OGReMeC++ C++ API

OGRFeature类

classOGRFeature

A simple feature, including geometry and attributes.

公共职能

OGRFeature(OGRFeatureDefn*)

Constructor.

Note that the OGRFeature will increment the reference count of its defining OGRFeatureDefn. Destruction of the OGRFeatureDefn before destruction of all OGRFeatures that depend on it is likely to result in a crash.

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

Parameters

poDefnIn: feature class (layer) definition to which the feature will adhere.

ConstFieldIteratorbegin()const

Return begin of field value iterator.

Using this iterator for standard range-based loops is safe, but due to implementation limitations, you shouldn't try to access (dereference) more than one iterator step at a time, since you will get a reference to the same object (FieldValue) at each iteration step.

Since

GDAL 2.3

ConstFieldIteratorend()const

Return end of field value iterator.

constFieldValueoperator[](int iField)const

Return a field value.

Return

the field value.

Since

GDAL 2.3

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1. This is not checked by the method !

FieldValueoperator[](int iField)

Return a field value.

Return

the field value.

Since

GDAL 2.3

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1. This is not checked by the method !

constFieldValueoperator[](const char *pszFieldName)const

Return a field value.

Return

the field value, or throw a FieldNotFoundException if not found.

Since

GDAL 2.3

Parameters

pszFieldName: field name

FieldValueoperator[](const char *pszFieldName)

Return a field value.

Return

the field value, or throw a FieldNotFoundException if not found.

Since

GDAL 2.3

Parameters

pszFieldName: field name

OGRFeatureDefn *GetDefnRef()

Fetch feature definition.

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

This method is the same as the C function

OGR_F_GetDefnRef().

Return

a reference to the feature definition object.

Return

a reference to the feature definition object.

Since

GDAL 2.3

OGRErrSetGeometryDirectly(OGRGeometry*)

Set feature geometry.

This method updates the features geometry, and operate exactly as SetGeometry(), except that this method assumes ownership of the passed geometry (even in case of failure of that function).

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

Note

This method has only an effect on the in-memory feature object. If this object comes from a layer and the modifications must be serialized back to the datasource, OGR_L_SetFeature() must be used afterwards. Or if this is a new feature, OGR_L_CreateFeature() must be used afterwards.

Return

OGRERR_NONE if successful, or OGR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the OGRFeatureDefn (checking not yet implemented).

Parameters

poGeomIn: new geometry to apply to feature. Passing NULL value here is correct and it will result in deallocation of currently assigned geometry without assigning new one.

OGRErrSetGeometry(constOGRGeometry*)

Set feature geometry.

This method updates the features geometry, and operate exactly as SetGeometryDirectly(), except that this method does not assume ownership of the passed geometry, but instead makes a copy of it.

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

Note

Return

OGRERR_NONE if successful, or OGR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the OGRFeatureDefn (checking not yet implemented).

Parameters

poGeomIn: new geometry to apply to feature. Passing NULL value here is correct and it will result in deallocation of currently assigned geometry without assigning new one.

OGRGeometry *GetGeometryRef()

Fetch pointer to feature geometry.

This method is essentially the same as the C function OGR_F_GetGeometryRef(). (the only difference is that the C function honours OGRGetNonLinearGeometriesEnabledFlag())

Starting with GDAL 1.11, this is equivalent to calling OGRFeature::GetGeomFieldRef(0).

This method is essentially the same as the C function

OGR_F_GetGeometryRef(). (the only difference is that the C function honours OGRGetNonLinearGeometriesEnabledFlag())

Return

pointer to internal feature geometry. This object should not be modified.

Return

pointer to internal feature geometry. This object should not be modified.

Since

GDAL 2.3

OGRGeometry *StealGeometry()

Take away ownership of geometry.

Fetch the geometry from this feature, and clear the reference to the geometry on the feature. This is a mechanism for the application to take over ownership of the geometry from the feature without copying. Sort of an inverse to SetGeometryDirectly().

After this call the OGRFeature will have a NULL geometry.

Return

the pointer to the geometry.

int GetGeomFieldCount()const

Fetch number of geometry fields on this feature. This will always be the same as the geometry field count for the OGRFeatureDefn.

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

Return

count of geometry fields.

Since

GDAL 1.11

OGRGeomFieldDefn *GetGeomFieldDefnRef(int iField)

Fetch definition for this geometry field.

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

Return

the field definition (from the OGRFeatureDefn). This is an internal reference, and should not be deleted or modified.

Since

GDAL 1.11

Parameters

iGeomField: the field to fetch, from 0 to GetGeomFieldCount()-1.

constOGRGeomFieldDefn *GetGeomFieldDefnRef(int iField)const

Fetch definition for this geometry field.

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

Return

the field definition (from the OGRFeatureDefn). This is an internal reference, and should not be deleted or modified.

Since

GDAL 2.3

Parameters

iGeomField: the field to fetch, from 0 to GetGeomFieldCount()-1.

int GetGeomFieldIndex(const char *pszName)const

Fetch the geometry field index given geometry field name.

This is a cover for the OGRFeatureDefn::GetGeomFieldIndex() method.

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

Return

the geometry field index, or -1 if no matching geometry field is found.

Since

GDAL 1.11

Parameters

pszName: the name of the geometry field to search for.

OGRGeometry *GetGeomFieldRef(int iField)

Fetch pointer to feature geometry.

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

Return

pointer to internal feature geometry. This object should not be modified.

Since

GDAL 1.11

Parameters

iField: geometry field to get.

constOGRGeometry *GetGeomFieldRef(int iField)const

Fetch pointer to feature geometry.

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

Return

pointer to internal feature geometry. This object should not be modified.

Since

GDAL 2.3

Parameters

iField: geometry field to get.

OGRGeometry *StealGeometry(int iField)

Take away ownership of geometry.

After this call the OGRFeature will have a NULL geometry.

Return

the pointer to the geometry.

Parameters

iGeomField: index of the geometry field.

OGRGeometry *GetGeomFieldRef(const char *pszFName)

Fetch pointer to feature geometry.

