even if they don’t fall into the declared area of interest) If no options are set, then a list of candidate coordinate operations will be reseached, and at each call to Transform(), the best of those candidate regarding the centroid of the coordinate set will be dynamically selected.

Return

NULL on failure or a ready to use transformation object.

Since

GDAL 3.0

Parameters
  • poSource: source spatial reference system.

  • poTarget: target spatial reference system.

  • options: Coordinate transformation options.

class OGR_SRSNode
#include <ogr_spatialref.h>

Objects of this class are used to represent value nodes in the parsed representation of the WKT SRS format.

For instance UNIT[“METER”,1] would be rendered into three OGR_SRSNodes. The root node would have a value of UNIT, and two children, the first with a value of METER, and the second with a value of 1.

Normally application code just interacts with the OGRSpatialReference object, which uses the OGR_SRSNode to implement its data structure; however, this class is user accessible for detailed access to components of an SRS definition.

Public Functions

OGR_SRSNode(const char *pszValueIn = nullptr)

Constructor.

Parameters
  • pszValueIn: this optional parameter can be used to initialize the value of the node upon creation. If omitted the node will be created with a value of “”. Newly created OGR_SRSNodes have no children.

~OGR_SRSNode()
void RegisterListener(const std::shared_ptr<Listener> &listener)

Register a (single) listener.

int IsLeafNode() const

Return whether this is a leaf node.

Return

TRUE or FALSE

int GetChildCount() const

Get number of children nodes.

Return

0 for leaf nodes, or the number of children nodes.

OGR_SRSNode *GetChild(int iChild)

Fetch requested child.

Return

a pointer to the child OGR_SRSNode, or NULL if there is no such child.

Parameters

const OGR_SRSNode *GetChild(int iChild) const

Fetch requested child.

Return

a pointer to the child OGR_SRSNode, or NULL if there is no such child.

Parameters

OGR_SRSNode *GetNode(const char *pszName)

Find named node in tree.

This method does a pre-order traversal of the node tree searching for a node with this exact value (case insensitive), and returns it. Leaf nodes are not considered, under the assumption that they are just attribute value nodes.

If a node appears more than once in the tree (such as UNIT for instance), the first encountered will be returned. Use GetNode() on a subtree to be more specific.

Return

a pointer to the node found, or NULL if none.

Parameters
  • pszName: the name of the node to search for.

const OGR_SRSNode *GetNode(const char *pszName) const

Find named node in tree.

This method does a pre-order traversal of the node tree searching for a node with this exact value (case insensitive), and returns it. Leaf nodes are not considered, under the assumption that they are just attribute value nodes.

If a node appears more than once in the tree (such as UNIT for instance), the first encountered will be returned. Use GetNode() on a subtree to be more specific.

Return

a pointer to the node found, or NULL if none.

Parameters
  • pszName: the name of the node to search for.

void InsertChild(OGR_SRSNode *poNew, int iChild)

Insert the passed node as a child of target node, at the indicated position.

Note that ownership of the passed node is assumed by the node on which the method is invoked … use the Clone() method if the original is to be preserved. All existing children at location iChild and beyond are push down one space to make space for the new child.

Parameters
  • poNew: the node to add as a child.

  • iChild: position to insert, use 0 to insert at the beginning.

void AddChild(OGR_SRSNode *poNew)

Add passed node as a child of target node.

Note that ownership of the passed node is assumed by the node on which the method is invoked … use the Clone() method if the original is to be preserved. New children are always added at the end of the list.

Parameters
  • poNew: the node to add as a child.

int FindChild(const char *pszValueIn) const

Find the index of the child matching the given string.

Note that the node value must match pszValue with the exception of case. The comparison is case insensitive.

Return

the child index, or -1 on failure.

Parameters
  • pszValueIn: the node value being searched for.

void DestroyChild(int iChild)

Remove a child node, and it’s subtree.

Note that removing a child node will result in children after it being renumbered down one.

Parameters
  • iChild: the index of the child.

void ClearChildren()

Clear children nodes.

void StripNodes(const char *pszName)

Strip child nodes matching name.

Removes any descendant nodes of this node that match the given name. Of course children of removed nodes are also discarded.

Parameters
  • pszName: the name for nodes that should be removed.

const char *GetValue() const

Fetch value string for this node.

Return

A non-NULL string is always returned. The returned pointer is to the internal value of this node, and should not be modified, or freed.

void SetValue(const char *pszNewValue)

Set the node value.

Parameters
  • pszNewValue: the new value to assign to this node. The passed string is duplicated and remains the responsibility of the caller.

void MakeValueSafe()

Massage value string, stripping special characters so it will be a database safe string.

The operation is also applies to all subnodes of the current node.

OGR_SRSNode *Clone() const

Make a duplicate of this node, and it’s children.

Return

a new node tree, which becomes the responsibility of the caller.

OGRErr importFromWkt(char **ppszInput)

Import from WKT string.

This method will wipe the existing children and value of this node, and reassign them based on the contents of the passed WKT string. Only as much of the input string as needed to construct this node, and its children is consumed from the input string, and the input string pointer is then updated to point to the remaining (unused) input.

Return

OGRERR_NONE if import succeeds, or OGRERR_CORRUPT_DATA if it fails for any reason.

Parameters
  • ppszInput: Pointer to pointer to input. The pointer is updated to point to remaining unused input text.

OGRErr importFromWkt(const char **ppszInput)

Import from WKT string.

This method will wipe the existing children and value of this node, and reassign them based on the contents of the passed WKT string. Only as much of the input string as needed to construct this node, and its children is consumed from the input string, and the input string pointer is then updated to point to the remaining (unused) input.

Return

OGRERR_NONE if import succeeds, or OGRERR_CORRUPT_DATA if it fails for any reason.

Since

GDAL 2.3

Parameters
  • ppszInput: Pointer to pointer to input. The pointer is updated to point to remaining unused input text.

OGRErr exportToWkt(char **ppszResult) const

Convert this tree of nodes into WKT format.

Note that the returned WKT string should be freed with CPLFree() when no longer needed. It is the responsibility of the caller.

Return

currently OGRERR_NONE is always returned, but the future it is possible error conditions will develop.

Parameters
  • ppszResult: the resulting string is returned in this pointer.

OGRErr exportToPrettyWkt(char **ppszResult, int nDepth = 1) const

Convert this tree of nodes into pretty WKT format.

Note that the returned WKT string should be freed with CPLFree() when no longer needed. It is the responsibility of the caller.

Return

currently OGRERR_NONE is always returned, but the future it is possible error conditions will develop.

Parameters
  • ppszResult: the resulting string is returned in this pointer.

  • nDepth: depth of the node

Private Functions

int NeedsQuoting() const
OGRErr importFromWkt(const char **ppszInput, int nRecLevel, int *pnNodes)
void notifyChange()

Private Members

char *pszValue
OGR_SRSNode **papoChildNodes
OGR_SRSNode *poParent
int nChildren
std::weak_ptr<Listener> m_listener = {}
struct Listener
#include <ogr_spatialref.h>

Listener that is notified of modification to nodes.

Subclassed by OGRSpatialReference::Private::Listener

Public Functions

~Listener()
virtual void notifyChange(OGR_SRSNode *) = 0

Method triggered when a node is modified.

class OGRSpatialReference
#include <ogr_spatialref.h>

This class represents an OpenGIS Spatial Reference System, and contains methods for converting between this object organization and well known text (WKT) format.

This object is reference counted as one instance of the object is normally shared between many OGRGeometry objects.

Normally application code can fetch needed parameter values for this SRS using GetAttrValue(), but in special cases the underlying parse tree (or OGR_SRSNode objects) can be accessed more directly.

See the tutorial for more information on how to use this class.

Consult also the OGC WKT Coordinate System Issues page for implementation details of WKT in OGR.

Public Functions

OGRSpatialReference(const OGRSpatialReference &oOther)

Simple copy constructor.

See also Clone().

Parameters
  • oOther: other spatial reference

OGRSpatialReference(const char *pszWKT = nullptr)

Constructor.

This constructor takes an optional string argument which if passed should be a WKT representation of an SRS. Passing this is equivalent to not passing it, and then calling importFromWkt() with the WKT string.

Note that newly created objects are given a reference count of one.

The C function OSRNewSpatialReference() does the same thing as this constructor.

Parameters
  • pszWKT: well known text definition to which the object should be initialized, or NULL (the default).

~OGRSpatialReference()

OGRSpatialReference destructor.

The C function OSRDestroySpatialReference() does the same thing as this method. Preferred C++ method : OGRSpatialReference::DestroySpatialReference()

OGRSpatialReference &operator=(const OGRSpatialReference &oSource)

Assignment operator.

Return

*this

Parameters
  • oSource: SRS to assign to *this

int Reference()

Increments the reference count by one.

The reference count is used keep track of the number of OGRGeometry objects referencing this SRS.

The method does the same thing as the C function OSRReference().

Return

the updated reference count.

int Dereference()

Decrements the reference count by one.

The method does the same thing as the C function OSRDereference().

Return

the updated reference count.

int GetReferenceCount() const

Fetch current reference count.

Return

the current reference count.

void Release()

Decrements the reference count by one, and destroy if zero.

The method does the same thing as the C function OSRRelease().

const char *GetName() const

Return the CRS name.

The returned value is only short lived and should not be used after other calls to methods on this object.

Since

GDAL 3.0

OGRSpatialReference *Clone() const

Make a duplicate of this OGRSpatialReference.

This method is the same as the C function OSRClone().

Return

a new SRS, which becomes the responsibility of the caller.

OGRSpatialReference *CloneGeogCS() const

Make a duplicate of the GEOGCS node of this OGRSpatialReference object.

Return

a new SRS, which becomes the responsibility of the caller.

void dumpReadable()

Dump pretty wkt to stdout, mostly for debugging.

OGRErr exportToWkt(char **ppszResult) const

Convert this SRS into WKT 1 format.

Consult also the OGC WKT Coordinate System Issues page for implementation details of WKT 1 in OGR.

Note that the returned WKT string should be freed with CPLFree() when no longer needed. It is the responsibility of the caller.

The WKT version can be overridden by using the OSR_WKT_FORMAT configuration option. Valid values are the one of the FORMAT option of exportToWkt( char ** ppszResult, const char* const* papszOptions ) const

This method is the same as the C function OSRExportToWkt().

Return

OGRERR_NONE if successful.

Parameters
  • ppszResult: the resulting string is returned in this pointer.

OGRErr exportToWkt(char **ppszWKT, const char *const *papszOptions) const

Convert this SRS into a WKT string.

Note that the returned WKT string should be freed with CPLFree() when no longer needed. It is the responsibility of the caller.

Consult also the OGC WKT Coordinate System Issues page for implementation details of WKT 1 in OGR.

Return

OGRERR_NONE if successful.

Since

GDAL 3.0

Parameters
  • ppszResult: the resulting string is returned in this pointer.

  • papszOptions: NULL terminated list of options, or NULL. Currently supported options are

    • MULTILINE=YES/NO. Defaults to NO.

    • FORMAT=SFSQL/WKT1_SIMPLE/WKT1/WKT1_GDAL/WKT1_ESRI/WKT2_2015/WKT2_2018/WKT2/DEFAULT. If SFSQL, a WKT1 string without AXIS, TOWGS84, AUTHORITY or EXTENSION node is returned. If WKT1_SIMPLE, a WKT1 string without AXIS, AUTHORITY or EXTENSION node is returned. WKT1 is an alias of WKT1_GDAL. WKT2 will default to the latest revision implemented (currently WKT2_2018)

OGRErr exportToPrettyWkt(char **ppszResult, int bSimplify = FALSE) const

Convert this SRS into a nicely formatted WKT 1 string for display to a person.

Consult also the OGC WKT Coordinate System Issues page for implementation details of WKT 1 in OGR.

Note that the returned WKT string should be freed with CPLFree() when no longer needed. It is the responsibility of the caller.

The WKT version can be overridden by using the OSR_WKT_FORMAT configuration option. Valid values are the one of the FORMAT option of exportToWkt( char ** ppszResult, const char* const* papszOptions ) const

This method is the same as the C function OSRExportToPrettyWkt().

Return

OGRERR_NONE if successful.

Parameters
  • ppszResult: the resulting string is returned in this pointer.

  • bSimplify: TRUE if the AXIS, AUTHORITY and EXTENSION nodes should be stripped off.

OGRErr exportToPROJJSON(char **ppszResult, const char *const *papszOptions) const

Convert this SRS into a PROJJSON string.

Note that the returned WKT string should be freed with CPLFree() when no longer needed. It is the responsibility of the caller.

Return

OGRERR_NONE if successful.

Since

GDAL 3.1 and PROJ 6.2

Parameters
  • ppszResult: the resulting string is returned in this pointer.

  • papszOptions: NULL terminated list of options, or NULL. Currently supported options are

    • MULTILINE=YES/NO. Defaults to YES

    • INDENTATION_WIDTH=number. Defauls to 2 (when multiline output is on).

    • SCHEMA=string. URL to PROJJSON schema. Can be set to empty string to disable it.

OGRErr exportToProj4(char **ppszProj4) const

Export coordinate system in PROJ.4 legacy format.

