Data types¶

This section describes the numerous data types in use in PROJ.4. As a rule of thumb PROJ.4 data types are prefixed with PJ_, or in one particular case, is simply called PJ. A few notable exceptions can be traced back to the very early days of PROJ.4 when the PJ_ prefix was not consistently used.

Transformation objects¶

type PJ¶: Object containing everything related to a given projection or transformation. As a user of the PROJ.4 library you are only exposed to pointers to this object and the contents is hidden behind the public API. PJ objects are created with proj_create() and destroyed with proj_destroy().

type PJ_DIRECTION¶

Enumeration that is used to convey in which direction a given transformation should be performed. Used in transformation function call as described in the section on transformation functions.

Forward transformations are defined with the :c:

typedef enum proj_direction {
    PJ_FWD   =  1,   /* Forward    */
    PJ_IDENT =  0,   /* Do nothing */
    PJ_INV   = -1    /* Inverse    */
} PJ_DIRECTION;

enumerator PJ_FWD¶: Perform transformation in the forward direction.

enumerator PJ_IDENT¶: Identity. Do nothing.

enumerator PJ_INV¶: Perform transformation in the inverse direction.

type PJ_CONTEXT¶: Context objects enable safe multi-threaded usage of PROJ.4. Each PJ object is connected to a context (if not specified, the default context is used). All operations within a context should be performed in the same thread. PJ_CONTEXT objects are created with proj_context_create() and destroyed with proj_context_destroy().

type PJ_AREA¶

New in version 6.0.0.

Opaque object describing an area in which a transformation is performed.

It is used with proj_create_crs_to_crs() to select the best transformation between the two input coordinate reference systems.

2 dimensional coordinates¶

Various 2-dimensional coordinate data types.

type PJ_LP¶

Geodetic coordinate, latitude and longitude. Usually in radians.

typedef struct { double lam, phi; } PJ_LP;

double PJ_LP.lam¶: Longitude. Lambda.

double PJ_LP.phi¶: Latitude. Phi.

type PJ_XY¶

2-dimensional cartesian coordinate.

typedef struct { double x, y; } PJ_XY;

double PJ_XY.x¶: Easting.

double PJ_XY.y¶: Northing.

type PJ_UV¶

2-dimensional generic coordinate. Usually used when contents can be either a PJ_XY or PJ_LP.

typedef struct {double u, v; } PJ_UV;

double PJ_UV.u¶: Longitude or easting, depending on use.

double PJ_UV.v¶: Latitude or northing, depending on use.

3 dimensional coordinates¶

The following data types are the 3-dimensional equivalents to the data types above.

type PJ_LPZ¶

3-dimensional version of PJ_LP. Holds longitude, latitude and a vertical component.

typedef struct { double lam, phi, z; } PJ_LPZ;

double PJ_LPZ.lam¶: Longitude. Lambda.

double PJ_LPZ.phi¶: Latitude. Phi.

double PJ_LPZ.z¶: Vertical component.

type PJ_XYZ¶

Cartesian coordinate in 3 dimensions. Extension of PJ_XY.

typedef struct { double x, y, z; } PJ_XYZ;

double PJ_XYZ.x¶: Easting or the X component of a 3D cartesian system.

double PJ_XYZ.y¶: Northing or the Y component of a 3D cartesian system.

double PJ_XYZ.z¶: Vertical component or the Z component of a 3D cartesian system.

type PJ_UVW¶

3-dimensional extension of PJ_UV.

typedef struct {double u, v, w; } PJ_UVW;

double PJ_UVW.u¶: Longitude or easting, depending on use.

double PJ_UVW.v¶: Latitude or northing, depending on use.

double PJ_UVW.w¶: Vertical component.

Spatiotemporal coordinate types¶

The following data types are extensions of the triplets above into the time domain.

type PJ_LPZT¶

Spatiotemporal version of PJ_LPZ.

typedef struct {
    double lam;
    double phi;
    double z;
    double t;
} PJ_LPZT;

double PJ_LPZT.lam¶: Longitude.

double PJ_LPZT.phi¶: Latitude

double PJ_LPZT.z¶: Vertical component.

double PJ_LPZT.t¶: Time component.

type PJ_XYZT¶

Generic spatiotemporal coordinate. Useful for e.g. cartesian coordinates with an attached time-stamp.

typedef struct {
    double x;
    double y;
    double z;
    double t;
} PJ_XYZT;

double PJ_XYZT.x¶: Easting or the X component of a 3D cartesian system.

double PJ_XYZT.y¶: Northing or the Y component of a 3D cartesian system.

double PJ_XYZT.z¶: Vertical or the Z component of a 3D cartesian system.

double PJ_XYZT.t¶: Time component.

type PJ_UVWT¶

Spatiotemporal version of PJ_UVW.

typedef struct { double u, v, w, t; } PJ_UVWT;

double PJ_UVWT.e¶: First horizontal component.

double PJ_UVWT.n¶: Second horizontal component.

double PJ_UVWT.w¶: Vertical component.

double PJ_UVWT.t¶: Temporal component.