Return

pointer to internal feature geometry. This object should not be modified.

Since

GDAL 1.11

Parameters

pszFName: name of geometry field to get.

constOGRGeometry *GetGeomFieldRef(const char *pszFName)const

Fetch pointer to feature geometry.

Return

pointer to internal feature geometry. This object should not be modified.

Since

GDAL 2.3

Parameters

pszFName: name of geometry field to get.

OGRErrSetGeomFieldDirectly(int iField, OGRGeometry*)

Set feature geometry of a specified geometry field.

This method updates the features geometry, and operate exactly as SetGeomField(), except that this method assumes ownership of the passed geometry (even in case of failure of that function).

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

Return

OGRERR_NONE if successful, or OGRERR_FAILURE if the index is invalid, or OGRERR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the OGRFeatureDefn (checking not yet implemented).

Since

GDAL 1.11

Parameters

iField: geometry field to set.
poGeomIn: new geometry to apply to feature. Passing NULL value here is correct and it will result in deallocation of currently assigned geometry without assigning new one.

OGRErrSetGeomField(int iField, constOGRGeometry*)

Set feature geometry of a specified geometry field.

This method updates the features geometry, and operate exactly as SetGeomFieldDirectly(), except that this method does not assume ownership of the passed geometry, but instead makes a copy of it.

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

Return

OGRERR_NONE if successful, or OGRERR_FAILURE if the index is invalid, or OGR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the OGRFeatureDefn (checking not yet implemented).

Since

GDAL 1.11

Parameters

iField: geometry field to set.
poGeomIn: new geometry to apply to feature. Passing NULL value here is correct and it will result in deallocation of currently assigned geometry without assigning new one.

OGRFeature *Clone()const

Duplicate feature.

The newly created feature is owned by the caller, and will have its own reference to the OGRFeatureDefn.

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

Return

new feature, exactly matching this feature. Or, starting with GDAL 2.1, NULL in case of out of memory situation.

OGRBooleanEqual(constOGRFeature *poFeature)const

Test if two features are the same.

Two features are considered equal if the share them (pointer equality) same OGRFeatureDefn, have the same field values, and the same geometry (as tested by OGRGeometry::Equal()) as well as the same feature id.

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

Return

TRUE if they are equal, otherwise FALSE.

Parameters

poFeature: the other feature to test this one against.

int GetFieldCount()const

Fetch number of fields on this feature. This will always be the same as the field count for the OGRFeatureDefn.

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

Return

count of fields.

constOGRFieldDefn *GetFieldDefnRef(int iField)const

Fetch definition for this field.

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

Return

the field definition (from the OGRFeatureDefn). This is an internal reference, and should not be deleted or modified.

Since

GDAL 2.3

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.

OGRFieldDefn *GetFieldDefnRef(int iField)

Fetch definition for this field.

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

Return

the field definition (from the OGRFeatureDefn). This is an internal reference, and should not be deleted or modified.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.

int GetFieldIndex(const char *pszName)const

Fetch the field index given field name.

This is a cover for the OGRFeatureDefn::GetFieldIndex() method.

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

Return

the field index, or -1 if no matching field is found.

Parameters

pszName: the name of the field to search for.

int IsFieldSet(int iField)const

Test if a field has ever been assigned a value or not.

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

Return

TRUE if the field has been set, otherwise false.

Parameters

iField: the field to test.

void UnsetField(int iField)

Clear a field, marking it as unset.

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

Parameters

iField: the field to unset.

bool IsFieldNull(int iField)const

Test if a field is null.

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

Return

TRUE if the field is null, otherwise false.

Since

GDAL 2.2

Parameters

iField: the field to test.

void SetFieldNull(int iField)

Clear a field, marking it as null.

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

Since

GDAL 2.2

Parameters

iField: the field to set to null.

bool IsFieldSetAndNotNull(int iField)const

Test if a field is set and not null.

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

Return

TRUE if the field is set and not null, otherwise false.

Since

GDAL 2.2

Parameters

iField: the field to test.

OGRField *GetRawFieldRef(int i)

Fetch a pointer to the internal field value given the index.

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

Return

the returned pointer is to an internal data structure, and should not be freed, or modified.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.

constOGRField *GetRawFieldRef(int i)const

Fetch a pointer to the internal field value given the index.

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

Return

the returned pointer is to an internal data structure, and should not be freed, or modified.

Since

GDAL 2.3

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.

int GetFieldAsInteger(int i)const

Fetch field value as integer.

OFTString features will be translated using atoi(). OFTReal fields will be cast to integer. OFTInteger64 are demoted to 32 bit, with clamping if out-of-range. Other field types, or errors will result in a return value of zero.

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

Return

the field value.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.

GIntBigGetFieldAsInteger64(int i)const

Fetch field value as integer 64 bit.

OFTInteger are promoted to 64 bit. OFTString features will be translated using CPLAtoGIntBig(). OFTReal fields will be cast to integer. Other field types, or errors will result in a return value of zero.

This method is the same as the C function OGR_F_GetFieldAsInteger64().

Return

the field value.

Since

GDAL 2.0

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.

double GetFieldAsDouble(int i)const

Fetch field value as a double.

OFTString features will be translated using CPLAtof(). OFTInteger and OFTInteger64 fields will be cast to double. Other field types, or errors will result in a return value of zero.

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

Return

the field value.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.

const char *GetFieldAsString(int i)const

Fetch field value as a string.

OFTReal and OFTInteger fields will be translated to string using sprintf(), but not necessarily using the established formatting rules. Other field types, or errors will result in a return value of zero.

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

Return

the field value. This string is internal, and should not be modified, or freed. Its lifetime may be very brief.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.

const int *GetFieldAsIntegerList(int i, int *pnCount)const

Fetch field value as a list of integers.

Currently this method only works for OFTIntegerList fields.

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

Return

the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief. If *pnCount is zero on return the returned pointer may be NULL or non-NULL.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
pnCount: an integer to put the list count (number of integers) into.

constGIntBig *GetFieldAsInteger64List(int i, int *pnCount)const

Fetch field value as a list of 64 bit integers.