Converts the loaded coordinate reference system into PROJ format to the extent possible. The string returned in ppszProj4 should be deallocated by the caller with

CPLFree() when no longer needed.
Warning

Use of this function is discouraged. Its behaviour in GDAL >= 3 / PROJ >= 6 is significantly different from earlier versions. In particular +datum will only encode WGS84, NAD27 and NAD83, and +towgs84/+nadgrids terms will be missing most of the time. PROJ strings to encode CRS should be considered as a a legacy solution. Using a AUTHORITY:CODE or WKT representation is the recommended way.

LOCAL_CS coordinate systems are not translatable. An empty string will be returned along with OGRERR_NONE.

Special processing for Transverse Mercator: Starting with GDAL 3.0, if the OSR_USE_APPROX_TMERC configuration option is set to YES, the PROJ definition built from the SRS will use the +approx flag for the tmerc and utm projection methods, rather than the more accurate method.

This method is the equivalent of the C function OSRExportToProj4().

Return

OGRERR_NONE on success or an error code on failure.

Parameters
  • ppszProj4: pointer to which dynamically allocated PROJ definition will be assigned.

OGRErr exportToPCI(char **ppszProj, char **ppszUnits, double **ppadfPrjParams) const

Export coordinate system in PCI projection definition.

Converts the loaded coordinate reference system into PCI projection definition to the extent possible. The strings returned in ppszProj, ppszUnits and ppadfPrjParams array should be deallocated by the caller with CPLFree() when no longer needed.

LOCAL_CS coordinate systems are not translatable. An empty string will be returned along with OGRERR_NONE.

This method is the equivalent of the C function OSRExportToPCI().

Return

OGRERR_NONE on success or an error code on failure.

Parameters
  • ppszProj: pointer to which dynamically allocated PCI projection definition will be assigned.

  • ppszUnits: pointer to which dynamically allocated units definition will be assigned.

  • ppadfPrjParams: pointer to which dynamically allocated array of 17 projection parameters will be assigned. See importFromPCI() for the list of parameters.

OGRErr exportToUSGS(long *piProjSys, long *piZone, double **ppadfPrjParams, long *piDatum) const

Export coordinate system in USGS GCTP projection definition.

This method is the equivalent of the C function OSRExportToUSGS().

Return

OGRERR_NONE on success or an error code on failure.

Parameters
  • piProjSys: Pointer to variable, where the projection system code will be returned.

  • piZone: Pointer to variable, where the zone for UTM and State Plane projection systems will be returned.

  • ppadfPrjParams: Pointer to which dynamically allocated array of 15 projection parameters will be assigned. See importFromUSGS() for the list of parameters. Caller responsible to free this array.

  • piDatum: Pointer to variable, where the datum code will be returned.

OGRErr exportToXML(char **ppszRawXML, const char *pszDialect = nullptr) const

Export coordinate system in XML format.

Converts the loaded coordinate reference system into XML format to the extent possible. The string returned in ppszRawXML should be deallocated by the caller with CPLFree() when no longer needed.

LOCAL_CS coordinate systems are not translatable. An empty string will be returned along with OGRERR_NONE.

This method is the equivalent of the C function OSRExportToXML().

Return

OGRERR_NONE on success or an error code on failure.

Parameters
  • ppszRawXML: pointer to which dynamically allocated XML definition will be assigned.

  • pszDialect: currently ignored. The dialect used is GML based.

OGRErr exportToPanorama(long *piProjSys, long *piDatum, long *piEllips, long *piZone, double *padfPrjParams) const

Export coordinate system in “Panorama” GIS projection definition.

This method is the equivalent of the C function OSRExportToPanorama().

Return

OGRERR_NONE on success or an error code on failure.

Parameters
  • piProjSys: Pointer to variable, where the projection system code will be returned.

  • piDatum: Pointer to variable, where the coordinate system code will be returned.

  • piEllips: Pointer to variable, where the spheroid code will be returned.

  • piZone: Pointer to variable, where the zone for UTM projection system will be returned.

  • padfPrjParams: an existing 7 double buffer into which the projection parameters will be placed. See importFromPanorama() for the list of parameters.

OGRErr exportToERM(char *pszProj, char *pszDatum, char *pszUnits)

Convert coordinate system to ERMapper format.

Return

OGRERR_NONE on success, OGRERR_SRS_UNSUPPORTED if not translation is found, or OGRERR_FAILURE on other failures.

Parameters
  • pszProj: 32 character buffer to receive projection name.

  • pszDatum: 32 character buffer to receive datum name.

  • pszUnits: 32 character buffer to receive units name.

OGRErr exportToMICoordSys(char **ppszResult) const

Export coordinate system in Mapinfo style CoordSys format.

Note that the returned WKT string should be freed with CPLFree() when no longer needed. It is the responsibility of the caller.

This method is the same as the C function OSRExportToMICoordSys().

Return

OGRERR_NONE on success, OGRERR_FAILURE on failure, OGRERR_UNSUPPORTED_OPERATION if MITAB library was not linked in.

Parameters
  • ppszResult: pointer to which dynamically allocated Mapinfo CoordSys definition will be assigned.

OGRErr importFromWkt(char **ppszInput)

Import from WKT string.

This method will wipe the existing SRS definition, and reassign it based on the contents of the passed WKT string. Only as much of the input string as needed to construct this SRS is consumed from the input string, and the input string pointer is then updated to point to the remaining (unused) input.

Consult also the OGC WKT Coordinate System Issues page for implementation details of WKT in OGR.

This method is the same as the C function OSRImportFromWkt().

Return

OGRERR_NONE if import succeeds, or OGRERR_CORRUPT_DATA if it fails for any reason.

Parameters
  • ppszInput: Pointer to pointer to input. The pointer is updated to point to remaining unused input text.

OGRErr importFromWkt(const char **ppszInput)

Import from WKT string.

This method will wipe the existing SRS definition, and reassign it based on the contents of the passed WKT string. Only as much of the input string as needed to construct this SRS is consumed from the input string, and the input string pointer is then updated to point to the remaining (unused) input.

Consult also the OGC WKT Coordinate System Issues page for implementation details of WKT in OGR.

This method is the same as the C function OSRImportFromWkt().

Return

OGRERR_NONE if import succeeds, or OGRERR_CORRUPT_DATA if it fails for any reason.

Since

GDAL 2.3

Parameters
  • ppszInput: Pointer to pointer to input. The pointer is updated to point to remaining unused input text.

OGRErr importFromWkt(const char *pszInput)

Import from WKT string.

This method will wipe the existing SRS definition, and reassign it based on the contents of the passed WKT string. Only as much of the input string as needed to construct this SRS is consumed from the input string, and the input string pointer is then updated to point to the remaining (unused) input.

Consult also the OGC WKT Coordinate System Issues page for implementation details of WKT in OGR.

Return

OGRERR_NONE if import succeeds, or OGRERR_CORRUPT_DATA if it fails for any reason.

Since

GDAL 2.3

Parameters
  • pszInput: Input WKT

OGRErr importFromProj4(const char *pszProj4)

Import PROJ coordinate string.

The OGRSpatialReference is initialized from the passed PROJs style coordinate system string.

Example: pszProj4 = “+proj=utm +zone=11 +datum=WGS84”

Some parameters, such as grids, recognized by PROJ may not be well understood and translated into the OGRSpatialReference

model. It is possible to add the +wktext parameter which is a special keyword that OGR recognized as meaning “embed the entire PROJ string in the WKT and use it literally

when converting back to PROJ format”.

For example: “+proj=nzmg +lat_0=-41 +lon_0=173 +x_0=2510000 +y_0=6023150 +ellps=intl

+units=m +nadgrids=nzgd2kgrid0005.gsb +wktext”

will be translated as :

PROJCS["unnamed",
   GEOGCS["International 1909 (Hayford)",
       DATUM["unknown",
           SPHEROID["intl",6378388,297]],
       PRIMEM["Greenwich",0],
       UNIT["degree",0.0174532925199433]],
   PROJECTION["New_Zealand_Map_Grid"],
   PARAMETER["latitude_of_origin",-41],
   PARAMETER["central_meridian",173],
   PARAMETER["false_easting",2510000],
   PARAMETER["false_northing",6023150],
   UNIT["Meter",1],
   EXTENSION["PROJ4","+proj=nzmg +lat_0=-41 +lon_0=173 +x_0=2510000
              +y_0=6023150 +ellps=intl  +units=m +nadgrids=nzgd2kgrid0005.gsb +wktext"]]

Special processing for ‘etmerc’: if +proj=etmerc is found in the passed string, the SRS built will use the WKT representation for a standard Transverse Mercator, but will aso include a PROJ4 EXTENSION node to preserve the etmerc projection method.

For example: “+proj=etmerc +lat_0=0 +lon_0=9 +k=0.9996 +units=m +x_0=500000 +datum=WGS84”

will be translated as :

PROJCS["unnamed",
    GEOGCS["WGS 84",
        DATUM["WGS_1984",
            SPHEROID["WGS 84",6378137,298.257223563,
                AUTHORITY["EPSG","7030"]],
            TOWGS84[0,0,0,0,0,0,0],
            AUTHORITY["EPSG","6326"]],
        PRIMEM["Greenwich",0,
            AUTHORITY["EPSG","8901"]],
        UNIT["degree",0.0174532925199433,
            AUTHORITY["EPSG","9108"]],
        AUTHORITY["EPSG","4326"]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",9],
    PARAMETER["scale_factor",0.9996],
    PARAMETER["false_easting",500000],
    PARAMETER["false_northing",0],
    UNIT["Meter",1],
    EXTENSION["PROJ4","+proj=etmerc +lat_0=0 +lon_0=9 +k=0.9996 +units=m +x_0=500000 +datum=WGS84 +nodefs"]]

It is also possible to import “+init=epsg:n” style definitions. Those are a legacy syntax that should be avoided in the future. In particular they will result in CRS objects whose axis order might not correspond to the official EPSG axis order.

This method is the equivalent of the C function OSRImportFromProj4().

Return

OGRERR_NONE on success or OGRERR_CORRUPT_DATA on failure.

Parameters
  • pszProj4: the PROJ style string.

OGRErr importFromEPSG(int nCode)

Initialize SRS based on EPSG geographic, projected or vertical CRS code.

This method will initialize the spatial reference based on the passed in EPSG CRS code found in the PROJ database.

This method is the same as the C function OSRImportFromEPSG().

This method try to attach a 3-parameter or 7-parameter Helmert transformation to WGS84 when there is one and only one such method available for the CRS. This behaviour might not always be desirable, so starting with GDAL 3.0.3, the OSR_ADD_TOWGS84_ON_IMPORT_FROM_EPSG configuration option can be set to NO to disable this behaviour.

Return

OGRERR_NONE on success, or an error code on failure.

Parameters
  • nCode: a GCS or PCS code from the horizontal coordinate system table.

OGRErr importFromEPSGA(int nCode)

Initialize SRS based on EPSG geographic, projected or vertical CRS code.

This method will initialize the spatial reference based on the passed in EPSG CRS code found in the PROJ database.

Since GDAL 3.0, this method is identical to importFromEPSG().

This method try to attach a 3-parameter or 7-parameter Helmert transformation to WGS84 when there is one and only one such method available for the CRS. This behaviour might not always be desirable, so starting with GDAL 3.0.3, the OSR_ADD_TOWGS84_ON_IMPORT_FROM_EPSG configuration option can be set to NO to disable this behaviour.

This method is the same as the C function OSRImportFromEPSGA().

Return

OGRERR_NONE on success, or an error code on failure.

Parameters
  • nCode: a CRS code.

OGRErr importFromESRI(char **papszPrj)

Import coordinate system from ESRI .prj format(s).

This function will read the text loaded from an ESRI .prj file, and translate it into an OGRSpatialReference definition. This should support many (but by no means all) old style (Arc/Info 7.x) .prj files, as well as the newer pseudo-OGC WKT .prj files. Note that new style .prj files are in OGC WKT format, but require some manipulation to correct datum names, and units on some projection parameters. This is addressed within importFromESRI() by an automatic call to morphFromESRI().

Currently only GEOGRAPHIC, UTM, STATEPLANE, GREATBRITIAN_GRID, ALBERS, EQUIDISTANT_CONIC, TRANSVERSE (mercator), POLAR, MERCATOR and POLYCONIC projections are supported from old style files.

At this time there is no equivalent exportToESRI() method. Writing old style .prj files is not supported by OGRSpatialReference. However the morphToESRI() and exportToWkt() methods can be used to generate output suitable to write to new style (Arc 8) .prj files.

This function is the equivalent of the C function OSRImportFromESRI().

Return

OGRERR_NONE on success or an error code in case of failure.

Parameters
  • papszPrj: NULL terminated list of strings containing the definition.

OGRErr importFromPCI(const char *pszProj, const char *pszUnits = nullptr, double *padfPrjParams = nullptr)

Import coordinate system from PCI projection definition.

PCI software uses 16-character string to specify coordinate system and datum/ellipsoid. You should supply at least this string to the importFromPCI() function.

This function is the equivalent of the C function OSRImportFromPCI().