Ancillary types for geodetic computations¶

type PJ_OPK¶

Rotations, for instance three euler angles.

typedef struct { double o, p, k; } PJ_OPK;

double PJ_OPK.o¶: First rotation angle, omega.

double PJ_OPK.p¶: Second rotation angle, phi.

double PJ_OPK.k¶: Third rotation angle, kappa.

type PJ_ENU¶

East, north and up components.

typedef struct { double e, n, u; }          PJ_ENU;

double PJ_ENU.e¶: East component.

double PJ_ENU.n¶: North component.

double PJ_ENU.u¶: Up component.

type PJ_GEOD¶

Geodesic length, forward and reverse azimuths.

typedef struct { double s, a1, a2; }        PJ_GEOD;

double PJ_GEOD.s¶: Geodesic length.

double PJ_GEOD.a1¶: Forward azimuth.

double PJ_GEOD.a2¶: Reverse azimuth.

Complex coordinate types¶

type PJ_COORD¶

General purpose coordinate union type, applicable in two, three and four dimensions. This is the default coordinate datatype used in PROJ.

typedef union {
    double v[4];
    PJ_XYZT xyzt;
    PJ_UVWT uvwt;
    PJ_LPZT lpzt;
    PJ_GEOD geod;
    PJ_OPK opk;
    PJ_ENU enu;
    PJ_XYZ  xyz;
    PJ_UVW  uvw;
    PJ_LPZ  lpz;
    PJ_XY   xy;
    PJ_UV   uv;
    PJ_LP   lp;
} PJ_COORD ;

double v[4]¶: Generic four-dimensional vector.

PJ_XYZT PJ_COORD.xyzt¶: Spatiotemporal cartesian coordinate.

PJ_UVWT PJ_COORD.uvwt¶: Spatiotemporal generic coordinate.

PJ_LPZT PJ_COORD.lpzt¶: Longitude, latitude, vertical and time components.

PJ_GEOD PJ_COORD.geod¶: Geodesic length, forward and reverse azimuths.

PJ_OPK PJ_COORD.opk¶: Rotations, for instance three euler angles.

PJ_ENU PJ_COORD.enu¶: East, north and up components.

PJ_XYZ PJ_COORD.xyz¶: 3-dimensional cartesian coordinate.

PJ_UVW PJ_COORD.uvw¶: 3-dimensional generic coordinate.

PJ_LPZ PJ_COORD.lpz¶: Longitude, latitude and vertical component.

PJ_XY PJ_COORD.xy¶: 2-dimensional cartesian coordinate.

PJ_UV PJ_COORD.uv¶: 2-dimensional generic coordinate.

PJ_LP PJ_COORD.lp¶: Longitude and latitude.

Projection derivatives¶

type PJ_FACTORS¶

Various cartographic properties, such as scale factors, angular distortion and meridian convergence. Calculated with proj_factors().

typedef struct {
    double meridional_scale;
    double parallel_scale;
    double areal_scale;

    double angular_distortion;
    double meridian_parallel_angle;
    double meridian_convergence;

    double tissot_semimajor;
    double tissot_semiminor;

    double dx_dlam;
    double dx_dphi;
    double dy_dlam;
    double dy_dphi;
} PJ_FACTORS;

double PJ_FACTORS.meridional_scale¶: Meridional scale at coordinate \(\left(\lambda,\phi\right)\).

double PJ_FACTORS.parallel_scale¶: Parallel scale at coordinate \(\left(\lambda,\phi\right)\).

double PJ_FACTORS.areal_scale¶: Areal scale factor at coordinate \(\left(\lambda,\phi\right)\).

double PJ_FACTORS.angular_distortion¶: Angular distortion at coordinate \(\left(\lambda,\phi\right)\).

double PJ_FACTORS.meridian_parallel_angle¶

Meridian/parallel angle, \(\theta^\prime\), at coordinate \(\left(\lambda,\phi\right)\).