Currently this method only works for OFTInteger64List fields.

This method is the same as the C function OGR_F_GetFieldAsInteger64List().

Return

the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief. If *pnCount is zero on return the returned pointer may be NULL or non-NULL.

Since

GDAL 2.0

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
pnCount: an integer to put the list count (number of integers) into.

const double *GetFieldAsDoubleList(int i, int *pnCount)const

Fetch field value as a list of doubles.

Currently this method only works for OFTRealList fields.

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

Return

the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief. If *pnCount is zero on return the returned pointer may be NULL or non-NULL.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
pnCount: an integer to put the list count (number of doubles) into.

char **GetFieldAsStringList(int i)const

Fetch field value as a list of strings.

Currently this method only works for OFTStringList fields.

The returned list is terminated by a NULL pointer. The number of elements can also be calculated using CSLCount().

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

Return

the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.

GByte *GetFieldAsBinary(int i, int *pnCount)const

Fetch field value as binary data.

This method only works for OFTBinary and OFTString fields.

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

Return

the field value. This data is internal, and should not be modified, or freed. Its lifetime may be very brief.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
pnBytes: location to put the number of bytes returned.

int GetFieldAsDateTime(int i, int *pnYear, int *pnMonth, int *pnDay, int *pnHour, int *pnMinute, int *pnSecond, int *pnTZFlag)const

Fetch field value as date and time.

Currently this method only works for OFTDate, OFTTime and OFTDateTime fields.

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

Return

TRUE on success or FALSE on failure.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
pnYear: (including century)
pnMonth: (1-12)
pnDay: (1-31)
pnHour: (0-23)
pnMinute: (0-59)
pnSecond: (0-59)
pnTZFlag: (0=unknown, 1=localtime, 100=GMT, see data model for details)

int GetFieldAsDateTime(int i, int *pnYear, int *pnMonth, int *pnDay, int *pnHour, int *pnMinute, float *pfSecond, int *pnTZFlag)const

Fetch field value as date and time.

Currently this method only works for OFTDate, OFTTime and OFTDateTime fields.

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

Return

TRUE on success or FALSE on failure.

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
pnYear: (including century)
pnMonth: (1-12)
pnDay: (1-31)
pnHour: (0-23)
pnMinute: (0-59)
pfSecond: (0-59 with millisecond accuracy)
pnTZFlag: (0=unknown, 1=localtime, 100=GMT, see data model for details)

char *GetFieldAsSerializedJSon(int i)const

Fetch field value as a serialized JSon object.

Currently this method only works for OFTStringList, OFTIntegerList, OFTInteger64List and OFTRealList

Return

a string that must be de-allocate with CPLFree()

Since

GDAL 2.2

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.

int GetFieldAsInteger(const char *pszFName)const

Fetch field value as integer.

Return

the field value.

Parameters

pszFName: the name of the field to fetch.

GIntBigGetFieldAsInteger64(const char *pszFName)const

Fetch field value as integer 64 bit.

Return

the field value.

Parameters

pszFName: the name of the field to fetch.

double GetFieldAsDouble(const char *pszFName)const

Fetch field value as a double.

OFTString features will be translated using CPLAtof(). OFTInteger and OFTInteger64 fields will be cast to double. Other field types, or errors will result in a return value of zero.

Return

the field value.

Parameters

pszFName: the name of the field to fetch.

const char *GetFieldAsString(const char *pszFName)const

Fetch field value as a string.

Return

the field value. This string is internal, and should not be modified, or freed. Its lifetime may be very brief.

Parameters

pszFName: the name of the field to fetch.

const int *GetFieldAsIntegerList(const char *pszFName, int *pnCount)const

Fetch field value as a list of integers.

Currently this method only works for OFTIntegerList fields.

Return

the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief. If *pnCount is zero on return the returned pointer may be NULL or non-NULL. OFTReal and OFTInteger fields will be translated to string using sprintf(), but not necessarily using the established formatting rules. Other field types, or errors will result in a return value of zero.

Parameters

pszFName: the name of the field to fetch.
pnCount: an integer to put the list count (number of integers) into.

constGIntBig *GetFieldAsInteger64List(const char *pszFName, int *pnCount)const

Fetch field value as a list of 64 bit integers.

Currently this method only works for OFTInteger64List fields.

Return

the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief. If *pnCount is zero on return the returned pointer may be NULL or non-NULL.

Since

GDAL 2.0

Parameters

pszFName: the name of the field to fetch.
pnCount: an integer to put the list count (number of integers) into.

const double *GetFieldAsDoubleList(const char *pszFName, int *pnCount)const

Fetch field value as a list of doubles.

Currently this method only works for OFTRealList fields.

Return

the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief. If *pnCount is zero on return the returned pointer may be NULL or non-NULL.

Parameters

pszFName: the name of the field to fetch.
pnCount: an integer to put the list count (number of doubles) into.

char **GetFieldAsStringList(const char *pszFName)const

Fetch field value as a list of strings.

Currently this method only works for OFTStringList fields.

The returned list is terminated by a NULL pointer. The number of elements can also be calculated using CSLCount().

Return

the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief.

Parameters

pszFName: the name of the field to fetch.

void SetField(int i, int nValue)

Set field to integer value.

OFTInteger, OFTInteger64 and OFTReal fields will be set directly. OFTString fields will be assigned a string representation of the value, but not necessarily taking into account formatting constraints on this field. Other field types may be unaffected.

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

Note

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
nValue: the value to assign.

void SetField(int i, GIntBignValue)

Set field to 64 bit integer value.

This method is the same as the C function OGR_F_SetFieldInteger64().

Note

Since

GDAL 2.0

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
nValue: the value to assign.

void SetField(int i, double dfValue)

Set field to double value.

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

Note

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
dfValue: the value to assign.

void SetField(int i, const char *pszValue)

Set field to string value.