[0] Spheroid semi major axis [1] Spheroid semi minor axis [2] Reference Longitude [3] Reference Latitude [4] First Standard Parallel [5] Second Standard Parallel [6] False Easting [7] False Northing [8] Scale Factor [9] Height above sphere surface [10] Longitude of 1st point on center line [11] Latitude of 1st point on center line [12] Longitude of 2nd point on center line [13] Latitude of 2nd point on center line [14] Azimuth east of north for center line [15] Landsat satellite number [16] Landsat path number

Parameters
  • pszProj: NULL terminated string containing the definition. Looks like “pppppppppppp Ennn” or “pppppppppppp Dnnn”, where “pppppppppppp” is a projection code, “Ennn” is an ellipsoid code, “Dnnn” a datum code.

  • pszUnits: Grid units code (“DEGREE” or “METRE”). If NULL “METRE” will be used.

  • padfPrjParams: Array of 17 coordinate system parameters:

Particular projection uses different parameters, unused ones may be set to zero. If NULL is supplied instead of an array pointer, default values will be used (i.e., zeroes).

Return

OGRERR_NONE on success or an error code in case of failure.

OGRErr importFromUSGS(long iProjSys, long iZone, double *padfPrjParams, long iDatum, int nUSGSAngleFormat = USGS_ANGLE_PACKEDDMS)

Import coordinate system from USGS projection definition.

This method will import projection definition in style, used by USGS GCTP software. GCTP operates on angles in packed DMS format (see CPLDecToPackedDMS() function for details), so all angle values (latitudes, longitudes, azimuths, etc.) specified in the padfPrjParams array should be in the packed DMS format, unless bAnglesInPackedDMSFormat is set to FALSE.

This function is the equivalent of the C function OSRImportFromUSGS(). Note that the bAnglesInPackedDMSFormat parameter is only present in the C++ method. The C function assumes bAnglesInPackedFormat = TRUE.

Projection Transformation Package Projection Parameters

Parameters
  • iProjSys: Input projection system code, used in GCTP.

  • iZone: Input zone for UTM and State Plane projection systems. For Southern Hemisphere UTM use a negative zone code. iZone ignored for all other projections.

  • padfPrjParams: Array of 15 coordinate system parameters. These parameters differs for different projections.

----------------------------------------------------------------------------
                        |                    Array Element
 Code & Projection Id   |---------------------------------------------------
                        |   0  |   1  |  2   |  3   |   4   |    5    |6 | 7
----------------------------------------------------------------------------
 0 Geographic           |      |      |      |      |       |         |  |
 1 U T M                |Lon/Z |Lat/Z |      |      |       |         |  |
 2 State Plane          |      |      |      |      |       |         |  |
 3 Albers Equal Area    |SMajor|SMinor|STDPR1|STDPR2|CentMer|OriginLat|FE|FN
 4 Lambert Conformal C  |SMajor|SMinor|STDPR1|STDPR2|CentMer|OriginLat|FE|FN
 5 Mercator             |SMajor|SMinor|      |      |CentMer|TrueScale|FE|FN
 6 Polar Stereographic  |SMajor|SMinor|      |      |LongPol|TrueScale|FE|FN
 7 Polyconic            |SMajor|SMinor|      |      |CentMer|OriginLat|FE|FN
 8 Equid. Conic A       |SMajor|SMinor|STDPAR|      |CentMer|OriginLat|FE|FN
   Equid. Conic B       |SMajor|SMinor|STDPR1|STDPR2|CentMer|OriginLat|FE|FN
 9 Transverse Mercator  |SMajor|SMinor|Factor|      |CentMer|OriginLat|FE|FN
10 Stereographic        |Sphere|      |      |      |CentLon|CenterLat|FE|FN
11 Lambert Azimuthal    |Sphere|      |      |      |CentLon|CenterLat|FE|FN
12 Azimuthal            |Sphere|      |      |      |CentLon|CenterLat|FE|FN
13 Gnomonic             |Sphere|      |      |      |CentLon|CenterLat|FE|FN
14 Orthographic         |Sphere|      |      |      |CentLon|CenterLat|FE|FN
15 Gen. Vert. Near Per  |Sphere|      |Height|      |CentLon|CenterLat|FE|FN
16 Sinusoidal           |Sphere|      |      |      |CentMer|         |FE|FN
17 Equirectangular      |Sphere|      |      |      |CentMer|TrueScale|FE|FN
18 Miller Cylindrical   |Sphere|      |      |      |CentMer|         |FE|FN
19 Van der Grinten      |Sphere|      |      |      |CentMer|OriginLat|FE|FN
20 Hotin Oblique Merc A |SMajor|SMinor|Factor|      |       |OriginLat|FE|FN
   Hotin Oblique Merc B |SMajor|SMinor|Factor|AziAng|AzmthPt|OriginLat|FE|FN
21 Robinson             |Sphere|      |      |      |CentMer|         |FE|FN
22 Space Oblique Merc A |SMajor|SMinor|      |IncAng|AscLong|         |FE|FN
   Space Oblique Merc B |SMajor|SMinor|Satnum|Path  |       |         |FE|FN
23 Alaska Conformal     |SMajor|SMinor|      |      |       |         |FE|FN
24 Interrupted Goode    |Sphere|      |      |      |       |         |  |
25 Mollweide            |Sphere|      |      |      |CentMer|         |FE|FN
26 Interrupt Mollweide  |Sphere|      |      |      |       |         |  |
27 Hammer               |Sphere|      |      |      |CentMer|         |FE|FN
28 Wagner IV            |Sphere|      |      |      |CentMer|         |FE|FN
29 Wagner VII           |Sphere|      |      |      |CentMer|         |FE|FN
30 Oblated Equal Area   |Sphere|      |Shapem|Shapen|CentLon|CenterLat|FE|FN
----------------------------------------------------------------------------

      ----------------------------------------------------
                              |      Array Element       |
        Code & Projection Id  |---------------------------
                              |  8  |  9 |  10 | 11 | 12 |
      ----------------------------------------------------
       0 Geographic           |     |    |     |    |    |
       1 U T M                |     |    |     |    |    |
       2 State Plane          |     |    |     |    |    |
       3 Albers Equal Area    |     |    |     |    |    |
       4 Lambert Conformal C  |     |    |     |    |    |
       5 Mercator             |     |    |     |    |    |
       6 Polar Stereographic  |     |    |     |    |    |
       7 Polyconic            |     |    |     |    |    |
       8 Equid. Conic A       |zero |    |     |    |    |
         Equid. Conic B       |one  |    |     |    |    |
       9 Transverse Mercator  |     |    |     |    |    |
      10 Stereographic        |     |    |     |    |    |
      11 Lambert Azimuthal    |     |    |     |    |    |
      12 Azimuthal            |     |    |     |    |    |
      13 Gnomonic             |     |    |     |    |    |
      14 Orthographic         |     |    |     |    |    |
      15 Gen. Vert. Near Per  |     |    |     |    |    |
      16 Sinusoidal           |     |    |     |    |    |
      17 Equirectangular      |     |    |     |    |    |
      18 Miller Cylindrical   |     |    |     |    |    |
      19 Van der Grinten      |     |    |     |    |    |
      20 Hotin Oblique Merc A |Long1|Lat1|Long2|Lat2|zero|
         Hotin Oblique Merc B |     |    |     |    |one |
      21 Robinson             |     |    |     |    |    |
      22 Space Oblique Merc A |PSRev|LRat|PFlag|    |zero|
         Space Oblique Merc B |     |    |     |    |one |
      23 Alaska Conformal     |     |    |     |    |    |
      24 Interrupted Goode    |     |    |     |    |    |
      25 Mollweide            |     |    |     |    |    |
      26 Interrupt Mollweide  |     |    |     |    |    |
      27 Hammer               |     |    |     |    |    |
      28 Wagner IV            |     |    |     |    |    |
      29 Wagner VII           |     |    |     |    |    |
      30 Oblated Equal Area   |Angle|    |     |    |    |
      ----------------------------------------------------

  where

   Lon/Z     Longitude of any point in the UTM zone or zero.  If zero,
             a zone code must be specified.
   Lat/Z     Latitude of any point in the UTM zone or zero.  If zero, a
             zone code must be specified.
   SMajor    Semi-major axis of ellipsoid.  If zero, Clarke 1866 in meters
             is assumed.
   SMinor    Eccentricity squared of the ellipsoid if less than zero,
             if zero, a spherical form is assumed, or if greater than
             zero, the semi-minor axis of ellipsoid.
   Sphere    Radius of reference sphere.  If zero, 6370997 meters is used.
   STDPAR    Latitude of the standard parallel
   STDPR1    Latitude of the first standard parallel
   STDPR2    Latitude of the second standard parallel
   CentMer   Longitude of the central meridian
   OriginLat Latitude of the projection origin
   FE        False easting in the same units as the semi-major axis
   FN        False northing in the same units as the semi-major axis
   TrueScale Latitude of true scale
   LongPol   Longitude down below pole of map
   Factor    Scale factor at central meridian (Transverse Mercator) or
             center of projection (Hotine Oblique Mercator)
   CentLon   Longitude of center of projection
   CenterLat Latitude of center of projection
   Height    Height of perspective point
   Long1     Longitude of first point on center line (Hotine Oblique
             Mercator, format A)
   Long2     Longitude of second point on center line (Hotine Oblique
             Mercator, format A)
   Lat1      Latitude of first point on center line (Hotine Oblique
             Mercator, format A)
   Lat2      Latitude of second point on center line (Hotine Oblique
             Mercator, format A)
   AziAng    Azimuth angle east of north of center line (Hotine Oblique
             Mercator, format B)
   AzmthPt   Longitude of point on central meridian where azimuth occurs
             (Hotine Oblique Mercator, format B)
   IncAng    Inclination of orbit at ascending node, counter-clockwise
             from equator (SOM, format A)
   AscLong   Longitude of ascending orbit at equator (SOM, format A)
   PSRev     Period of satellite revolution in minutes (SOM, format A)
   LRat      Landsat ratio to compensate for confusion at northern end
             of orbit (SOM, format A -- use 0.5201613)
   PFlag     End of path flag for Landsat:  0 = start of path,
             1 = end of path (SOM, format A)
   Satnum    Landsat Satellite Number (SOM, format B)
   Path      Landsat Path Number (Use WRS-1 for Landsat 1, 2 and 3 and
             WRS-2 for Landsat 4, 5 and 6.)  (SOM, format B)
   Shapem    Oblated Equal Area oval shape parameter m
   Shapen    Oblated Equal Area oval shape parameter n
   Angle     Oblated Equal Area oval rotation angle

Array elements 13 and 14 are set to zero. All array elements with blank
fields are set to zero too.

Parameters
  • iDatum: Input spheroid.

If the datum code is negative, the first two values in the parameter array (parm) are used to define the values as follows:

  • If padfPrjParams[0] is a non-zero value and padfPrjParams[1] is greater than one, the semimajor axis is set to padfPrjParams[0] and the semiminor axis is set to padfPrjParams[1].

  • If padfPrjParams[0] is nonzero and padfPrjParams[1] is greater than zero but less than or equal to one, the semimajor axis is set to padfPrjParams[0] and the semiminor axis is computed from the eccentricity squared value padfPrjParams[1]:

    semiminor = sqrt(1.0 - ES) * semimajor

    where

    ES = eccentricity squared

  • If padfPrjParams[0] is nonzero and padfPrjParams[1] is equal to zero, the semimajor axis and semiminor axis are set to padfPrjParams[0].

  • If padfPrjParams[0] equals zero and padfPrjParams[1] is greater than zero, the default Clarke 1866 is used to assign values to the semimajor axis and semiminor axis.

  • If padfPrjParams[0] and padfPrjParams[1] equals zero, the semimajor axis is set to 6370997.0 and the semiminor axis is set to zero.

If a datum code is zero or greater, the semimajor and semiminor axis are defined by the datum code as found in the following table:

Supported Datums

 0: Clarke 1866 (default)
 1: Clarke 1880
 2: Bessel
 3: International 1967
 4: International 1909
 5: WGS 72
 6: Everest
 7: WGS 66
 8: GRS 1980/WGS 84
 9: Airy
10: Modified Everest
11: Modified Airy
12: WGS 84
13: Southeast Asia
14: Australian National
15: Krassovsky
16: Hough
17: Mercury 1960
18: Modified Mercury 1968
19: Sphere of Radius 6370997 meters

Return

OGRERR_NONE on success or an error code in case of failure.

Parameters
  • nUSGSAngleFormat: one of USGS_ANGLE_DECIMALDEGREES, USGS_ANGLE_PACKEDDMS, or USGS_ANGLE_RADIANS (default is USGS_ANGLE_PACKEDDMS).

OGRErr importFromPanorama(long iProjSys, long iDatum, long iEllips, double *padfPrjParams)

Import coordinate system from “Panorama” GIS projection definition.

This method will import projection definition in style, used by “Panorama” GIS.

This function is the equivalent of the C function OSRImportFromPanorama().

[0]  Latitude of the first standard parallel (radians)
[1]  Latitude of the second standard parallel (radians)
[2]  Latitude of center of projection (radians)
[3]  Longitude of center of projection (radians)
[4]  Scaling factor
[5]  False Easting
[6]  False Northing
[7]  Zone number
Parameters
  • iProjSys: Input projection system code, used in GIS “Panorama”.