double PJ_FACTORS.meridian_convergence¶: Meridian convergence at coordinate \(\left(\lambda,\phi\right)\). Sometimes also described as grid declination.

double PJ_FACTORS.tissot_semimajor¶: Maximum scale factor.

double PJ_FACTORS.tissot_semiminor¶: Minimum scale factor.

double PJ_FACTORS.dx_dlam¶: Partial derivative \(\frac{\partial x}{\partial \lambda}\) of coordinate \(\left(\lambda,\phi\right)\).

double PJ_FACTORS.dy_dlam¶: Partial derivative \(\frac{\partial y}{\partial \lambda}\) of coordinate \(\left(\lambda,\phi\right)\).

double PJ_FACTORS.dx_dphi¶: Partial derivative \(\frac{\partial x}{\partial \phi}\) of coordinate \(\left(\lambda,\phi\right)\).

double PJ_FACTORS.dy_dphi¶: Partial derivative \(\frac{\partial y}{\partial \phi}\) of coordinate \(\left(\lambda,\phi\right)\).

List structures¶

type PJ_OPERATIONS¶

Description a PROJ.4 operation

struct PJ_OPERATIONS {
    const char  *id;            /* operation keyword */
    PJ *(*proj)(PJ *);          /* operation  entry point */
    char    * const *descr;     /* description text */
};

const char *id¶: Operation keyword.

PJ *(*op)(PJ*)¶: Operation entry point.

char *const *descr¶: Description of operation.

type PJ_ELLPS¶

Description of ellipsoids defined in PROJ.4

struct PJ_ELLPS {
    const char  *id;
    const char  *major;
    const char  *ell;
    const char  *name;
};

const char *id¶: Keyword name of the ellipsoid.

const char *major¶: Semi-major axis of the ellipsoid, or radius in case of a sphere.

const char *ell¶: Elliptical parameter, e.g. rf=298.257 or b=6356772.2.

const char *name¶: Name of the ellipsoid

type PJ_UNITS¶

Distance units defined in PROJ.

struct PJ_UNITS {
    const char  *id;        /* units keyword */
    const char  *to_meter;  /* multiply by value to get meters */
    const char  *name;      /* comments */
    double      factor;     /* to_meter factor in actual numbers */
};

const char *id¶: Keyword for the unit.

const char *to_meter¶: Text representation of the factor that converts a given unit to meters

const char *name¶: Name of the unit.

double factor¶: Conversion factor that converts the unit to meters.

type PJ_PRIME_MERIDIANS¶

Prime meridians defined in PROJ.

struct PJ_PRIME_MERIDIANS {
    const char  *id;
    const char  *defn;
};

const char *id¶: Keyword for the prime meridian

const char *def¶: Offset from Greenwich in DMS format.

Info structures¶

type PJ_INFO¶

Struct holding information about the current instance of PROJ. Struct is populated by proj_info().

typedef struct {
    int           major;
    int           minor;
    int           patch;
    const char   *release;
    const char   *version;
    const char   *searchpath;
} PJ_INFO;

const char *PJ_INFO.release¶: Release info. Version number and release date, e.g. “Rel. 4.9.3, 15 August 2016”.

const char *PJ_INFO.version¶: Text representation of the full version number, e.g. “4.9.3”.

int PJ_INFO.major¶: Major version number.

int PJ_INFO.minor¶: Minor version number.

int PJ_INFO.patch¶: Patch level of release.

const char PJ_INFO.searchpath¶: Search path for PROJ. List of directories separated by semicolons (Windows) or colons (non-Windows), e.g. C:\\Users\\doctorwho;C:\\OSGeo4W64\\share\\proj. Grids and init files are looked for in directories in the search path.

type PJ_PROJ_INFO¶

Struct holding information about a PJ object. Populated by proj_pj_info(). The PJ_PROJ_INFO object provides a view into the internals of a PJ, so once the PJ is destroyed or otherwise becomes invalid, so does the PJ_PROJ_INFO

typedef struct {
    const char  *id;
    const char  *description;
    const char  *definition;
    int          has_inverse;
    double       accuracy;
} PJ_PROJ_INFO;

const char *PJ_PROJ_INFO.id¶: Short ID of the operation the PJ object is based on, that is, what comes after the +proj= in a proj-string, e.g. “merc”.