OFTInteger fields will be set based on an atoi() conversion of the string. OFTInteger64 fields will be set based on an CPLAtoGIntBig() conversion of the string. OFTReal fields will be set based on an CPLAtof() conversion of the string. Other field types may be unaffected.

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

Note

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
pszValue: the value to assign.

void SetField(int i, int nCount, const int *panValues)

Set field to list of integers value.

This method currently on has an effect of OFTIntegerList, OFTInteger64List and OFTRealList fields.

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

Note

Parameters

iField: the field to set, from 0 to GetFieldCount()-1.
nCount: the number of values in the list being assigned.
panValues: the values to assign.

void SetField(int i, int nCount, constGIntBig *panValues)

Set field to list of 64 bit integers value.

This method currently on has an effect of OFTIntegerList, OFTInteger64List and OFTRealList fields.

This method is the same as the C function OGR_F_SetFieldInteger64List().

Note

Since

GDAL 2.0

Parameters

iField: the field to set, from 0 to GetFieldCount()-1.
nCount: the number of values in the list being assigned.
panValues: the values to assign.

void SetField(int i, int nCount, const double *padfValues)

Set field to list of doubles value.

This method currently on has an effect of OFTIntegerList, OFTInteger64List, OFTRealList fields.

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

Note

Parameters

iField: the field to set, from 0 to GetFieldCount()-1.
nCount: the number of values in the list being assigned.
padfValues: the values to assign.

void SetField(int i, const char *const *papszValues)

Set field to list of strings value.

This method currently on has an effect of OFTStringList fields.

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

Note

Parameters

iField: the field to set, from 0 to GetFieldCount()-1.
papszValues: the values to assign. List of NUL-terminated string, ending with a NULL pointer.

void SetField(int i, OGRField *puValue)

Set field.

The passed value OGRField must be of exactly the same type as the target field, or an application crash may occur. The passed value is copied, and will not be affected. It remains the responsibility of the caller.

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

Note

Parameters

iField: the field to fetch, from 0 to GetFieldCount()-1.
puValue: the value to assign.

void SetField(int i, int nCount, const void *pabyBinary)

Set field to binary data.

This method currently on has an effect of OFTBinary fields.

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

Note

Parameters

iField: the field to set, from 0 to GetFieldCount()-1.
nBytes: bytes of data being set.
pabyData: the raw data being applied.

void SetField(int i, int nYear, int nMonth, int nDay, int nHour = 0, int nMinute = 0, float fSecond = 0.f, int nTZFlag = 0)

Set field to date.

This method currently only has an effect for OFTDate, OFTTime and OFTDateTime fields.

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

Note

Parameters

iField: the field to set, from 0 to GetFieldCount()-1.
nYear: (including century)
nMonth: (1-12)
nDay: (1-31)
nHour: (0-23)
nMinute: (0-59)
fSecond: (0-59, with millisecond accuracy)
nTZFlag: (0=unknown, 1=localtime, 100=GMT, see data model for details)

void SetField(const char *pszFName, int nValue)

Set field to integer value. OFTInteger, OFTInteger64 and OFTReal fields will be set directly. OFTString fields will be assigned a string representation of the value, but not necessarily taking into account formatting constraints on this field. Other field types may be unaffected.

Note

Parameters

pszFName: the name of the field to set.
nValue: the value to assign.

void SetField(const char *pszFName, GIntBignValue)

Set field to 64 bit integer value. OFTInteger, OFTInteger64 and OFTReal fields will be set directly. OFTString fields will be assigned a string representation of the value, but not necessarily taking into account formatting constraints on this field. Other field types may be unaffected.

Note

Parameters

pszFName: the name of the field to set.
nValue: the value to assign.

void SetField(const char *pszFName, double dfValue)

Set field to double value.

Note

Parameters

pszFName: the name of the field to set.
dfValue: the value to assign.

void SetField(const char *pszFName, const char *pszValue)

Set field to string value.

Note

Parameters

pszFName: the name of the field to set.
pszValue: the value to assign.

void SetField(const char *pszFName, int nCount, const int *panValues)

Set field to list of integers value.

This method currently on has an effect of OFTIntegerList, OFTInteger64List and OFTRealList fields.

Note

Parameters

pszFName: the name of the field to set.
nCount: the number of values in the list being assigned.
panValues: the values to assign.

void SetField(const char *pszFName, int nCount, constGIntBig *panValues)

Set field to list of 64 bit integers value.

This method currently on has an effect of OFTIntegerList, OFTInteger64List and OFTRealList fields.

Note

Parameters

pszFName: the name of the field to set.
nCount: the number of values in the list being assigned.
panValues: the values to assign.

void SetField(const char *pszFName, int nCount, const double *padfValues)

Set field to list of doubles value.

This method currently on has an effect of OFTIntegerList, OFTInteger64List, OFTRealList fields.

Note

Parameters

pszFName: the name of the field to set.
nCount: the number of values in the list being assigned.
padfValues: the values to assign.

void SetField(const char *pszFName, const char *const *papszValues)

Set field to list of strings value.

This method currently on has an effect of OFTStringList fields.

Note

Parameters

pszFName: the name of the field to set.
papszValues: the values to assign. List of NUL-terminated string, ending with a NULL pointer.

void SetField(const char *pszFName, OGRField *puValue)

Set field.

Note

Parameters

pszFName: the name of the field to set.
puValue: the value to assign.

void SetField(const char *pszFName, int nYear, int nMonth, int nDay, int nHour = 0, int nMinute = 0, float fSecond = 0.f, int nTZFlag = 0)

Set field to date.

This method currently only has an effect for OFTDate, OFTTime and OFTDateTime fields.

Note

Parameters

pszFName: the name of the field to set.
nYear: (including century)
nMonth: (1-12)
nDay: (1-31)
nHour: (0-23)
nMinute: (0-59)
fSecond: (0-59, with millisecond accuracy)
nTZFlag: (0=unknown, 1=localtime, 100=GMT, see data model for details)

GIntBigGetFID()const

Get feature identifier.