     <h4>Supported Projections</h4>
    
    1:  Gauss-Kruger (Transverse Mercator)
    2:  Lambert Conformal Conic 2SP
    5:  Stereographic
    6:  Azimuthal Equidistant (Postel)
    8:  Mercator
    10: Polyconic
    13: Polar Stereographic
    15: Gnomonic
    17: Universal Transverse Mercator (UTM)
    18: Wagner I (Kavraisky VI)
    19: Mollweide
    20: Equidistant Conic
    24: Lambert Azimuthal Equal Area
    27: Equirectangular
    28: Cylindrical Equal Area (Lambert)
    29: International Map of the World Polyconic
    

  • iDatum: Input coordinate system.

     <h4>Supported Datums</h4>
    
    1: Pulkovo, 1942
    2: WGS, 1984
    3: OSGB 1936 (British National Grid)
    9: Pulkovo, 1995
    

  • iEllips: Input spheroid.

     <h4>Supported Spheroids</h4>
    
    1: Krassovsky, 1940
    2: WGS, 1972
    3: International, 1924 (Hayford, 1909)
    4: Clarke, 1880
    5: Clarke, 1866 (NAD1927)
    6: Everest, 1830
    7: Bessel, 1841
    8: Airy, 1830
    9: WGS, 1984 (GPS)
    

  • padfPrjParams: Array of 8 coordinate system parameters:

Particular projection uses different parameters, unused ones may be set to zero. If NULL supplied instead of array pointer default values will be used (i.e., zeroes).

Return

OGRERR_NONE on success or an error code in case of failure.

OGRErr importFromOzi(const char *const *papszLines)

Import coordinate system from OziExplorer projection definition.

This method will import projection definition in style, used by OziExplorer software.

Return

OGRERR_NONE on success or an error code in case of failure.

Since

OGR 1.10

Parameters
  • papszLines: Map file lines. This is an array of strings containing the whole OziExplorer .MAP file. The array is terminated by a NULL pointer.

OGRErr importFromWMSAUTO(const char *pszAutoDef)

Initialize from WMSAUTO string.

Note that the WMS 1.3 specification does not include the units code, while apparently earlier specs do. We try to guess around this.

Return

OGRERR_NONE on success or an error code.

Parameters
  • pszDefinition: the WMSAUTO string

OGRErr importFromXML(const char *pszXML)

Import coordinate system from XML format (GML only currently).

This method is the same as the C function OSRImportFromXML()

Return

OGRERR_NONE on success or OGRERR_CORRUPT_DATA on failure.

Parameters
  • pszXML: XML string to import

OGRErr importFromDict(const char *pszDict, const char *pszCode)

Read SRS from WKT dictionary.

This method will attempt to find the indicated coordinate system identity in the indicated dictionary file. If found, the WKT representation is imported and used to initialize this OGRSpatialReference.

More complete information on the format of the dictionary files can be found in the epsg.wkt file in the GDAL data tree. The dictionary files are searched for in the “GDAL” domain using CPLFindFile(). Normally this results in searching /usr/local/share/gdal or somewhere similar.

This method is the same as the C function OSRImportFromDict().

Return

OGRERR_NONE on success, or OGRERR_SRS_UNSUPPORTED if the code isn’t found, and OGRERR_SRS_FAILURE if something more dramatic goes wrong.

Parameters
  • pszDictFile: the name of the dictionary file to load.

  • pszCode: the code to lookup in the dictionary.

OGRErr importFromURN(const char *pszURN)

Initialize from OGC URN.

Initializes this spatial reference from a coordinate system defined by an OGC URN prefixed with “urn:ogc:def:crs:” per recommendation paper 06-023r1. Currently EPSG and OGC authority values are supported, including OGC auto codes, but not including CRS1 or CRS88 (NAVD88).

This method is also support through SetFromUserInput() which can normally be used for URNs.

Return

OGRERR_NONE on success or an error code.

Parameters
  • pszURN: the urn string.

OGRErr importFromCRSURL(const char *pszURL)

Initialize from OGC URL.

Initializes this spatial reference from a coordinate system defined by an OGC URL prefixed with “http://opengis.net/def/crs” per best practice paper 11-135. Currently EPSG and OGC authority values are supported, including OGC auto codes, but not including CRS1 or CRS88 (NAVD88).

This method is also supported through SetFromUserInput() which can normally be used for URLs.

Return

OGRERR_NONE on success or an error code.

Parameters
  • pszURL: the URL string.

OGRErr importFromERM(const char *pszProj, const char *pszDatum, const char *pszUnits)

Create OGR WKT from ERMapper projection definitions.

Generates an OGRSpatialReference definition from an ERMapper datum and projection name. Based on the ecw_cs.wkt dictionary file from gdal/data.

Return

OGRERR_NONE on success or OGRERR_UNSUPPORTED_SRS if not found.

Parameters
  • pszProj: the projection name, such as “NUTM11” or “GEOGRAPHIC”.

  • pszDatum: the datum name, such as “NAD83”.

  • pszUnits: the linear units “FEET” or “METERS”.

OGRErr importFromUrl(const char *pszUrl)

Set spatial reference from a URL.

This method will download the spatial reference at a given URL and feed it into SetFromUserInput for you.

This method does the same thing as the OSRImportFromUrl() function.

Return

OGRERR_NONE on success, or an error code with the curl error message if it is unable to dowload data.

Parameters
  • pszUrl: text definition to try to deduce SRS from.

OGRErr importFromMICoordSys(const char *pszCoordSys)

Import Mapinfo style CoordSys definition.

The OGRSpatialReference is initialized from the passed Mapinfo style CoordSys definition string.

This method is the equivalent of the C function OSRImportFromMICoordSys().

Return

OGRERR_NONE on success, OGRERR_FAILURE on failure, OGRERR_UNSUPPORTED_OPERATION if MITAB library was not linked in.

Parameters
  • pszCoordSys: Mapinfo style CoordSys definition string.

OGRErr morphToESRI()

Convert in place to ESRI WKT format.

The value nodes of this coordinate system are modified in various manners more closely map onto the ESRI concept of WKT format. This includes renaming a variety of projections and arguments, and stripping out nodes note recognised by ESRI (like AUTHORITY and AXIS).

This does the same as the C function

OSRMorphToESRI().
Note

Since GDAL 3.0, this function has only user-visible effects at exportToWkt() time. It is recommended to use instead exportToWkt(char**, const char* const char*) const with options having FORMAT=WKT1_ESRI.

Return

OGRERR_NONE unless something goes badly wrong.

OGRErr morphFromESRI()

Convert in place from ESRI WKT format.

The value notes of this coordinate system are modified in various manners to adhere more closely to the WKT standard. This mostly involves translating a variety of ESRI names for projections, arguments and datums to “standard” names, as defined by Adam Gawne-Cain’s reference translation of EPSG to WKT for the CT specification.

This does the same as the C function

OSRMorphFromESRI().
Note

Since GDAL 3.0, this function is essentially a no-operation, since morphing from ESRI is automatically done by importFromWkt(). Its only effect is to undo the effect of a potential prior call to morphToESRI().

Return

OGRERR_NONE unless something goes badly wrong.

OGRSpatialReference *convertToOtherProjection(const char *pszTargetProjection, const char *const *papszOptions = nullptr) const

Convert to another equivalent projection.

Currently implemented:

  • SRS_PT_MERCATOR_1SP to SRS_PT_MERCATOR_2SP

  • SRS_PT_MERCATOR_2SP to SRS_PT_MERCATOR_1SP

  • SRS_PT_LAMBERT_CONFORMAL_CONIC_1SP to SRS_PT_LAMBERT_CONFORMAL_CONIC_2SP

  • SRS_PT_LAMBERT_CONFORMAL_CONIC_2SP to SRS_PT_LAMBERT_CONFORMAL_CONIC_1SP

Return

a new SRS, or NULL in case of error.

Since

GDAL 2.3

Parameters
  • pszTargetProjection: target projection.

  • papszOptions: lists of options. None supported currently.

OGRErr Validate() const

Validate CRS imported with importFromWkt() or with modified with direct node manipulations.

Otherwise the CRS should be always valid.

This method attempts to verify that the spatial reference system is well formed, and consists of known tokens. The validation is not comprehensive.

This method is the same as the C function OSRValidate().

Return

OGRERR_NONE if all is fine, OGRERR_CORRUPT_DATA if the SRS is not well formed, and OGRERR_UNSUPPORTED_SRS if the SRS is well formed, but contains non-standard PROJECTION[] values.

OGRErr StripVertical()

Convert a compound cs into a horizontal CS.

If this SRS is of type COMPD_CS[] then the vertical CS and the root COMPD_CS nodes are stripped resulting and only the horizontal coordinate system portion remains (normally PROJCS, GEOGCS or LOCAL_CS).

If this is not a compound coordinate system then nothing is changed.

Since

OGR 1.8.0

int EPSGTreatsAsLatLong() const

This method returns TRUE if EPSG feels this geographic coordinate system should be treated as having lat/long coordinate ordering.

Currently this returns TRUE for all geographic coordinate systems with an EPSG code set, and axes set defining it as lat, long.

FALSE will be returned for all coordinate systems that are not geographic, or that do not have an EPSG code set.

Note

Important change of behaviour since GDAL 3.0. In previous versions, geographic CRS imported with importFromEPSG() would cause this method to return FALSE on them, whereas now it returns TRUE, since importFromEPSG() is now equivalent to importFromEPSGA().

This method is the same as the C function OSREPSGTreatsAsLatLong().

Return

TRUE or FALSE.

int EPSGTreatsAsNorthingEasting() const

This method returns TRUE if EPSG feels this projected coordinate system should be treated as having northing/easting coordinate ordering.

Currently this returns TRUE for all projected coordinate systems with an EPSG code set, and axes set defining it as northing, easting.

FALSE will be returned for all coordinate systems that are not projected, or that do not have an EPSG code set.

Note

Important change of behaviour since GDAL 3.0. In previous versions, projected CRS with northing, easting axis order imported with importFromEPSG() would cause this method to return FALSE on them, whereas now it returns TRUE, since importFromEPSG() is now equivalent to importFromEPSGA().

This method is the same as the C function EPSGTreatsAsNorthingEasting().

Return

TRUE or FALSE.

Since

OGR 1.10.0

int GetAxesCount() const

Return the number of axis of the coordinate system of the CRS.

Since

GDAL 3.0

const char *GetAxis(const char *pszTargetKey, int iAxis, OGRAxisOrientation *peOrientation) const

Fetch the orientation of one axis.

Fetches the request axis (iAxis - zero based) from the indicated portion of the coordinate system (pszTargetKey) which should be either “GEOGCS” or “PROJCS”.

No CPLError is issued on routine failures (such as not finding the AXIS).

This method is equivalent to the C function OSRGetAxis().

Return

the name of the axis or NULL on failure.

Parameters
  • pszTargetKey: the coordinate system part to query (“PROJCS” or “GEOGCS”).

  • iAxis: the axis to query (0 for first, 1 for second).

  • peOrientation: location into which to place the fetch orientation, may be NULL.

OGRErr SetAxes(const char *pszTargetKey, const char *pszXAxisName, OGRAxisOrientation eXAxisOrientation, const char *pszYAxisName, OGRAxisOrientation eYAxisOrientation)

Set the axes for a coordinate system.

Set the names, and orientations of the axes for either a projected (PROJCS) or geographic (GEOGCS) coordinate system.

This method is equivalent to the C function OSRSetAxes().

Return

OGRERR_NONE on success or an error code.

Parameters
  • pszTargetKey: either “PROJCS” or “GEOGCS”, must already exist in SRS.

  • pszXAxisName: name of first axis, normally “Long” or “Easting”.

  • eXAxisOrientation: normally OAO_East.

  • pszYAxisName: name of second axis, normally “Lat” or “Northing”.

  • eYAxisOrientation: normally OAO_North.

OSRAxisMappingStrategy GetAxisMappingStrategy() const

Retun the data axis to CRS axis mapping strategy.

  • OAMS_TRADITIONAL_GIS_ORDER means that for geographic CRS with lat/long order, the data will still be long/lat ordered. Similarly for a projected CRS with northing/easting order, the data will still be easting/northing ordered.

  • OAMS_AUTHORITY_COMPLIANT means that the data axis will be identical to the CRS axis.

  • OAMS_CUSTOM means that the data axis are customly defined with SetDataAxisToSRSAxisMapping()

Return

the the data axis to CRS axis mapping strategy.

Since

GDAL 3.0

void SetAxisMappingStrategy(OSRAxisMappingStrategy strategy)

Set the data axis to CRS axis mapping strategy.

See OGRSpatialReference::GetAxisMappingStrategy()

Since

GDAL 3.0

const std::vector<int> &GetDataAxisToSRSAxisMapping() const

Return the data axis to SRS axis mapping.

The number of elements of the vector will be the number of axis of the CRS. Values start at 1.

If m = GetDataAxisToSRSAxisMapping(), then m[0] is the data axis number for the first axis of the CRS.