const char *PJ_PROJ_INFO.description¶: Long describes of the operation the PJ object is based on, e.g. “Mercator Cyl, Sph&Ell lat_ts=”.

const char *PJ_PROJ_INFO.definition¶: The proj-string that was used to create the PJ object with, e.g. “+proj=merc +lat_0=24 +lon_0=53 +ellps=WGS84”.

int PJ_PROJ_INFO.has_inverse¶: 1 if an inverse mapping of the defined operation exists, otherwise 0.

double PJ_PROJ_INFO.accuracy¶: Expected accuracy of the transformation. -1 if unknown.

type PJ_GRID_INFO¶

Struct holding information about a specific grid in the search path of PROJ. Populated with the function proj_grid_info().

typedef struct {
    char        gridname[32];
    char        filename[260];
    char        format[8];
    LP          lowerleft;
    LP          upperright;
    int         n_lon, n_lat;
    double      cs_lon, cs_lat;
} PJ_GRID_INFO;

char PJ_GRID_INFO.gridname[32]¶: Name of grid, e.g. “BETA2007.gsb”.

char PJ_GRID_INFO¶: Full path of grid file, e.g. “C:\OSGeo4W64\share\proj\BETA2007.gsb”

char PJ_GRID_INFO.format[8]¶: File format of grid file, e.g. “ntv2”

LP PJ_GRID_INFO.lowerleft¶: Geodetic coordinate of lower left corner of grid.

LP PJ_GRID_INFO.upperright¶: Geodetic coordinate of upper right corner of grid.

int PJ_GRID_INFO.n_lon¶: Number of grid cells in the longitudinal direction.

int PJ_GRID_INFO.n_lat¶: Number of grid cells in the latitudinal direction.

double PJ_GRID_INFO.cs_lon¶: Cell size in the longitudinal direction. In radians.

double PJ_GRID_INFO.cs_lat¶: Cell size in the latitudinal direction. In radians.

type PJ_INIT_INFO¶

Struct holding information about a specific init file in the search path of PROJ. Populated with the function proj_init_info().

typedef struct {
    char        name[32];
    char        filename[260];
    char        version[32];
    char        origin[32];
    char        lastupdate[16];
} PJ_INIT_INFO;

char PJ_INIT_INFO.name[32]¶: Name of init file, e.g. “epsg”.

char PJ_INIT_INFO.filename[260]¶: Full path of init file, e.g. “C:\OSGeo4W64\share\proj\epsg”

char PJ_INIT_INFO.version[32]¶: Version number of init file, e.g. “9.0.0”

char PJ_INIT_INFO.origin[32]¶: Originating entity of the init file, e.g. “EPSG”

char PJ_INIT_INFO.lastupdate¶: Date of last update of the init file.

Error codes¶

New in version 8.0.0.

Three classes of errors are defined below. The belonging of a given error code to a class can bit tested with a binary and test. The error class itself can be used as an error value in some rare cases where the error does not fit into a more precise error value.

Those error codes are still quite generic for a number of them. Details on the actual errors will be typically logged with the PJ_LOG_ERROR level.

Errors in class PROJ_ERR_INVALID_OP¶

PROJ_ERR_INVALID_OP¶: Class of error codes typically related to coordinate operation initialization, typically when creating a PJ* object from a PROJ string.

Note

some of them can also be emitted during coordinate transformation, like PROJ_ERR_INVALID_OP_FILE_NOT_FOUND_OR_INVALID in case the resource loading is deferred until it is really needed.

PROJ_ERR_INVALID_OP_WRONG_SYNTAX¶: Invalid pipeline structure, missing +proj argument, etc.

PROJ_ERR_INVALID_OP_MISSING_ARG¶: Missing required operation parameter

PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE¶: One of the operation parameter has an illegal value.

PROJ_ERR_INVALID_OP_MUTUALLY_EXCLUSIVE_ARGS¶: Mutually exclusive arguments

PROJ_ERR_INVALID_OP_FILE_NOT_FOUND_OR_INVALID¶: File not found or with invalid content (particular case of PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE)

Errors in class PROJ_ERR_COORD_TRANSFM¶

PROJ_ERR_COORD_TRANSFM¶: Class of error codes related to transformation on a specific coordinate.

PROJ_ERR_COORD_TRANSFM_INVALID_COORD¶: Invalid input coordinate. e.g. a latitude > 90°.

PROJ_ERR_COORD_TRANSFM_OUTSIDE_PROJECTION_DOMAIN¶: Coordinate is outside of the projection domain. e.g. approximate mercator with |longitude - lon_0| > 90°, or iterative convergence method failed.