This method is the same as the C function OGR_F_GetFID(). Note: since GDAL 2.0, this method returns a GIntBig (previously a long)

Return

feature id or OGRNullFID if none has been assigned.

OGRErrSetFID(GIntBignFIDIn)

Set the feature identifier.

For specific types of features this operation may fail on illegal features ids. Generally it always succeeds. Feature ids should be greater than or equal to zero, with the exception of OGRNullFID (-1) indicating that the feature id is unknown.

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

Return

On success OGRERR_NONE, or on failure some other value.

Parameters

nFIDIn: the new feature identifier value to assign.

void DumpReadable(FILE*, char **papszOptions = nullptr)const

Dump this feature in a human readable form.

This dumps the attributes, and geometry; however, it doesn't definition information (other than field types and names), nor does it report the geometry spatial reference system.

A few options can be defined to change the default dump :

DISPLAY_FIELDS=NO : to hide the dump of the attributes
DISPLAY_STYLE=NO : to hide the dump of the style string
DISPLAY_GEOMETRY=NO : to hide the dump of the geometry
DISPLAY_GEOMETRY=SUMMARY : to get only a summary of the geometry

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

Parameters

fpOut: the stream to write to, such as stdout. If NULL stdout will be used.
papszOptions: NULL terminated list of options (may be NULL)

OGRErrSetFrom(constOGRFeature*, int = TRUE)

Set one feature from another.

Overwrite the contents of this feature from the geometry and attributes of another. The poSrcFeature does not need to have the same OGRFeatureDefn. Field values are copied by corresponding field names. Field types do not have to exactly match. SetField() method conversion rules will be applied as needed.

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

Return

OGRERR_NONE if the operation succeeds, even if some values are not transferred, otherwise an error code.

Parameters

poSrcFeature: the feature from which geometry, and field values will be copied.
bForgiving: TRUE if the operation should continue despite lacking output fields matching some of the source fields.

OGRErrSetFrom(constOGRFeature*, const int*, int = TRUE)

Set one feature from another.

Overwrite the contents of this feature from the geometry and attributes of another. The poSrcFeature does not need to have the same OGRFeatureDefn. Field values are copied according to the provided indices map. Field types do not have to exactly match. SetField() method conversion rules will be applied as needed. This is more efficient than OGR_F_SetFrom() in that this doesn't lookup the fields by their names. Particularly useful when the field names don't match.

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

Return

OGRERR_NONE if the operation succeeds, even if some values are not transferred, otherwise an error code.

Parameters

poSrcFeature: the feature from which geometry, and field values will be copied.
panMap: Array of the indices of the feature's fields stored at the corresponding index of the source feature's fields. A value of -1 should be used to ignore the source's field. The array should not be NULL and be as long as the number of fields in the source feature.
bForgiving: TRUE if the operation should continue despite lacking output fields matching some of the source fields.

OGRErrSetFieldsFrom(constOGRFeature*, const int*, int = TRUE)

Set fields from another feature.

Overwrite the fields of this feature from the attributes of another. The FID and the style string are not set. The poSrcFeature does not need to have the same OGRFeatureDefn. Field values are copied according to the provided indices map. Field types do not have to exactly match. SetField() method conversion rules will be applied as needed. This is more efficient than OGR_F_SetFrom() in that this doesn't lookup the fields by their names. Particularly useful when the field names don't match.

Return

OGRERR_NONE if the operation succeeds, even if some values are not transferred, otherwise an error code.

Parameters

poSrcFeature: the feature from which geometry, and field values will be copied.
panMap: Array of the indices of the feature's fields stored at the corresponding index of the source feature's fields. A value of -1 should be used to ignore the source's field. The array should not be NULL and be as long as the number of fields in the source feature.
bForgiving: TRUE if the operation should continue despite lacking output fields matching some of the source fields.

int Validate(int nValidateFlags, int bEmitError)const

Validate that a feature meets constraints of its schema.

The scope of test is specified with the nValidateFlags parameter.

Regarding OGR_F_VAL_WIDTH, the test is done assuming the string width must be interpreted as the number of UTF-8 characters. Some drivers might interpret the width as the number of bytes instead. So this test is rather conservative (if it fails, then it will fail for all interpretations).

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

Return

TRUE if all enabled validation tests pass.

Since

GDAL 2.0

Parameters

nValidateFlags: OGR_F_VAL_ALL or combination of OGR_F_VAL_NULL, OGR_F_VAL_GEOM_TYPE, OGR_F_VAL_WIDTH and OGR_F_VAL_ALLOW_NULL_WHEN_DEFAULT, OGR_F_VAL_ALLOW_DIFFERENT_GEOM_DIM with '|' operator
bEmitError: TRUE if a CPLError() must be emitted when a check fails

void FillUnsetWithDefault(int bNotNullableOnly, char **papszOptions)

Fill unset fields with default values that might be defined.

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

Since

GDAL 2.0

Parameters

bNotNullableOnly: if we should fill only unset fields with a not-null constraint.
papszOptions: unused currently. Must be set to NULL.

const char *GetStyleString()const

Fetch style string for this feature.

Set the OGR Feature Style Specification for details on the format of this string, and ogr_featurestyle.h for services available to parse it.

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

Return

a reference to a representation in string format, or NULL if there isn't one.

void SetStyleString(const char*)

Set feature style string.

This method operate exactly as OGRFeature::SetStyleStringDirectly() except that it does not assume ownership of the passed string, but instead makes a copy of it.

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

Parameters

pszString: the style string to apply to this feature, cannot be NULL.

void SetStyleStringDirectly(char*)

Set feature style string.

This method operate exactly as OGRFeature::SetStyleString() except that it assumes ownership of the passed string.

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

Parameters

pszString: the style string to apply to this feature, cannot be NULL.

OGRStyleTable *GetStyleTable()const

Return style table.

Return

style table.

void SetStyleTable(OGRStyleTable *poStyleTable)

Set style table.

Parameters

poStyleTable: new style table (will be cloned)

void SetStyleTableDirectly(OGRStyleTable *poStyleTable)

Set style table.