Since

GDAL 3.0

OGRErr SetDataAxisToSRSAxisMapping(const std::vector<int> &mapping)

Set a custom data axis to CRS axis mapping.

Automatically implies SetAxisMappingStrategy(OAMS_CUSTOM)

See OGRSpatialReference::GetAxisMappingStrategy()

Since

GDAL 3.0

OGR_SRSNode *GetRoot()

Return root node.

const OGR_SRSNode *GetRoot() const

Return root node.

void SetRoot(OGR_SRSNode *poNewRoot)

Set the root SRS node.

If the object has an existing tree of OGR_SRSNodes, they are destroyed as part of assigning the new root. Ownership of the passed OGR_SRSNode is is assumed by the OGRSpatialReference.

Parameters
  • poNewRoot: object to assign as root.

OGR_SRSNode *GetAttrNode(const char *pszNodePath)

Find named node in tree.

This method does a pre-order traversal of the node tree searching for a node with this exact value (case insensitive), and returns it. Leaf nodes are not considered, under the assumption that they are just attribute value nodes.

If a node appears more than once in the tree (such as UNIT for instance), the first encountered will be returned. Use GetNode() on a subtree to be more specific.

Return

a pointer to the node found, or NULL if none.

Parameters
  • pszNodePath: the name of the node to search for. May contain multiple components such as “GEOGCS|UNIT”.

const OGR_SRSNode *GetAttrNode(const char *pszNodePath) const

Find named node in tree.

This method does a pre-order traversal of the node tree searching for a node with this exact value (case insensitive), and returns it. Leaf nodes are not considered, under the assumption that they are just attribute value nodes.

If a node appears more than once in the tree (such as UNIT for instance), the first encountered will be returned. Use GetNode() on a subtree to be more specific.

Return

a pointer to the node found, or NULL if none.

Parameters
  • pszNodePath: the name of the node to search for. May contain multiple components such as “GEOGCS|UNIT”.

const char *GetAttrValue(const char *pszNodeName, int iAttr = 0) const

Fetch indicated attribute of named node.

This method uses GetAttrNode() to find the named node, and then extracts the value of the indicated child. Thus a call to GetAttrValue(“UNIT”,1) would return the second child of the UNIT node, which is normally the length of the linear unit in meters.

This method does the same thing as the C function OSRGetAttrValue().

Return

the requested value, or NULL if it fails for any reason.

Parameters
  • pszNodeName: the tree node to look for (case insensitive).

  • iAttr: the child of the node to fetch (zero based).

OGRErr SetNode(const char *pszNodePath, const char *pszNewNodeValue)

Set attribute value in spatial reference.

Missing intermediate nodes in the path will be created if not already in existence. If the attribute has no children one will be created and assigned the value otherwise the zeroth child will be assigned the value.

This method does the same as the C function OSRSetAttrValue().

Return

OGRERR_NONE on success.

Parameters
  • pszNodePath: full path to attribute to be set. For instance “PROJCS|GEOGCS|UNIT”.

  • pszNewNodeValue: value to be assigned to node, such as “meter”. This may be NULL if you just want to force creation of the intermediate path.

OGRErr SetNode(const char *pszNodePath, double dfValue)

Set attribute value in spatial reference.

Missing intermediate nodes in the path will be created if not already in existence. If the attribute has no children one will be created and assigned the value otherwise the zeroth child will be assigned the value.

This method does the same as the C function OSRSetAttrValue().

Return

OGRERR_NONE on success.

Parameters
  • pszNodePath: full path to attribute to be set. For instance “PROJCS|GEOGCS|UNIT”.

  • dfValue: value to be assigned to node.

OGRErr SetLinearUnitsAndUpdateParameters(const char *pszName, double dfInMeters, const char *pszUnitAuthority = nullptr, const char *pszUnitCode = nullptr)

Set the linear units for the projection.

This method creates a UNIT subnode with the specified values as a child of the PROJCS or LOCAL_CS node. It works the same as the SetLinearUnits() method, but it also updates all existing linear projection parameter values from the old units to the new units.

Return

OGRERR_NONE on success.

Parameters
  • pszName: the units name to be used. Some preferred units names can be found in ogr_srs_api.h such as SRS_UL_METER, SRS_UL_FOOT and SRS_UL_US_FOOT.

  • dfInMeters: the value to multiple by a length in the indicated units to transform to meters. Some standard conversion factors can be found in ogr_srs_api.h.

  • pszUnitAuthority: Unit authority name. Or nullptr

  • pszUnitCode: Unit code. Or nullptr

OGRErr SetLinearUnits(const char *pszName, double dfInMeters)

Set the linear units for the projection.

This method creates a UNIT subnode with the specified values as a child of the PROJCS, GEOCCS or LOCAL_CS node.

This method does the same as the C function OSRSetLinearUnits().

Return

OGRERR_NONE on success.

Parameters
  • pszUnitsName: the units name to be used. Some preferred units names can be found in ogr_srs_api.h such as SRS_UL_METER, SRS_UL_FOOT and SRS_UL_US_FOOT.

  • dfInMeters: the value to multiple by a length in the indicated units to transform to meters. Some standard conversion factors can be found in ogr_srs_api.h.

OGRErr SetTargetLinearUnits(const char *pszTargetKey, const char *pszName, double dfInMeters, const char *pszUnitAuthority = nullptr, const char *pszUnitCode = nullptr)

Set the linear units for the projection.

This method creates a UNIT subnode with the specified values as a child of the target node.

This method does the same as the C function OSRSetTargetLinearUnits().

Return

OGRERR_NONE on success.

Since

OGR 1.9.0

Parameters
  • pszTargetKey: the keyword to set the linear units for. i.e. “PROJCS” or “VERT_CS”

  • pszUnitsName: the units name to be used. Some preferred units names can be found in ogr_srs_api.h such as SRS_UL_METER, SRS_UL_FOOT and SRS_UL_US_FOOT.

  • dfInMeters: the value to multiple by a length in the indicated units to transform to meters. Some standard conversion factors can be found in ogr_srs_api.h.

  • pszUnitAuthority: Unit authority name. Or nullptr

  • pszUnitCode: Unit code. Or nullptr

double GetLinearUnits(char **ppszName) const

Fetch linear projection units.

If no units are available, a value of “Meters” and 1.0 will be assumed. This method only checks directly under the PROJCS, GEOCCS or LOCAL_CS node for units.

This method does the same thing as the C function OSRGetLinearUnits()

Return

the value to multiply by linear distances to transform them to meters.

Parameters
  • ppszName: a pointer to be updated with the pointer to the units name. The returned value remains internal to the OGRSpatialReference and should not be freed, or modified. It may be invalidated on the next OGRSpatialReference call.

double GetLinearUnits(const char **ppszName = nullptr) const

Fetch linear projection units.

If no units are available, a value of “Meters” and 1.0 will be assumed. This method only checks directly under the PROJCS, GEOCCS or LOCAL_CS node for units.

This method does the same thing as the C function OSRGetLinearUnits()

Return

the value to multiply by linear distances to transform them to meters.

Since

GDAL 2.3.0

Parameters
  • ppszName: a pointer to be updated with the pointer to the units name. The returned value remains internal to the OGRSpatialReference and should not be freed, or modified. It may be invalidated on the next OGRSpatialReference call.

double GetTargetLinearUnits(const char *pszTargetKey, char **ppszRetName) const

Fetch linear units for target.

If no units are available, a value of “Meters” and 1.0 will be assumed.

This method does the same thing as the C function OSRGetTargetLinearUnits()

Return

the value to multiply by linear distances to transform them to meters.

Since

GDAL 2.3.0

Parameters
  • pszTargetKey: the key to look on. i.e. “PROJCS” or “VERT_CS”. Might be NULL, in which case PROJCS will be implied (and if not found, LOCAL_CS, GEOCCS and VERT_CS are looked up)

  • ppszName: a pointer to be updated with the pointer to the units name. The returned value remains internal to the OGRSpatialReference and should not be freed, or modified. It may be invalidated on the next OGRSpatialReference call. ppszName can be set to NULL.

double GetTargetLinearUnits(const char *pszTargetKey, const char **ppszRetName = nullptr) const

Fetch linear units for target.

If no units are available, a value of “Meters” and 1.0 will be assumed.

This method does the same thing as the C function OSRGetTargetLinearUnits()

Return

the value to multiply by linear distances to transform them to meters.

Since

OGR 1.9.0

Parameters
  • pszTargetKey: the key to look on. i.e. “PROJCS” or “VERT_CS”. Might be NULL, in which case PROJCS will be implied (and if not found, LOCAL_CS, GEOCCS and VERT_CS are looked up)

  • ppszName: a pointer to be updated with the pointer to the units name. The returned value remains internal to the OGRSpatialReference and should not be freed, or modified. It may be invalidated on the next OGRSpatialReference call. ppszName can be set to NULL.

OGRErr SetAngularUnits(const char *pszName, double dfInRadians)

Set the angular units for the geographic coordinate system.

This method creates a UNIT subnode with the specified values as a child of the GEOGCS node.

This method does the same as the C function OSRSetAngularUnits().

Return

OGRERR_NONE on success.

Parameters
  • pszUnitsName: the units name to be used. Some preferred units names can be found in ogr_srs_api.h such as SRS_UA_DEGREE.

  • dfInRadians: the value to multiple by an angle in the indicated units to transform to radians. Some standard conversion factors can be found in ogr_srs_api.h.

double GetAngularUnits(char **ppszName) const

Fetch angular geographic coordinate system units.

If no units are available, a value of “degree” and SRS_UA_DEGREE_CONV will be assumed. This method only checks directly under the GEOGCS node for units.

This method does the same thing as the C function OSRGetAngularUnits().

Return

the value to multiply by angular distances to transform them to radians.

Since

GDAL 2.3.0

Parameters
  • ppszName: a pointer to be updated with the pointer to the units name. The returned value remains internal to the OGRSpatialReference and should not be freed, or modified. It may be invalidated on the next OGRSpatialReference call.

double GetAngularUnits(const char **ppszName = nullptr) const

Fetch angular geographic coordinate system units.

If no units are available, a value of “degree” and SRS_UA_DEGREE_CONV will be assumed. This method only checks directly under the GEOGCS node for units.

This method does the same thing as the C function OSRGetAngularUnits().

Return

the value to multiply by angular distances to transform them to radians.

Parameters
  • ppszName: a pointer to be updated with the pointer to the units name. The returned value remains internal to the OGRSpatialReference and should not be freed, or modified. It may be invalidated on the next OGRSpatialReference call.

double GetPrimeMeridian(char **ppszName) const

Fetch prime meridian info.

Returns the offset of the prime meridian from greenwich in degrees, and the prime meridian name (if requested). If no PRIMEM value exists in the coordinate system definition a value of “Greenwich” and an offset of 0.0 is assumed.

If the prime meridian name is returned, the pointer is to an internal copy of the name. It should not be freed, altered or depended on after the next OGR call.

This method is the same as the C function OSRGetPrimeMeridian().

Return

the offset to the GEOGCS prime meridian from greenwich in decimal degrees.

Since

GDAL 2.3.0

Parameters
  • ppszName: return location for prime meridian name. If NULL, name is not returned.

double GetPrimeMeridian(const char **ppszName = nullptr) const

Fetch prime meridian info.

Returns the offset of the prime meridian from greenwich in degrees, and the prime meridian name (if requested). If no PRIMEM value exists in the coordinate system definition a value of “Greenwich” and an offset of 0.0 is assumed.

If the prime meridian name is returned, the pointer is to an internal copy of the name. It should not be freed, altered or depended on after the next OGR call.

This method is the same as the C function OSRGetPrimeMeridian().

Return

the offset to the GEOGCS prime meridian from greenwich in decimal degrees.

Parameters
  • ppszName: return location for prime meridian name. If NULL, name is not returned.

bool IsEmpty() const

Return if the SRS is not set.

int IsGeographic() const

Check if geographic coordinate system.

This method is the same as the C function OSRIsGeographic().

Return

TRUE if this spatial reference is geographic … that is the root is a GEOGCS node. Also if it is a CompoundCRS made of a GeographicCRS

int IsProjected() const

Check if projected coordinate system.

This method is the same as the C function OSRIsProjected().

Return

TRUE if this contains a PROJCS node indicating a it is a projected coordinate system. Also if it is a CompoundCRS made of a ProjectedCRS

int IsGeocentric() const

Check if geocentric coordinate system.

This method is the same as the C function OSRIsGeocentric().

Return

TRUE if this contains a GEOCCS node indicating a it is a geocentric coordinate system.

Since

OGR 1.9.0

int IsLocal() const

Check if local coordinate system.

This method is the same as the C function OSRIsLocal().

Return

TRUE if this spatial reference is local … that is the root is a LOCAL_CS node.

int IsVertical() const

Check if vertical coordinate system.

This method is the same as the C function OSRIsVertical().

Return

TRUE if this contains a VERT_CS node indicating a it is a vertical coordinate system. Also if it is a CompoundCRS made of a VerticalCRS

Since

OGR 1.8.0

int IsCompound() const

Check if coordinate system is compound.

This method is the same as the C function OSRIsCompound().

Return

TRUE if this is rooted with a COMPD_CS node.

int IsSameGeogCS(const OGRSpatialReference *poOther) const

Do the GeogCS’es match?