PROJ_ERR_COORD_TRANSFM_NO_OPERATION¶: No operation found, e.g. if no match the required accuracy, or if ballpark transformations were asked to not be used and they would be only such candidate.

PROJ_ERR_COORD_TRANSFM_OUTSIDE_GRID¶: Point to transform falls outside grid/subgrid/TIN.

PROJ_ERR_COORD_TRANSFM_GRID_AT_NODATA¶: Point to transform falls in a grid cell that evaluates to nodata.

Errors in class PROJ_ERR_OTHER¶

PROJ_ERR_OTHER¶: Class of error codes that do not fit into one of the above class.

PROJ_ERR_OTHER_API_MISUSE¶: Error related to a misuse of PROJ API.

PROJ_ERR_OTHER_NO_INVERSE_OP¶: No inverse method available

PROJ_ERR_OTHER_NETWORK_ERROR¶: Failure when accessing a network resource.

Logging¶

type PJ_LOG_LEVEL¶

Enum of logging levels in PROJ. Used to set the logging level in PROJ. Usually using proj_log_level().

enumerator PJ_LOG_NONE¶: Don’t log anything.

enumerator PJ_LOG_ERROR¶: Log only errors.

enumerator PJ_LOG_DEBUG¶: Log errors and additional debug information.

enumerator PJ_LOG_TRACE¶: Highest logging level. Log everything including very detailed debug information.

enumerator PJ_LOG_TELL¶: Special logging level that when used in proj_log_level() will return the current logging level set in PROJ.

New in version 5.1.0.

type PJ_LOG_FUNC¶

Function prototype for the logging function used by PROJ. Defined as

typedef void (*PJ_LOG_FUNCTION)(void *, int, const char *);

where the first argument (void pointer) references a data structure used by the calling application, the second argument (int type) is used to set the logging level and the third argument (const char pointer) is the string that will be logged by the function.

New in version 5.1.0.

Setting custom I/O functions¶

New in version 7.0.0.

struct PROJ_FILE_API¶

File API callbacks

Public Members

int version¶: Version of this structure. Should be set to 1 currently.

PROJ_FILE_HANDLE *(*open_cbk)(PJ_CONTEXT *ctx, const char *filename, PROJ_OPEN_ACCESS access, void *user_data)¶: Open file. Return NULL if error

size_t (*read_cbk)(PJ_CONTEXT *ctx, PROJ_FILE_HANDLE*, void *buffer, size_t sizeBytes, void *user_data)¶: Read sizeBytes into buffer from current position and return number of bytes read

size_t (*write_cbk)(PJ_CONTEXT *ctx, PROJ_FILE_HANDLE*, const void *buffer, size_t sizeBytes, void *user_data)¶: Write sizeBytes into buffer from current position and return number of bytes written

int (*seek_cbk)(PJ_CONTEXT *ctx, PROJ_FILE_HANDLE*, long long offset, int whence, void *user_data)¶: Seek to offset using whence=SEEK_SET/SEEK_CUR/SEEK_END. Return TRUE in case of success

unsigned long long (*tell_cbk)(PJ_CONTEXT *ctx, PROJ_FILE_HANDLE*, void *user_data)¶: Return current file position

void (*close_cbk)(PJ_CONTEXT *ctx, PROJ_FILE_HANDLE*, void *user_data)¶: Close file

int (*exists_cbk)(PJ_CONTEXT *ctx, const char *filename, void *user_data)¶: Return TRUE if a file exists

int (*mkdir_cbk)(PJ_CONTEXT *ctx, const char *filename, void *user_data)¶: Return TRUE if directory exists or could be created

int (*unlink_cbk)(PJ_CONTEXT *ctx, const char *filename, void *user_data)¶: Return TRUE if file could be removed

int (*rename_cbk)(PJ_CONTEXT *ctx, const char *oldPath, const char *newPath, void *user_data)¶: Return TRUE if file could be renamed

typedef struct PROJ_FILE_HANDLE PROJ_FILE_HANDLE¶: Opaque structure for PROJ for a file handle. Implementations might cast it to their structure/class of choice.

enum PROJ_OPEN_ACCESS¶

Open access / mode

Values:

enumerator PROJ_OPEN_ACCESS_READ_ONLY¶: Read-only access. Equivalent to “rb”

enumerator PROJ_OPEN_ACCESS_READ_UPDATE¶: Read-update access. File should be created if not existing. Equivalent to “r+b”

enumerator PROJ_OPEN_ACCESS_CREATE¶: Create access. File should be truncated to 0-byte if already existing. Equivalent to “w+b”

C API for ISO-19111 functionality¶

enum PJ_GUESSED_WKT_DIALECT¶

Guessed WKT “dialect”.

