GTIFDefn Struct Reference

Holds a definition of a coordinate system in normalized form. More...

#include <geo_normalize.h>

Data Fields
short	Model
	From GTModelTypeGeoKey tag.
short	PCS
	From ProjectedCSTypeGeoKey tag.
short	GCS
	From GeographicTypeGeoKey tag.
short	UOMLength
	From ProjLinearUnitsGeoKey.
double	UOMLengthInMeters
	One UOMLength = UOMLengthInMeters meters.
short	UOMAngle
	The angular units of the GCS.
double	UOMAngleInDegrees
	One UOMAngle = UOMLengthInDegrees degrees.
short	Datum
	Datum from GeogGeodeticDatumGeoKey tag.
short	PM
	Prime meridian from GeogPrimeMeridianGeoKey.
double	PMLongToGreenwich
	Decimal degrees of longitude between this prime meridian and Greenwich.
short	Ellipsoid
	Ellipsoid identifier from GeogELlipsoidGeoKey.
double	SemiMajor
	The length of the semi major ellipse axis in meters.
double	SemiMinor
	The length of the semi minor ellipse axis in meters.
short	ProjCode
	Projection id from ProjectionGeoKey.
short	Projection
	EPSG identifier for underlying projection method.
short	CTProjection
	GeoTIFF identifier for underlying projection method.
int	nParms
	Number of projection parameters in ProjParm and ProjParmId.
double	ProjParm [MAX_GTIF_PROJPARMS]
	Projection parameter value.
int	ProjParmId [MAX_GTIF_PROJPARMS]
	Projection parameter identifier.
int	MapSys
	Special zone map system code (MapSys_UTM_South, MapSys_UTM_North, MapSys_State_Plane or KvUserDefined if none apply.
int	Zone
	UTM, or State Plane Zone number, zero if not known.
int	DefnSet
	Do we have any definition at all? 0 if no geokeys found.

Detailed Description

Holds a definition of a coordinate system in normalized form.

Field Documentation

short GTIFDefn::CTProjection

GeoTIFF identifier for underlying projection method.

While some of these values have corresponding vlaues in EPSG (Projection field), others do not. For example CT_TransverseMercator.

Referenced by GTIFGetDefn().

short GTIFDefn::Datum

Datum from GeogGeodeticDatumGeoKey tag.

For example Datum_WGS84

Referenced by GTIFGetDefn().

short GTIFDefn::Ellipsoid

Ellipsoid identifier from GeogELlipsoidGeoKey.

For example Ellipse_Clarke_1866.

Referenced by GTIFGetDefn().

short GTIFDefn::GCS

From GeographicTypeGeoKey tag.

For example GCS_WGS_84 or GCS_Voirol_1875_Paris. Includes datum and prime meridian value.

Referenced by GTIFGetDefn().

int GTIFDefn::MapSys

Special zone map system code (MapSys_UTM_South, MapSys_UTM_North, MapSys_State_Plane or KvUserDefined if none apply.

Referenced by GTIFGetDefn().

short GTIFDefn::Model

From GTModelTypeGeoKey tag.

Can have the values ModelTypeGeographic or ModelTypeProjected.

Referenced by GTIFGetDefn().

int GTIFDefn::nParms

Number of projection parameters in ProjParm and ProjParmId.

Referenced by GTIFGetDefn().

short GTIFDefn::PCS

From ProjectedCSTypeGeoKey tag.

For example PCS_NAD27_UTM_zone_3N.

Referenced by GTIFGetDefn().

short GTIFDefn::PM

Prime meridian from GeogPrimeMeridianGeoKey.

For example PM_Greenwich or PM_Paris.

Referenced by GTIFGetDefn().

double GTIFDefn::PMLongToGreenwich

Decimal degrees of longitude between this prime meridian and Greenwich.

Prime meridians to the west of Greenwich are negative.

Referenced by GTIFGetDefn().

short GTIFDefn::ProjCode

Projection id from ProjectionGeoKey.

For example Proj_UTM_11S.

Referenced by GTIFGetDefn().

short GTIFDefn::Projection

EPSG identifier for underlying projection method.

From the EPSG TRF_METHOD table.

Referenced by GTIFGetDefn().

double GTIFDefn::ProjParm[MAX_GTIF_PROJPARMS]

Projection parameter value.

The identify of this parameter is established from the corresponding entry in ProjParmId. The value will be measured in meters, or decimal degrees if it is a linear or angular measure.

Referenced by GTIFGetDefn().

int GTIFDefn::ProjParmId[MAX_GTIF_PROJPARMS]

Projection parameter identifier.

For example ProjFalseEastingGeoKey. The value will be 0 for unused table entries.

Referenced by GTIFGetDefn().

double GTIFDefn::SemiMajor

The length of the semi major ellipse axis in meters.

Referenced by GTIFGetDefn().

double GTIFDefn::SemiMinor

The length of the semi minor ellipse axis in meters.

Referenced by GTIFGetDefn().

short GTIFDefn::UOMAngle