This method is the same as the C function OSRIsSameGeogCS().

Return

TRUE if they are the same or FALSE otherwise.

Parameters
  • poOther: the SRS being compared against.

int IsSameGeogCS(const OGRSpatialReference *poOther, const char *const *papszOptions) const

Do the GeogCS’es match?

This method is the same as the C function OSRIsSameGeogCS().

Return

TRUE if they are the same or FALSE otherwise.

Parameters
  • poOther: the SRS being compared against.

  • papszOptions: options. ignored

int IsSameVertCS(const OGRSpatialReference *poOther) const

Do the VertCS’es match?

This method is the same as the C function OSRIsSameVertCS().

Return

TRUE if they are the same or FALSE otherwise.

Parameters
  • poOther: the SRS being compared against.

int IsSame(const OGRSpatialReference *poOtherSRS) const

Do these two spatial references describe the same system ?

Return

TRUE if equivalent or FALSE otherwise.

Parameters
  • poOtherSRS: the SRS being compared to.

int IsSame(const OGRSpatialReference *poOtherSRS, const char *const *papszOptions) const

Do these two spatial references describe the same system ?

This also takes into account the data axis to CRS axis mapping by default

Return

TRUE if equivalent or FALSE otherwise.

Parameters
  • poOtherSRS: the SRS being compared to.

  • papszOptions: options. NULL or NULL terminated list of options. Currently supported options are:

    • IGNORE_DATA_AXIS_TO_SRS_AXIS_MAPPING=YES/NO. Defaults to NO

    • CRITERION=STRICT/EQUIVALENT/EQUIVALENT_EXCEPT_AXIS_ORDER_GEOGCRS. Defaults to EQUIVALENT_EXCEPT_AXIS_ORDER_GEOGCRS.

void Clear()

Wipe current definition.

Returns OGRSpatialReference to a state with no definition, as it exists when first created. It does not affect reference counts.

OGRErr SetLocalCS(const char *pszName)

Set the user visible LOCAL_CS name.

This method is the same as the C function OSRSetLocalCS().

This method will ensure a LOCAL_CS node is created as the root, and set the provided name on it. It must be used before SetLinearUnits().

Return

OGRERR_NONE on success.

Parameters
  • pszName: the user visible name to assign. Not used as a key.

OGRErr SetProjCS(const char *pszName)

Set the user visible PROJCS name.

This method is the same as the C function OSRSetProjCS().

This method will ensure a PROJCS node is created as the root, and set the provided name on it. If used on a GEOGCS coordinate system, the GEOGCS node will be demoted to be a child of the new PROJCS root.

Return

OGRERR_NONE on success.

Parameters
  • pszName: the user visible name to assign. Not used as a key.

OGRErr SetProjection(const char *pszProjection)

Set a projection name.

This method is the same as the C function OSRSetProjection().

Return

OGRERR_NONE on success.

Parameters
  • pszProjection: the projection name, which should be selected from the macros in ogr_srs_api.h, such as SRS_PT_TRANSVERSE_MERCATOR.

OGRErr SetGeocCS(const char *pszGeocName)

Set the user visible GEOCCS name.

This method is the same as the C function OSRSetGeocCS().

This method will ensure a GEOCCS node is created as the root, and set the provided name on it. If used on a GEOGCS coordinate system, the DATUM and PRIMEM nodes from the GEOGCS will be transferred over to the GEOGCS.

Return

OGRERR_NONE on success.

Since

OGR 1.9.0

Parameters
  • pszName: the user visible name to assign. Not used as a key.

OGRErr SetGeogCS(const char *pszGeogName, const char *pszDatumName, const char *pszEllipsoidName, double dfSemiMajor, double dfInvFlattening, const char *pszPMName = nullptr, double dfPMOffset = 0.0, const char *pszUnits = nullptr, double dfConvertToRadians = 0.0)

Set geographic coordinate system.

This method is used to set the datum, ellipsoid, prime meridian and angular units for a geographic coordinate system. It can be used on its own to establish a geographic spatial reference, or applied to a projected coordinate system to establish the underlying geographic coordinate system.

This method does the same as the C function OSRSetGeogCS().

Return

OGRERR_NONE on success.

Parameters
  • pszGeogName: user visible name for the geographic coordinate system (not to serve as a key).

  • pszDatumName: key name for this datum. The OpenGIS specification lists some known values, and otherwise EPSG datum names with a standard transformation are considered legal keys.

  • pszSpheroidName: user visible spheroid name (not to serve as a key)

  • dfSemiMajor: the semi major axis of the spheroid.

  • dfInvFlattening: the inverse flattening for the spheroid. This can be computed from the semi minor axis as 1/f = 1.0 / (1.0 - semiminor/semimajor).

  • pszPMName: the name of the prime meridian (not to serve as a key) If this is NULL a default value of “Greenwich” will be used.

  • dfPMOffset: the longitude of Greenwich relative to this prime meridian. Always in Degrees

  • pszAngularUnits: the angular units name (see ogr_srs_api.h for some standard names). If NULL a value of “degrees” will be assumed.

  • dfConvertToRadians: value to multiply angular units by to transform them to radians. A value of SRS_UA_DEGREE_CONV will be used if pszAngularUnits is NULL.

OGRErr SetWellKnownGeogCS(const char *pszName)

Set a GeogCS based on well known name.

This may be called on an empty OGRSpatialReference to make a geographic coordinate system, or on something with an existing PROJCS node to set the underlying geographic coordinate system of a projected coordinate system.

The following well known text values are currently supported:

  • “WGS84”: same as “EPSG:4326” but has no dependence on EPSG data files.

  • “WGS72”: same as “EPSG:4322” but has no dependence on EPSG data files.

  • “NAD27”: same as “EPSG:4267” but has no dependence on EPSG data files.

  • “NAD83”: same as “EPSG:4269” but has no dependence on EPSG data files.

  • “EPSG:n”: where n is the code a Geographic coordinate reference system.

Return

OGRERR_NONE on success, or OGRERR_FAILURE if the name isn’t recognised, the target object is already initialized, or an EPSG value can’t be successfully looked up.

Parameters
  • pszName: name of well known geographic coordinate system.

OGRErr CopyGeogCSFrom(const OGRSpatialReference *poSrcSRS)

Copy GEOGCS from another OGRSpatialReference.

The GEOGCS information is copied into this OGRSpatialReference from another. If this object has a PROJCS root already, the GEOGCS is installed within it, otherwise it is installed as the root.

Return

OGRERR_NONE on success or an error code.

Parameters
  • poSrcSRS: the spatial reference to copy the GEOGCS information from.

OGRErr SetVertCS(const char *pszVertCSName, const char *pszVertDatumName, int nVertDatumClass = 2005)

Set the user visible VERT_CS name.

This method is the same as the C function OSRSetVertCS().

This method will ensure a VERT_CS node is created if needed. If the existing coordinate system is GEOGCS or PROJCS rooted, then it will be turned into a COMPD_CS.

Return

OGRERR_NONE on success.

Since

OGR 1.9.0

Parameters
  • pszVertCSName: the user visible name of the vertical coordinate system. Not used as a key.

  • pszVertDatumName: the user visible name of the vertical datum. It is helpful if this matches the EPSG name.

  • nVertDatumType: the OGC vertical datum type. Ignored

OGRErr SetCompoundCS(const char *pszName, const OGRSpatialReference *poHorizSRS, const OGRSpatialReference *poVertSRS)

Setup a compound coordinate system.

This method is the same as the C function OSRSetCompoundCS().

This method is replace the current SRS with a COMPD_CS coordinate system consisting of the passed in horizontal and vertical coordinate systems.

Return

OGRERR_NONE on success.

Parameters
  • pszName: the name of the compound coordinate system.

  • poHorizSRS: the horizontal SRS (PROJCS or GEOGCS).

  • poVertSRS: the vertical SRS (VERT_CS).

OGRErr PromoteTo3D(const char *pszName)

“Promotes” a 2D CRS to a 3D CRS one.

The new axis will be ellipsoidal height, oriented upwards, and with metre units.

Return

OGRERR_NONE if no error occurred.

Since

GDAL 3.1 and PROJ 6.3

Parameters
  • pszName: New name for the CRS. If set to NULL, the previous name will be used.

OGRErr SetFromUserInput(const char *pszDefinition)

Set spatial reference from various text formats.

This method will examine the provided input, and try to deduce the format, and then use it to initialize the spatial reference system. It may take the following forms:

  1. Well Known Text definition - passed on to importFromWkt().

  2. “EPSG:n” - number passed on to importFromEPSG().

  3. “EPSGA:n” - number passed on to importFromEPSGA().

  4. “AUTO:proj_id,unit_id,lon0,lat0” - WMS auto projections.

  5. “urn:ogc:def:crs:EPSG::n” - ogc urns

  6. PROJ.4 definitions - passed on to importFromProj4().

  7. filename - file read for WKT, XML or PROJ.4 definition.

  8. well known name accepted by SetWellKnownGeogCS(), such as NAD27, NAD83, WGS84 or WGS72.

  9. “IGNF:xxxx”, “ESRI:xxxx”, etc. from definitions from the PROJ database;

  10. PROJJSON (PROJ >= 6.2)

It is expected that this method will be extended in the future to support XML and perhaps a simplified “minilanguage” for indicating common UTM and State Plane definitions.

This method is intended to be flexible, but by its nature it is imprecise as it must guess information about the format intended. When possible applications should call the specific method appropriate if the input is known to be in a particular format.

This method does the same thing as the OSRSetFromUserInput() function.

Return

OGRERR_NONE on success, or an error code if the name isn’t recognised, the definition is corrupt, or an EPSG value can’t be successfully looked up.

Parameters
  • pszDefinition: text definition to try to deduce SRS from.

OGRErr SetTOWGS84(double dfDX, double dfDY, double dfDZ, double dfEX = 0.0, double dfEY = 0.0, double dfEZ = 0.0, double dfPPM = 0.0)

Set the Bursa-Wolf conversion to WGS84.

This will create the TOWGS84 node as a child of the DATUM. It will fail if there is no existing DATUM node. It will replace an existing TOWGS84 node if there is one.

The parameters have the same meaning as EPSG transformation 9606 (Position Vector 7-param. transformation).

This method is the same as the C function OSRSetTOWGS84().

Return

OGRERR_NONE on success.

Parameters
  • dfDX: X child in meters.

  • dfDY: Y child in meters.

  • dfDZ: Z child in meters.

  • dfEX: X rotation in arc seconds (optional, defaults to zero).

  • dfEY: Y rotation in arc seconds (optional, defaults to zero).

  • dfEZ: Z rotation in arc seconds (optional, defaults to zero).

  • dfPPM: scaling factor (parts per million).

OGRErr GetTOWGS84(double *padfCoef, int nCoeff = 7) const

Fetch TOWGS84 parameters, if available.

The parameters have the same meaning as EPSG transformation 9606 (Position Vector 7-param. transformation).

Return

OGRERR_NONE on success, or OGRERR_FAILURE if there is no TOWGS84 node available.

Parameters
  • padfCoeff: array into which up to 7 coefficients are placed.

  • nCoeffCount: size of padfCoeff - defaults to 7.

double GetSemiMajor(OGRErr *pnErr = nullptr) const

Get spheroid semi major axis (in metres starting with GDAL 3.0)

This method does the same thing as the C function OSRGetSemiMajor().

Return

semi-major axis, or SRS_WGS84_SEMIMAJOR if it can’t be found.

Parameters
  • pnErr: if non-NULL set to OGRERR_FAILURE if semi major axis can be found.

double GetSemiMinor(OGRErr *pnErr = nullptr) const

Get spheroid semi minor axis.

This method does the same thing as the C function OSRGetSemiMinor().

Return

semi-minor axis, or WGS84 semi minor if it can’t be found.

Parameters
  • pnErr: if non-NULL set to OGRERR_FAILURE if semi minor axis can be found.

double GetInvFlattening(OGRErr *pnErr = nullptr) const

Get spheroid inverse flattening.

This method does the same thing as the C function OSRGetInvFlattening().

Return

inverse flattening, or SRS_WGS84_INVFLATTENING if it can’t be found.

Parameters
  • pnErr: if non-NULL set to OGRERR_FAILURE if no inverse flattening can be found.

double GetEccentricity() const

Get spheroid eccentricity.

Return

eccentricity (or -1 in case of error)

Since

GDAL 2.3

double GetSquaredEccentricity() const

Get spheroid squared eccentricity.

Return

squared eccentricity (or -1 in case of error)

Since

GDAL 2.3

OGRErr SetAuthority(const char *pszTargetKey, const char *pszAuthority, int nCode)

Set the authority for a node.

This method is the same as the C function OSRSetAuthority().

Return

OGRERR_NONE on success.

Parameters
  • pszTargetKey: the partial or complete path to the node to set an authority on. i.e. “PROJCS”, “GEOGCS” or “GEOGCS|UNIT”.

  • pszAuthority: authority name, such as “EPSG”.

  • nCode: code for value with this authority.

OGRErr AutoIdentifyEPSG()

Set EPSG authority info if possible.