Values:

enumerator PJ_GUESSED_WKT2_2019¶: WKT2:2019

enumerator PJ_GUESSED_WKT2_2018¶: Deprecated alias for PJ_GUESSED_WKT2_2019

enumerator PJ_GUESSED_WKT2_2015¶: WKT2:2015

enumerator PJ_GUESSED_WKT1_GDAL¶: WKT1 specification

enumerator PJ_GUESSED_WKT1_ESRI¶: ESRI variant of WKT1

enumerator PJ_GUESSED_NOT_WKT¶: Not WKT / unrecognized

enum PJ_CATEGORY¶

Object category.

Values:

enumerator PJ_CATEGORY_ELLIPSOID¶

enumerator PJ_CATEGORY_PRIME_MERIDIAN¶

enumerator PJ_CATEGORY_DATUM¶

enumerator PJ_CATEGORY_CRS¶

enumerator PJ_CATEGORY_COORDINATE_OPERATION¶

enumerator PJ_CATEGORY_DATUM_ENSEMBLE¶

enum PJ_TYPE¶

Object type.

Values:

enumerator PJ_TYPE_UNKNOWN¶

enumerator PJ_TYPE_ELLIPSOID¶

enumerator PJ_TYPE_PRIME_MERIDIAN¶

enumerator PJ_TYPE_GEODETIC_REFERENCE_FRAME¶

enumerator PJ_TYPE_DYNAMIC_GEODETIC_REFERENCE_FRAME¶

enumerator PJ_TYPE_VERTICAL_REFERENCE_FRAME¶

enumerator PJ_TYPE_DYNAMIC_VERTICAL_REFERENCE_FRAME¶

enumerator PJ_TYPE_DATUM_ENSEMBLE¶

enumerator PJ_TYPE_CRS¶: Abstract type, not returned by proj_get_type()

enumerator PJ_TYPE_GEODETIC_CRS¶

enumerator PJ_TYPE_GEOCENTRIC_CRS¶

enumerator PJ_TYPE_GEOGRAPHIC_CRS¶: proj_get_type() will never return that type, but PJ_TYPE_GEOGRAPHIC_2D_CRS or PJ_TYPE_GEOGRAPHIC_3D_CRS.

enumerator PJ_TYPE_GEOGRAPHIC_2D_CRS¶

enumerator PJ_TYPE_GEOGRAPHIC_3D_CRS¶

enumerator PJ_TYPE_VERTICAL_CRS¶

enumerator PJ_TYPE_PROJECTED_CRS¶

enumerator PJ_TYPE_COMPOUND_CRS¶

enumerator PJ_TYPE_TEMPORAL_CRS¶

enumerator PJ_TYPE_ENGINEERING_CRS¶

enumerator PJ_TYPE_BOUND_CRS¶

enumerator PJ_TYPE_OTHER_CRS¶

enumerator PJ_TYPE_CONVERSION¶

enumerator PJ_TYPE_TRANSFORMATION¶

enumerator PJ_TYPE_CONCATENATED_OPERATION¶

enumerator PJ_TYPE_OTHER_COORDINATE_OPERATION¶

enumerator PJ_TYPE_TEMPORAL_DATUM¶

enumerator PJ_TYPE_ENGINEERING_DATUM¶

enumerator PJ_TYPE_PARAMETRIC_DATUM¶

enum PJ_COMPARISON_CRITERION¶

Comparison criterion.

Values:

enumerator PJ_COMP_STRICT¶: All properties are identical.

enumerator PJ_COMP_EQUIVALENT¶: The objects are equivalent for the purpose of coordinate operations. They can differ by the name of their objects, identifiers, other metadata. Parameters may be expressed in different units, provided that the value is (with some tolerance) the same once expressed in a common unit.

enumerator PJ_COMP_EQUIVALENT_EXCEPT_AXIS_ORDER_GEOGCRS¶: Same as EQUIVALENT, relaxed with an exception that the axis order of the base CRS of a DerivedCRS/ProjectedCRS or the axis order of a GeographicCRS is ignored. Only to be used with DerivedCRS/ProjectedCRS/GeographicCRS

enum PJ_WKT_TYPE¶

WKT version.