Parameters

poStyleTable: new style table (ownership transferred to the object)

const char *GetNativeData()const

Returns the native data for the feature.

The native data is the representation in a "natural" form that comes from the driver that created this feature, or that is aimed at an output driver. The native data may be in different format, which is indicated by GetNativeMediaType().

Note that most drivers do not support storing the native data in the feature object, and if they do, generally the NATIVE_DATA open option must be passed at dataset opening.

The "native data" does not imply it is something more performant or powerful than what can be obtained with the rest of the API, but it may be useful in round-tripping scenarios where some characteristics of the underlying format are not captured otherwise by the OGR abstraction.

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

Return

a string with the native data, or NULL if there is none.

Since

GDAL 2.1

See

rfc60_improved_roundtripping_in_ogr – GDAL

const char *GetNativeMediaType()const

Returns the native media type for the feature.

The native media type is the identifier for the format of the native data. It follows the IANA RFC 2045 (see https://en.wikipedia.org/wiki/Media_type), e.g. "application/vnd.geo+json" for JSon.

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

Return

a string with the native media type, or NULL if there is none.

Since

GDAL 2.1

See

rfc60_improved_roundtripping_in_ogr – GDAL

void SetNativeData(const char *pszNativeData)

Sets the native data for the feature.

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

Since

GDAL 2.1

See

rfc60_improved_roundtripping_in_ogr – GDAL

Parameters

pszNativeData: a string with the native data, or NULL if there is none.

void SetNativeMediaType(const char *pszNativeMediaType)

Sets the native media type for the feature.

The native media type is the identifier for the format of the native data. It follows the IANA RFC 2045 (see https://en.wikipedia.org/wiki/Media_type), e.g. "application/vnd.geo+json" for JSon.

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

Since

GDAL 2.1

See

rfc60_improved_roundtripping_in_ogr – GDAL

Parameters

pszNativeMediaType: a string with the native media type, or NULL if there is none.

公共静态函数

OGRFeature *CreateFeature(OGRFeatureDefn*)

Feature factory.

This is essentially a feature factory, useful for applications creating features but wanting to ensure they are created out of the OGR/GDAL heap.

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

Return

new feature object with null fields and no geometry, or, starting with GDAL 2.1, NULL in case of out of memory situation. May be deleted with DestroyFeature().

Parameters

poDefn: Feature definition defining schema.

void DestroyFeature(OGRFeature*)

Destroy feature.

The feature is deleted, but within the context of the GDAL/OGR heap. This is necessary when higher level applications use GDAL/OGR from a DLL and they want to delete a feature created within the DLL. If the delete is done in the calling application the memory will be freed onto the application heap which is inappropriate.

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

Parameters

poFeature: the feature to delete.

OGRFeatureHToHandle(OGRFeature *poFeature)

Convert a OGRFeature* to a OGRFeatureH.

Since

GDAL 2.3

OGRFeature *FromHandle(OGRFeatureHhFeature)

Convert a OGRFeatureH to a OGRFeature*.

Since

GDAL 2.3

classConstFieldIterator

Field value iterator class.

structPrivate

classFieldNotFoundException : public exception

Exception raised by operator[](const char*) when a field is not found.

classFieldValue

Field value.

公共职能

FieldValue &operator=(constFieldValue &oOther)

Set a field value from another one.

FieldValue &operator=(int nVal)

Set an integer value to the field.

FieldValue &operator=(GIntBignVal)

Set an integer value to the field.

FieldValue &operator=(double dfVal)

Set a real value to the field.

FieldValue &operator=(const char *pszVal)

Set a string value to the field.

FieldValue &operator=(const std::string &osVal)

Set a string value to the field.

FieldValue &operator=(const std::vector<int> &oArray)

Set an array of integer to the field.

FieldValue &operator=(const std::vector<GIntBig> &oArray)

Set an array of big integer to the field.

FieldValue &operator=(const std::vector<double> &oArray)

Set an array of double to the field.

FieldValue &operator=(const std::vector<std::string> &oArray)

Set an array of strings to the field.

FieldValue &operator=(CSLConstListpapszValues)

Set an array of strings to the field.

void SetNull()

Set a null value to the field.

void clear()

Unset the field.

void Unset()

Unset the field.

void SetDateTime(int nYear, int nMonth, int nDay, int nHour = 0, int nMinute = 0, float fSecond = 0.f, int nTZFlag = 0)

Set date time value/.

int GetIndex()const

Return field index.

constOGRFieldDefn *GetDefn()const

Return field definition.

const char *GetName()const

Return field name.

OGRFieldTypeGetType()const

Return field type.

OGRFieldSubTypeGetSubType()const

Return field subtype.

bool empty()const

Return whether the field value is unset/empty.

bool IsUnset()const

Return whether the field value is unset/empty.

bool IsNull()const

Return whether the field value is null.

constOGRField *GetRawValue()const

Return the raw field value.

int GetInteger()const

Return the integer value.

Only use that method if and only if GetType() == OFTInteger.

GIntBigGetInteger64()const

Return the 64-bit integer value.

Only use that method if and only if GetType() == OFTInteger64.

double GetDouble()const

Return the double value.

Only use that method if and only if GetType() == OFTReal.

const char *GetString()const

Return the string value.

Only use that method if and only if GetType() == OFTString.

bool GetDateTime(int *pnYear, int *pnMonth, int *pnDay, int *pnHour, int *pnMinute, float *pfSecond, int *pnTZFlag)const

Return the date/time/datetime value.

operator int()const

Return the field value as integer, with potential conversion.

operator GIntBig()const

Return the field value as 64-bit integer, with potential conversion.

operator double()const

Return the field value as double, with potential conversion.

operator const char*()const

Return the field value as string, with potential conversion.

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

Return the field value as integer list, with potential conversion.

operator const std::vector<GIntBig>&()const

Return the field value as 64-bit integer list, with potential conversion.

operator const std::vector<double>&()const

Return the field value as double list, with potential conversion.

operator const std::vector<std::string>&()const

Return the field value as string list, with potential conversion.

operator CSLConstList()const

Return the field value as string list, with potential conversion.

int GetAsInteger()const

Return the field value as integer, with potential conversion.