This method inspects a WKT definition, and adds EPSG authority nodes where an aspect of the coordinate system can be easily and safely corresponded with an EPSG identifier. In practice, this method will evolve over time. In theory it can add authority nodes for any object (i.e. spheroid, datum, GEOGCS, units, and PROJCS) that could have an authority node. Mostly this is useful to inserting appropriate PROJCS codes for common formulations (like UTM n WGS84).

If it success the OGRSpatialReference is updated in place, and the method return OGRERR_NONE. If the method fails to identify the general coordinate system OGRERR_UNSUPPORTED_SRS is returned but no error message is posted via CPLError().

This method is the same as the C function OSRAutoIdentifyEPSG().

Since GDAL 2.3, the FindMatches() method can also be used for improved matching by researching the EPSG catalog.

Return

OGRERR_NONE or OGRERR_UNSUPPORTED_SRS.

OGRSpatialReferenceH *FindMatches(char **papszOptions, int *pnEntries, int **ppanMatchConfidence) const

Try to identify a match between the passed SRS and a related SRS in a catalog (currently EPSG only)

Matching may be partial, or may fail. Returned entries will be sorted by decreasing match confidence (first entry has the highest match confidence).

The exact way matching is done may change in future versions.

The current algorithm is:

  • try first AutoIdentifyEPSG(). If it succeeds, return the corresponding SRS

  • otherwise iterate over all SRS from the EPSG catalog (as found in GDAL pcs.csv and gcs.csv files+esri_extra.wkt), and find those that match the input SRS using the IsSame() function (ignoring TOWGS84 clauses)

  • if there is a single match using IsSame() or one of the matches has the same SRS name, return it with 100% confidence

  • if a SRS has the same SRS name, but does not pass the IsSame() criteria, return it with 50% confidence.

  • otherwise return all candidate SRS that pass the IsSame() criteria with a 90% confidence.

A pre-built SRS cache in ~/.gdal/X.Y/srs_cache will be used if existing, otherwise it will be built at the first run of this function.

This method is the same as OSRFindMatches().

Return

an array of SRS that match the passed SRS, or NULL. Must be freed with OSRFreeSRSArray()

Since

GDAL 2.3

Parameters
  • papszOptions: NULL terminated list of options or NULL

  • pnEntries: Output parameter. Number of values in the returned array.

  • ppanMatchConfidence: Output parameter (or NULL). *ppanMatchConfidence will be allocated to an array of *pnEntries whose values between 0 and 100 indicate the confidence in the match. 100 is the highest confidence level. The array must be freed with CPLFree().

int GetEPSGGeogCS() const

Try to establish what the EPSG code for this coordinate systems GEOGCS might be.

Returns -1 if no reasonable guess can be made.

Return

EPSG code

const char *GetAuthorityCode(const char *pszTargetKey) const

Get the authority code for a node.

This method is used to query an AUTHORITY[] node from within the WKT tree, and fetch the code value.

While in theory values may be non-numeric, for the EPSG authority all code values should be integral.

This method is the same as the C function OSRGetAuthorityCode().

Return

value code from authority node, or NULL on failure. The value returned is internal and should not be freed or modified.

Parameters
  • pszTargetKey: the partial or complete path to the node to get an authority from. i.e. “PROJCS”, “GEOGCS”, “GEOGCS|UNIT” or NULL to search for an authority node on the root element.

const char *GetAuthorityName(const char *pszTargetKey) const

Get the authority name for a node.

This method is used to query an AUTHORITY[] node from within the WKT tree, and fetch the authority name value.

The most common authority is “EPSG”.

This method is the same as the C function OSRGetAuthorityName().

Return

value code from authority node, or NULL on failure. The value returned is internal and should not be freed or modified.

Parameters
  • pszTargetKey: the partial or complete path to the node to get an authority from. i.e. “PROJCS”, “GEOGCS”, “GEOGCS|UNIT” or NULL to search for an authority node on the root element.

bool GetAreaOfUse(double *pdfWestLongitudeDeg, double *pdfSouthLatitudeDeg, double *pdfEastLongitudeDeg, double *pdfNorthLatitudeDeg, const char **ppszAreaName) const

Return the area of use of the CRS.

This method is the same as the OSRGetAreaOfUse() function.

Return

true in case of success

Since

GDAL 3.0

Parameters
  • pdfWestLongitudeDeg: Pointer to a double to receive the western-most longitude, expressed in degree. Might be NULL. If the returned value is -1000, the bounding box is unknown.

  • pdfSouthLatitudeDeg: Pointer to a double to receive the southern-most latitude, expressed in degree. Might be NULL. If the returned value is -1000, the bounding box is unknown.

  • pdfEastLongitudeDeg: Pointer to a double to receive the eastern-most longitude, expressed in degree. Might be NULL. If the returned value is -1000, the bounding box is unknown.

  • pdfNorthLatitudeDeg: Pointer to a double to receive the northern-most latitude, expressed in degree. Might be NULL. If the returned value is -1000, the bounding box is unknown.

  • ppszAreaName: Pointer to a string to receive the name of the area of use. Might be NULL. Note that *ppszAreaName is short-lived and might be invalidated by further calls.

const char *GetExtension(const char *pszTargetKey, const char *pszName, const char *pszDefault = nullptr) const

Fetch extension value.

Fetch the value of the named EXTENSION item for the identified target node.

Return

node value if successful or pszDefault on failure.

Parameters
  • pszTargetKey: the name or path to the parent node of the EXTENSION.

  • pszName: the name of the extension being fetched.

  • pszDefault: the value to return if the extension is not found.

OGRErr SetExtension(const char *pszTargetKey, const char *pszName, const char *pszValue)

Set extension value.

Set the value of the named EXTENSION item for the identified target node.

Return

OGRERR_NONE on success

Parameters
  • pszTargetKey: the name or path to the parent node of the EXTENSION.

  • pszName: the name of the extension being fetched.

  • pszValue: the value to set

int FindProjParm(const char *pszParameter, const OGR_SRSNode *poPROJCS = nullptr) const

Return the child index of the named projection parameter on its parent PROJCS node.

Return

the child index of the named projection parameter. -1 on failure

Parameters
  • pszParameter: projection parameter to look for

  • poPROJCS: projection CS node to look in. If NULL is passed, the PROJCS node of the SpatialReference object will be searched.

OGRErr SetProjParm(const char *pszParmName, double dfValue)

Set a projection parameter value.

Adds a new PARAMETER under the PROJCS with the indicated name and value.

This method is the same as the C function OSRSetProjParm().

Please check http://www.remotesensing.org/geotiff/proj_list pages for legal parameter names for specific projections.

Return

OGRERR_NONE on success.

Parameters
  • pszParmName: the parameter name, which should be selected from the macros in ogr_srs_api.h, such as SRS_PP_CENTRAL_MERIDIAN.

  • dfValue: value to assign.

double GetProjParm(const char *pszName, double dfDefaultValue = 0.0, OGRErr *pnErr = nullptr) const

Fetch a projection parameter value.

NOTE: This code should be modified to translate non degree angles into degrees based on the GEOGCS unit. This has not yet been done.

This method is the same as the C function OSRGetProjParm().

Return

value of parameter.

Parameters
  • pszName: the name of the parameter to fetch, from the set of SRS_PP codes in ogr_srs_api.h.

  • dfDefaultValue: the value to return if this parameter doesn’t exist.

  • pnErr: place to put error code on failure. Ignored if NULL.

OGRErr SetNormProjParm(const char *pszName, double dfValue)

Set a projection parameter with a normalized value.

This method is the same as SetProjParm() except that the value of the parameter passed in is assumed to be in “normalized” form (decimal degrees for angular values, meters for linear values. The values are converted in a form suitable for the GEOGCS and linear units in effect.

This method is the same as the C function OSRSetNormProjParm().

Return

OGRERR_NONE on success.

Parameters
  • pszName: the parameter name, which should be selected from the macros in ogr_srs_api.h, such as SRS_PP_CENTRAL_MERIDIAN.

  • dfValue: value to assign.

double GetNormProjParm(const char *pszName, double dfDefaultValue = 0.0, OGRErr *pnErr = nullptr) const

Fetch a normalized projection parameter value.

This method is the same as GetProjParm() except that the value of the parameter is “normalized” into degrees or meters depending on whether it is linear or angular.

This method is the same as the C function OSRGetNormProjParm().

Return

value of parameter.

Parameters
  • pszName: the name of the parameter to fetch, from the set of SRS_PP codes in ogr_srs_api.h.

  • dfDefaultValue: the value to return if this parameter doesn’t exist.

  • pnErr: place to put error code on failure. Ignored if NULL.

OGRErr SetACEA(double dfStdP1, double dfStdP2, double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Albers Conic Equal Area.

OGRErr SetAE(double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Azimuthal Equidistant.

OGRErr SetBonne(double dfStdP1, double dfCentralMeridian, double dfFalseEasting, double dfFalseNorthing)

Bonne.

OGRErr SetCEA(double dfStdP1, double dfCentralMeridian, double dfFalseEasting, double dfFalseNorthing)

Cylindrical Equal Area.

OGRErr SetCS(double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Cassini-Soldner.

OGRErr SetEC(double dfStdP1, double dfStdP2, double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Equidistant Conic.

OGRErr SetEckert(int nVariation, double dfCentralMeridian, double dfFalseEasting, double dfFalseNorthing)

Eckert I.

OGRErr SetEckertIV(double dfCentralMeridian, double dfFalseEasting, double dfFalseNorthing)

Eckert IV.

OGRErr SetEckertVI(double dfCentralMeridian, double dfFalseEasting, double dfFalseNorthing)

Eckert VI.

OGRErr SetEquirectangular(double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Equirectangular.

OGRErr SetEquirectangular2(double dfCenterLat, double dfCenterLong, double dfPseudoStdParallel1, double dfFalseEasting, double dfFalseNorthing)

Equirectangular generalized form :

OGRErr SetGEOS(double dfCentralMeridian, double dfSatelliteHeight, double dfFalseEasting, double dfFalseNorthing)

Geostationary Satellite.

OGRErr SetGH(double dfCentralMeridian, double dfFalseEasting, double dfFalseNorthing)

Goode Homolosine.

OGRErr SetIGH()

Interrupted Goode Homolosine.

OGRErr SetGS(double dfCentralMeridian, double dfFalseEasting, double dfFalseNorthing)

Gall Stereograpic.

OGRErr SetGaussSchreiberTMercator(double dfCenterLat, double dfCenterLong, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Gauss Schreiber Transverse Mercator.

OGRErr SetGnomonic(double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Gnomonic.

OGRErr SetHOM(double dfCenterLat, double dfCenterLong, double dfAzimuth, double dfRectToSkew, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Hotine Oblique Mercator.

Set a Hotine Oblique Mercator projection using azimuth angle.

This projection corresponds to EPSG projection method 9812, also sometimes known as hotine oblique mercator (variant A)..

This method does the same thing as the C function OSRSetHOM().

Return

OGRERR_NONE on success.

Parameters
  • dfCenterLat: Latitude of the projection origin.

  • dfCenterLong: Longitude of the projection origin.

  • dfAzimuth: Azimuth, measured clockwise from North, of the projection centerline.

  • dfRectToSkew: Angle from Rectified to Skew Grid

  • dfScale: Scale factor applies to the projection origin.

  • dfFalseEasting: False easting.

  • dfFalseNorthing: False northing.

OGRErr SetHOM2PNO(double dfCenterLat, double dfLat1, double dfLong1, double dfLat2, double dfLong2, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Hotine Oblique Mercator 2 points.

Set a Hotine Oblique Mercator projection using two points on projection centerline.

This method does the same thing as the C function OSRSetHOM2PNO().

Return

OGRERR_NONE on success.

Parameters
  • dfCenterLat: Latitude of the projection origin.

  • dfLat1: Latitude of the first point on center line.

  • dfLong1: Longitude of the first point on center line.

  • dfLat2: Latitude of the second point on center line.

  • dfLong2: Longitude of the second point on center line.

  • dfScale: Scale factor applies to the projection origin.

  • dfFalseEasting: False easting.

  • dfFalseNorthing: False northing.

OGRErr SetHOMAC(double dfCenterLat, double dfCenterLong, double dfAzimuth, double dfRectToSkew, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Hotine Oblique Mercator Azimuth Center / Variant B.

Set an Hotine Oblique Mercator Azimuth Center projection using azimuth angle.

This projection corresponds to EPSG projection method 9815, also sometimes known as hotine oblique mercator (variant B).

This method does the same thing as the C function OSRSetHOMAC().

Return

OGRERR_NONE on success.

Parameters
  • dfCenterLat: Latitude of the projection origin.

  • dfCenterLong: Longitude of the projection origin.

  • dfAzimuth: Azimuth, measured clockwise from North, of the projection centerline.

  • dfRectToSkew: Angle from Rectified to Skew Grid

  • dfScale: Scale factor applies to the projection origin.

  • dfFalseEasting: False easting.

  • dfFalseNorthing: False northing.

OGRErr SetLOM(double dfCenterLat, double dfCenterLong, double dfAzimuth, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Laborde Oblique Mercator.

Set a Laborde Oblique Mercator projection.

Return

OGRERR_NONE on success.