Values:

enumerator PJ_WKT2_2015¶: cf osgeo::proj::io::WKTFormatter::Convention::WKT2

enumerator PJ_WKT2_2015_SIMPLIFIED¶: cf osgeo::proj::io::WKTFormatter::Convention::WKT2_SIMPLIFIED

enumerator PJ_WKT2_2019¶: cf osgeo::proj::io::WKTFormatter::Convention::WKT2_2019

enumerator PJ_WKT2_2018¶: Deprecated alias for PJ_WKT2_2019

enumerator PJ_WKT2_2019_SIMPLIFIED¶: cf osgeo::proj::io::WKTFormatter::Convention::WKT2_2019_SIMPLIFIED

enumerator PJ_WKT2_2018_SIMPLIFIED¶: Deprecated alias for PJ_WKT2_2019

enumerator PJ_WKT1_GDAL¶: cf osgeo::proj::io::WKTFormatter::Convention::WKT1_GDAL

enumerator PJ_WKT1_ESRI¶: cf osgeo::proj::io::WKTFormatter::Convention::WKT1_ESRI

enum PROJ_CRS_EXTENT_USE¶

Specify how source and target CRS extent should be used to restrict candidate operations (only taken into account if no explicit area of interest is specified.

Values:

enumerator PJ_CRS_EXTENT_NONE¶: Ignore CRS extent

enumerator PJ_CRS_EXTENT_BOTH¶: Test coordinate operation extent against both CRS extent.

enumerator PJ_CRS_EXTENT_INTERSECTION¶: Test coordinate operation extent against the intersection of both CRS extent.

enumerator PJ_CRS_EXTENT_SMALLEST¶: Test coordinate operation against the smallest of both CRS extent.

enum PROJ_GRID_AVAILABILITY_USE¶

Describe how grid availability is used.

Values:

enumerator PROJ_GRID_AVAILABILITY_USED_FOR_SORTING¶: Grid availability is only used for sorting results. Operations where some grids are missing will be sorted last.

enumerator PROJ_GRID_AVAILABILITY_DISCARD_OPERATION_IF_MISSING_GRID¶: Completely discard an operation if a required grid is missing.

enumerator PROJ_GRID_AVAILABILITY_IGNORED¶: Ignore grid availability at all. Results will be presented as if all grids were available.

enumerator PROJ_GRID_AVAILABILITY_KNOWN_AVAILABLE¶: Results will be presented as if grids known to PROJ (that is registered in the grid_alternatives table of its database) were available. Used typically when networking is enabled.

enum PJ_PROJ_STRING_TYPE¶

PROJ string version.

Values:

enumerator PJ_PROJ_5¶: cf osgeo::proj::io::PROJStringFormatter::Convention::PROJ_5

enumerator PJ_PROJ_4¶: cf osgeo::proj::io::PROJStringFormatter::Convention::PROJ_4

enum PROJ_SPATIAL_CRITERION¶

Spatial criterion to restrict candidate operations.

Values:

enumerator PROJ_SPATIAL_CRITERION_STRICT_CONTAINMENT¶: The area of validity of transforms should strictly contain the are of interest.

enumerator PROJ_SPATIAL_CRITERION_PARTIAL_INTERSECTION¶: The area of validity of transforms should at least intersect the area of interest.

enum PROJ_INTERMEDIATE_CRS_USE¶

Describe if and how intermediate CRS should be used

Values:

enumerator PROJ_INTERMEDIATE_CRS_USE_ALWAYS¶: Always search for intermediate CRS.

enumerator PROJ_INTERMEDIATE_CRS_USE_IF_NO_DIRECT_TRANSFORMATION¶: Only attempt looking for intermediate CRS if there is no direct transformation available.

enumerator PROJ_INTERMEDIATE_CRS_USE_NEVER¶

enum PJ_COORDINATE_SYSTEM_TYPE¶

Type of coordinate system.

Values:

enumerator PJ_CS_TYPE_UNKNOWN¶

enumerator PJ_CS_TYPE_CARTESIAN¶

enumerator PJ_CS_TYPE_ELLIPSOIDAL¶

enumerator PJ_CS_TYPE_VERTICAL¶

enumerator PJ_CS_TYPE_SPHERICAL¶

enumerator PJ_CS_TYPE_ORDINAL¶

enumerator PJ_CS_TYPE_PARAMETRIC¶

enumerator PJ_CS_TYPE_DATETIMETEMPORAL¶

enumerator PJ_CS_TYPE_TEMPORALCOUNT¶

enumerator PJ_CS_TYPE_TEMPORALMEASURE¶

typedef char **PROJ_STRING_LIST¶: Type representing a NULL terminated list of NULL-terminate strings.

struct PROJ_CRS_INFO¶

#include <proj.h>

Structure given overall description of a CRS.