GIntBigGetAsInteger64()const

Return the field value as 64-bit integer, with potential conversion.

double GetAsDouble()const

Return the field value as double, with potential conversion.

const char *GetAsString()const

Return the field value as string, with potential conversion.

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

Return the field value as integer list, with potential conversion.

const std::vector<GIntBig> &GetAsInteger64List()const

Return the field value as 64-bit integer list, with potential conversion.

const std::vector<double> &GetAsDoubleList()const

Return the field value as double list, with potential conversion.

const std::vector<std::string> &GetAsStringList()const

Return the field value as string list, with potential conversion.

structPrivate

OGRFeatureDefn类

classOGRFeatureDefn

Definition of a feature class or feature layer.

This object contains schema information for a set of OGRFeatures. In table based systems, an OGRFeatureDefn is essentially a layer. In more object oriented approaches (such as SF CORBA) this can represent a class of features but doesn't necessarily relate to all of a layer, or just one layer.

This object also can contain some other information such as a name and potentially other metadata.

It is essentially a collection of field descriptions (OGRFieldDefn class). Starting with GDAL 1.11, in addition to attribute fields, it can also contain multiple geometry fields (OGRGeomFieldDefn class).

It is reasonable for different translators to derive classes from OGRFeatureDefn with additional translator specific information.

公共职能

OGRFeatureDefn(const char *pszName = nullptr)

Constructor.

The OGRFeatureDefn maintains a reference count, but this starts at zero. It is mainly intended to represent a count of OGRFeature's based on this definition.

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

Parameters

pszName: the name to be assigned to this layer/class. It does not need to be unique.

void SetName(const char *pszName)

Change name of this OGRFeatureDefn.

Since

GDAL 2.3

Parameters

pszName: feature definition name

const char *GetName()const

Get name of this OGRFeatureDefn.

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

Return

the name. This name is internal and should not be modified, or freed.

int GetFieldCount()const

Fetch number of fields on this feature.

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

Return

count of fields.

OGRFieldDefn *GetFieldDefn(int i)

Fetch field definition.

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

Return

a pointer to an internal field definition object or NULL if invalid index. This object should not be modified or freed by the application.

Parameters

iField: the field to fetch, between 0 and GetFieldCount() - 1.

constOGRFieldDefn *GetFieldDefn(int i)const

Fetch field definition.

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

Return

a pointer to an internal field definition object or NULL if invalid index. This object should not be modified or freed by the application.

Since

GDAL 2.3

Parameters

iField: the field to fetch, between 0 and GetFieldCount() - 1.

int GetFieldIndex(const char*)const

Find field by name.

The field index of the first field matching the passed field name (case insensitively) is returned.

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

Return

the field index, or -1 if no match found.

Parameters

pszFieldName: the field name to search for.

int GetFieldIndexCaseSensitive(const char*)const

Find field by name, in a case sensitive way.

The field index of the first field matching the passed field name is returned.

Return

the field index, or -1 if no match found.

Parameters

pszFieldName: the field name to search for.

void AddFieldDefn(OGRFieldDefn*)

Add a new field definition.

To add a new field definition to a layer definition, do not use this function directly, but use OGRLayer::CreateField() instead.

This method should only be called while there are no OGRFeature objects in existence based on this OGRFeatureDefn. The OGRFieldDefn passed in is copied, and remains the responsibility of the caller.

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

Parameters

poNewDefn: the definition of the new field.

OGRErrDeleteFieldDefn(int iField)

Delete an existing field definition.

To delete an existing field definition from a layer definition, do not use this function directly, but use OGRLayer::DeleteField() instead.

This method should only be called while there are no OGRFeature objects in existence based on this OGRFeatureDefn.

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

Return

OGRERR_NONE in case of success.

Since

OGR 1.9.0

Parameters

iField: the index of the field definition.

OGRErrReorderFieldDefns(int *panMap)

Reorder the field definitions in the array of the feature definition.

To reorder the field definitions in a layer definition, do not use this function directly, but use OGR_L_ReorderFields() instead.

This method should only be called while there are no OGRFeature objects in existence based on this OGRFeatureDefn.

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

Return

OGRERR_NONE in case of success.

Since

OGR 1.9.0

Parameters

panMap: an array of GetFieldCount() elements which is a permutation of [0, GetFieldCount()-1]. panMap is such that, for each field definition at position i after reordering, its position before reordering was panMap[i].

int GetGeomFieldCount()const

Fetch number of geometry fields on this feature.

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

Return

count of geometry fields.

Since

GDAL 1.11

OGRGeomFieldDefn *GetGeomFieldDefn(int i)

Fetch geometry field definition.

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

Return

a pointer to an internal field definition object or NULL if invalid index. This object should not be modified or freed by the application.

Since

GDAL 1.11

Parameters

iGeomField: the geometry field to fetch, between 0 and GetGeomFieldCount() - 1.

constOGRGeomFieldDefn *GetGeomFieldDefn(int i)const

Fetch geometry field definition.

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

Return

a pointer to an internal field definition object or NULL if invalid index. This object should not be modified or freed by the application.

Since

GDAL 2.3

Parameters

iGeomField: the geometry field to fetch, between 0 and GetGeomFieldCount() - 1.

int GetGeomFieldIndex(const char*)const

Find geometry field by name.

The geometry field index of the first geometry field matching the passed field name (case insensitively) is returned.

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

Return

the geometry field index, or -1 if no match found.

Parameters

pszGeomFieldName: the geometry field name to search for.

void AddGeomFieldDefn(OGRGeomFieldDefn*, int bCopy = TRUE)

Add a new geometry field definition.

To add a new geometry field definition to a layer definition, do not use this function directly, but use OGRLayer::CreateGeomField() instead.

This method does an internal copy of the passed geometry field definition, unless bCopy is set to FALSE (in which case it takes ownership of the field definition.