Parameters
  • dfCenterLat: Latitude of the projection origin.

  • dfCenterLong: Longitude of the projection origin.

  • dfAzimuth: Azimuth, measured clockwise from North, of the projection centerline.

  • dfScale: Scale factor on the initiali line

  • dfFalseEasting: False easting.

  • dfFalseNorthing: False northing.

OGRErr SetIWMPolyconic(double dfLat1, double dfLat2, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

International Map of the World Polyconic.

OGRErr SetKrovak(double dfCenterLat, double dfCenterLong, double dfAzimuth, double dfPseudoStdParallelLat, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Krovak Oblique Conic Conformal.

Krovak east-north projection.

Note that dfAzimuth and dfPseudoStdParallel1 are ignored when exporting to PROJ and should be respectively set to 30.28813972222222 and 78.5

OGRErr SetLAEA(double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Lambert Azimuthal Equal-Area.

OGRErr SetLCC(double dfStdP1, double dfStdP2, double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Lambert Conformal Conic.

OGRErr SetLCC1SP(double dfCenterLat, double dfCenterLong, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Lambert Conformal Conic 1SP.

OGRErr SetLCCB(double dfStdP1, double dfStdP2, double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Lambert Conformal Conic (Belgium)

OGRErr SetMC(double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Miller Cylindrical.

OGRErr SetMercator(double dfCenterLat, double dfCenterLong, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Mercator 1SP.

OGRErr SetMercator2SP(double dfStdP1, double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Mercator 2SP.

OGRErr SetMollweide(double dfCentralMeridian, double dfFalseEasting, double dfFalseNorthing)

Mollweide.

OGRErr SetNZMG(double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

New Zealand Map Grid.

OGRErr SetOS(double dfOriginLat, double dfCMeridian, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Oblique Stereographic.

OGRErr SetOrthographic(double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Orthographic.

OGRErr SetPolyconic(double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Polyconic.

OGRErr SetPS(double dfCenterLat, double dfCenterLong, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Polar Stereographic.

OGRErr SetRobinson(double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Robinson.

OGRErr SetSinusoidal(double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Sinusoidal.

OGRErr SetStereographic(double dfCenterLat, double dfCenterLong, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Stereographic.

OGRErr SetSOC(double dfLatitudeOfOrigin, double dfCentralMeridian, double dfFalseEasting, double dfFalseNorthing)

Swiss Oblique Cylindrical.

OGRErr SetTM(double dfCenterLat, double dfCenterLong, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Transverse Mercator.

OGRErr SetTMVariant(const char *pszVariantName, double dfCenterLat, double dfCenterLong, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Transverse Mercator variants.

OGRErr SetTMG(double dfCenterLat, double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

Tunesia Mining Grid.

OGRErr SetTMSO(double dfCenterLat, double dfCenterLong, double dfScale, double dfFalseEasting, double dfFalseNorthing)

Transverse Mercator (South Oriented)

OGRErr SetTPED(double dfLat1, double dfLong1, double dfLat2, double dfLong2, double dfFalseEasting, double dfFalseNorthing)

Two Point Equidistant.

OGRErr SetVDG(double dfCenterLong, double dfFalseEasting, double dfFalseNorthing)

VanDerGrinten.

OGRErr SetUTM(int nZone, int bNorth = TRUE)

Universal Transverse Mercator.

Set UTM projection definition.

This will generate a projection definition with the full set of transverse mercator projection parameters for the given UTM zone. If no PROJCS[] description is set yet, one will be set to look like “UTM Zone %d, {Northern, Southern} Hemisphere”.

This method is the same as the C function OSRSetUTM().

Return

OGRERR_NONE on success.

Parameters
  • nZone: UTM zone.

  • bNorth: TRUE for northern hemisphere, or FALSE for southern hemisphere.

int GetUTMZone(int *pbNorth = nullptr) const

Get utm zone information.

This is the same as the C function OSRGetUTMZone().

In SWIG bindings (Python, Java, etc) the GetUTMZone() method returns a zone which is negative in the southern hemisphere instead of having the pbNorth flag used in the C and C++ interface.

Return

UTM zone number or zero if this isn’t a UTM definition.

Parameters
  • pbNorth: pointer to in to set to TRUE if northern hemisphere, or FALSE if southern.

OGRErr SetWagner(int nVariation, double dfCenterLat, double dfFalseEasting, double dfFalseNorthing)

Wagner I VII.

OGRErr SetQSC(double dfCenterLat, double dfCenterLong)

Quadrilateralized Spherical Cube.

OGRErr SetSCH(double dfPegLat, double dfPegLong, double dfPegHeading, double dfPegHgt)

Spherical, Cross-track, Height.

OGRErr SetVerticalPerspective(double dfTopoOriginLat, double dfTopoOriginLon, double dfTopoOriginHeight, double dfViewPointHeight, double dfFalseEasting, double dfFalseNorthing)

Vertical Perspective / Near-sided Perspective.

OGRErr SetDerivedGeogCRSWithPoleRotationGRIBConvention(const char *pszCRSName, double dfSouthPoleLat, double dfSouthPoleLon, double dfAxisRotation)

Pole rotation (GRIB convention)

OGRErr SetStatePlane(int nZone, int bNAD83 = TRUE, const char *pszOverrideUnitName = nullptr, double dfOverrideUnit = 0.0)

State Plane.

Set State Plane projection definition.

This will attempt to generate a complete definition of a state plane zone based on generating the entire SRS from the EPSG tables. If the EPSG tables are unavailable, it will produce a stubbed LOCAL_CS definition and return OGRERR_FAILURE.

This method is the same as the C function OSRSetStatePlaneWithUnits().

Return

OGRERR_NONE on success, or OGRERR_FAILURE on failure, mostly likely due to the EPSG tables not being accessible.

Parameters
  • nZone: State plane zone number, in the USGS numbering scheme (as distinct from the Arc/Info and Erdas numbering scheme.

  • bNAD83: TRUE if the NAD83 zone definition should be used or FALSE if the NAD27 zone definition should be used.

  • pszOverrideUnitName: Linear unit name to apply overriding the legal definition for this zone.

  • dfOverrideUnit: Linear unit conversion factor to apply overriding the legal definition for this zone.

OGRErr ImportFromESRIStatePlaneWKT(int nCode, const char *pszDatumName, const char *pszUnitsName, int nPCSCode, const char *pszCRSName = nullptr)

ImportFromESRIStatePlaneWKT.

OGRErr ImportFromESRIWisconsinWKT(const char *pszPrjName, double dfCentralMeridian, double dfLatOfOrigin, const char *pszUnitsName, const char *pszCRSName = nullptr)

ImportFromESRIWisconsinWKT.

Public Static Functions

void DestroySpatialReference(OGRSpatialReference *poSRS)

OGRSpatialReference destructor.

This static method will destroy a OGRSpatialReference. It is equivalent to calling delete on the object, but it ensures that the deallocation is properly executed within the OGR libraries heap on platforms where this can matter (win32).

This function is the same as OSRDestroySpatialReference()

Since

GDAL 1.7.0

Parameters
  • poSRS: the object to delete

int IsAngularParameter(const char *pszParameterName)

Is the passed projection parameter an angular one?

Return

TRUE or FALSE

int IsLongitudeParameter(const char *pszParameterName)

Is the passed projection parameter an angular longitude (relative to a prime meridian)?

Return

TRUE or FALSE

int IsLinearParameter(const char *pszParameterName)

Is the passed projection parameter an linear one measured in meters or some similar linear measure.

Return

TRUE or FALSE

OGRSpatialReference *GetWGS84SRS()

Returns an instance of a SRS object with WGS84 WKT.

Note: the instance will have SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER)

The reference counter of the returned object is not increased by this operation.

Return

instance.

Since

GDAL 2.0

static OGRSpatialReferenceH ToHandle(OGRSpatialReference *poSRS)

Convert a OGRSpatialReference* to a OGRSpatialReferenceH.

Since

GDAL 2.3

static OGRSpatialReference *FromHandle(OGRSpatialReferenceH hSRS)

Convert a OGRSpatialReferenceH to a OGRSpatialReference*.

Since

GDAL 2.3

Private Functions

void GetNormInfo() const

Set the internal information for normalizing linear, and angular values.

OGRErr importFromURNPart(const char *pszAuthority, const char *pszCode, const char *pszURN)

Private Members

std::unique_ptr<Private> d

Private Static Functions

CPLString lookupInDict(const char *pszDictFile, const char *pszCode)
class OGRCoordinateTransformation
#include <ogr_spatialref.h>

Interface for transforming between coordinate systems.

Currently, the only implementation within OGR is OGRProjCT, which requires the PROJ library.

Also, see OGRCreateCoordinateTransformation() for creating transformations.

Subclassed by AxisMappingCoordinateTransformation, CompositeCT, CutlineTransformer, GCPCoordTransformation

Public Functions

virtual ~OGRCoordinateTransformation()
virtual OGRSpatialReference *GetSourceCS() = 0

Fetch internal source coordinate system.

virtual OGRSpatialReference *GetTargetCS() = 0

Fetch internal target coordinate system.

virtual bool GetEmitErrors() const

Whether the transformer will emit CPLError.

virtual void SetEmitErrors(bool)

Set if the transformer must emit CPLError.

int Transform(int nCount, double *x, double *y, double *z = nullptr, int *pabSuccess = nullptr)

Transform points from source to destination space.

This method is the same as the C function OCTTransformEx().

Return

TRUE if some or all points transform successfully, or FALSE if if none transform.

Parameters
  • nCount: number of points to transform.

  • x: array of nCount X vertices, modified in place. Should not be NULL.

  • y: array of nCount Y vertices, modified in place. Should not be NULL.

  • z: array of nCount Z vertices, modified in place. Might be NULL.

  • pabSuccess: array of per-point flags set to TRUE if that point transforms, or FALSE if it does not. Might be NULL.

virtual int Transform(int nCount, double *x, double *y, double *z, double *t, int *pabSuccess) = 0

Transform points from source to destination space.

This method is the same as the C function OCTTransform4D().

Return

TRUE if some or all points transform successfully, or FALSE if if none transform.

Parameters
  • nCount: number of points to transform.

  • x: array of nCount X vertices, modified in place. Should not be NULL.

  • y: array of nCount Y vertices, modified in place. Should not be NULL.

  • z: array of nCount Z vertices, modified in place. Might be NULL.

  • t: array of nCount time values, modified in place. Might be NULL.

  • pabSuccess: array of per-point flags set to TRUE if that point transforms, or FALSE if it does not. Might be NULL.

Public Static Functions

void DestroyCT(OGRCoordinateTransformation *poCT)

OGRCoordinateTransformation destructor.

This function is the same as OGRCoordinateTransformation::~OGRCoordinateTransformation() and OCTDestroyCoordinateTransformation()

This static method will destroy a OGRCoordinateTransformation. It is equivalent to calling delete on the object, but it ensures that the deallocation is properly executed within the OGR libraries heap on platforms where this can matter (win32).

Since

GDAL 1.7.0

Parameters
  • poCT: the object to delete

static OGRCoordinateTransformationH ToHandle(OGRCoordinateTransformation *poCT)

Convert a OGRCoordinateTransformation* to a OGRCoordinateTransformationH.

Since

GDAL 2.3

static OGRCoordinateTransformation *FromHandle(OGRCoordinateTransformationH hCT)

Convert a OGRCoordinateTransformationH to a OGRCoordinateTransformation*.

Since

GDAL 2.3

struct OGRCoordinateTransformationOptions
#include <ogr_spatialref.h>

Context for coordinate transformation.

Since

GDAL 3.0

Public Functions

OGRCoordinateTransformationOptions()

Constructs a new OGRCoordinateTransformationOptions.

Since

GDAL 3.0

~OGRCoordinateTransformationOptions()

Destroys a OGRCoordinateTransformationOptions.

Since

GDAL 3.0

bool SetAreaOfInterest(double dfWestLongitudeDeg, double dfSouthLatitudeDeg, double dfEastLongitudeDeg, double dfNorthLatitudeDeg)

Sets an area of interest.

The west longitude is generally lower than the east longitude, except for areas of interest that go across the anti-meridian.

Return

true in case of success.

Since

GDAL 3.0

Parameters
  • dfWestLongitudeDeg: West longitude (in degree). Must be in [-180,180]

  • dfSouthLatitudeDeg: South latitude (in degree). Must be in [-90,90]

  • dfEastLongitudeDeg: East longitude (in degree). Must be in [-180,180]

  • dfNorthLatitudeDeg: North latitude (in degree). Must be in [-90,90]

bool SetCoordinateOperation(const char *pszCT, bool bReverseCT)

Sets a coordinate operation.

This is a user override to be used instead of the normally computed pipeline.

The pipeline must take into account the axis order of the source and target SRS.

The pipeline may be provided as a PROJ string (single step operation or multiple step string starting with +proj=pipeline), a WKT2 string describing a CoordinateOperation, or a “urn:ogc:def:coordinateOperation:EPSG::XXXX” URN

Return

true in case of success.

Since

GDAL 3.0

Parameters
  • pszCO: PROJ or WKT string describing a coordinate operation

  • bReverseCO: Whether the PROJ or WKT string should be evaluated in the reverse path