This structure may grow over time, and should not be directly allocated by client code.

Public Members

char *auth_name¶: Authority name.

char *code¶: Object code.

char *name¶: Object name.

PJ_TYPE type¶: Object type.

int deprecated¶: Whether the object is deprecated

int bbox_valid¶: Whereas the west_lon_degree, south_lat_degree, east_lon_degree and north_lat_degree fields are valid.

double west_lon_degree¶: Western-most longitude of the area of use, in degrees.

double south_lat_degree¶: Southern-most latitude of the area of use, in degrees.

double east_lon_degree¶: Eastern-most longitude of the area of use, in degrees.

double north_lat_degree¶: Northern-most latitude of the area of use, in degrees.

char *area_name¶: Name of the area of use.

char *projection_method_name¶: Name of the projection method for a projected CRS. Might be NULL even for projected CRS in some cases.

char *celestial_body_name¶

Name of the celestial body of the CRS (e.g. “Earth”).

Since: 8.1

struct PROJ_CRS_LIST_PARAMETERS¶

#include <proj.h>

Structure describing optional parameters for proj_get_crs_list();.

This structure may grow over time, and should not be directly allocated by client code.

Public Members

const PJ_TYPE *types¶: Array of allowed object types. Should be NULL if all types are allowed

size_t typesCount¶: Size of types. Should be 0 if all types are allowed

int crs_area_of_use_contains_bbox¶: If TRUE and bbox_valid == TRUE, then only CRS whose area of use entirely contains the specified bounding box will be returned. If FALSE and bbox_valid == TRUE, then only CRS whose area of use intersects the specified bounding box will be returned.

int bbox_valid¶: To set to TRUE so that west_lon_degree, south_lat_degree, east_lon_degree and north_lat_degree fields are taken into account.

double west_lon_degree¶: Western-most longitude of the area of use, in degrees.

double south_lat_degree¶: Southern-most latitude of the area of use, in degrees.

double east_lon_degree¶: Eastern-most longitude of the area of use, in degrees.

double north_lat_degree¶: Northern-most latitude of the area of use, in degrees.

int allow_deprecated¶: Whether deprecated objects are allowed. Default to FALSE.

const char *celestial_body_name¶

Celestial body of the CRS (e.g. “Earth”). The default value, NULL, means no restriction

Since: 8.1

struct PROJ_UNIT_INFO¶

#include <proj.h>

Structure given description of a unit.

This structure may grow over time, and should not be directly allocated by client code.

Since: 7.1

Public Members

char *auth_name¶: Authority name.

char *code¶: Object code.

char *name¶: Object name. For example “metre”, “US survey foot”, etc.

char *category¶: Category of the unit: one of “linear”, “linear_per_time”, “angular”, “angular_per_time”, “scale”, “scale_per_time” or “time”

double conv_factor¶: Conversion factor to apply to transform from that unit to the corresponding SI unit (metre for “linear”, radian for “angular”, etc.). It might be 0 in some cases to indicate no known conversion factor.

char *proj_short_name¶: PROJ short name, like “m”, “ft”, “us-ft”, etc… Might be NULL

int deprecated¶: Whether the object is deprecated

struct PROJ_CELESTIAL_BODY_INFO¶

#include <proj.h>

Structure given description of a celestial body.

This structure may grow over time, and should not be directly allocated by client code.

Since: 8.1

Public Members

char *auth_name¶: Authority name.

char *name¶: Object name. For example “Earth”

Data types¶

Transformation objects¶

2 dimensional coordinates¶

3 dimensional coordinates¶

Spatiotemporal coordinate types¶

Ancillary types for geodetic computations¶

Complex coordinate types¶

Projection derivatives¶

List structures¶

Info structures¶

Error codes¶

Errors in class PROJ_ERR_INVALID_OP¶

Errors in class PROJ_ERR_COORD_TRANSFM¶

Errors in class PROJ_ERR_OTHER¶

Logging¶

Setting custom I/O functions¶

Network related functionality¶

C API for ISO-19111 functionality¶