This method should only be called while there are no OGRFeature objects in existence based on this OGRFeatureDefn. The OGRGeomFieldDefn passed in is copied, and remains the responsibility of the caller.

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

Since

GDAL 1.11

Parameters

poNewDefn: the definition of the new geometry field.
bCopy: whether poNewDefn should be copied.

OGRErrDeleteGeomFieldDefn(int iGeomField)

Delete an existing geometry field definition.

To delete an existing field definition from a layer definition, do not use this function directly, but use OGRLayer::DeleteGeomField() instead.

This method should only be called while there are no OGRFeature objects in existence based on this OGRFeatureDefn.

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

Return

OGRERR_NONE in case of success.

Since

GDAL 1.11

Parameters

iGeomField: the index of the geometry field definition.

OGRwkbGeometryTypeGetGeomType()const

Fetch the geometry base type.

Note that some drivers are unable to determine a specific geometry type for a layer, in which case wkbUnknown is returned. A value of wkbNone indicates no geometry is available for the layer at all. Many drivers do not properly mark the geometry type as 25D even if some or all geometries are in fact 25D. A few (broken) drivers return wkbPolygon for layers that also include wkbMultiPolygon.

Starting with GDAL 1.11, this method returns GetGeomFieldDefn(0)->GetType().

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

Return

the base type for all geometry related to this definition.

void SetGeomType(OGRwkbGeometryType)

Assign the base geometry type for this layer.

All geometry objects using this type must be of the defined type or a derived type. The default upon creation is wkbUnknown which allows for any geometry type. The geometry type should generally not be changed after any OGRFeatures have been created against this definition.

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

Starting with GDAL 1.11, this method calls GetGeomFieldDefn(0)->SetType().

Parameters

eNewType: the new type to assign.

OGRFeatureDefn *Clone()const

Create a copy of this feature definition.

Creates a deep copy of the feature definition.

Return

the copy.

int Reference()

Increments the reference count by one.

The reference count is used keep track of the number of OGRFeature objects referencing this definition.

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

Return

the updated reference count.

int Dereference()

Decrements the reference count by one.

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

Return

the updated reference count.

int GetReferenceCount()const

Fetch current reference count.

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

Return

the current reference count.

void Release()

Drop a reference to this object, and destroy if no longer referenced.

int IsGeometryIgnored()const

Determine whether the geometry can be omitted when fetching features.

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

Starting with GDAL 1.11, this method returns GetGeomFieldDefn(0)->IsIgnored().

Return

ignore state

void SetGeometryIgnored(int bIgnore)

Set whether the geometry can be omitted when fetching features.

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

Starting with GDAL 1.11, this method calls GetGeomFieldDefn(0)->SetIgnored().

Parameters

bIgnore: ignore state

int IsStyleIgnored()const

Determine whether the style can be omitted when fetching features.

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

Return

ignore state

void SetStyleIgnored(int bIgnore)

Set whether the style can be omitted when fetching features.

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

Parameters

bIgnore: ignore state

int IsSame(constOGRFeatureDefn *poOtherFeatureDefn)const

Test if the feature definition is identical to the other one.

Return

TRUE if the feature definition is identical to the other one.

Parameters

poOtherFeatureDefn: the other feature definition to compare to.

std::vector<int> ComputeMapForSetFrom(constOGRFeatureDefn *poSrcFDefn, bool bForgiving = true)const

Compute the map from source to target field that can be passed to SetFrom().

Return

an array of size poSrcFDefn->GetFieldCount() if everything succeeds, or empty in case a source field definition was not found in the target layer and bForgiving == true.

Since

GDAL 2.3

Parameters

poSrcFDefn: the feature definition of source features later passed to SetFrom()
bForgiving: true if the operation should continue despite lacking output fields matching some of the source fields.

公共静态函数

OGRFeatureDefn *CreateFeatureDefn(const char *pszName = nullptr)

Create a new feature definition object.

Return

new feature definition object.

Parameters

pszName: name

void DestroyFeatureDefn(OGRFeatureDefn*)

Destroy a feature definition.

Parameters

poDefn: feature definition.

OGRFeatureDefnHToHandle(OGRFeatureDefn *poFeatureDefn)

Convert a OGRFeatureDefn* to a OGRFeatureDefnH.

Since

GDAL 2.3

OGRFeatureDefn *FromHandle(OGRFeatureDefnHhFeatureDefn)

Convert a OGRFeatureDefnH to a OGRFeatureDefn*.

Since

GDAL 2.3

OGRFieldDefn类

classOGRFieldDefn

Definition of an attribute of an OGRFeatureDefn.

A field is described by :

a name. See SetName() / GetNameRef()
an alternative name (optional): alternative descriptive name for the field (sometimes referred to as an "alias"). See SetAlternativeName() / GetAlternativeNameRef()
a type: OFTString, OFTInteger, OFTReal, ... See SetType() / GetType()
a subtype (optional): OFSTBoolean, ... See SetSubType() / GetSubType()
a width (optional): maximal number of characters. See SetWidth() / GetWidth()
a precision (optional): number of digits after decimal point. See SetPrecision() / GetPrecision()
a NOT NULL constraint (optional). See SetNullable() / IsNullable()
a UNIQUE constraint (optional). See SetUnique() / IsUnique()
a default value (optional). See SetDefault() / GetDefault()
a boolean to indicate whether it should be ignored when retrieving features. See SetIgnored() / IsIgnored()

公共职能

OGRFieldDefn(const char*, OGRFieldType)

Constructor.

By default, fields have no width, precision, are nullable and not ignored.

Parameters

pszNameIn: the name of the new field.
eTypeIn: the type of the new field.

OGRFieldDefn(constOGRFieldDefn*)

Constructor.

Create by cloning an existing field definition.

Parameters

poPrototype: the field definition to clone.

void SetName(const char*)

Reset the name of this field.

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

Parameters

pszNameIn: the new name to apply.

const char *GetNameRef()const

Fetch name of this field.

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

Return

pointer to an internal name string that should not be freed or modified.

void SetAlternativeName(const char*)

Reset the alternative name (or "alias") for this field.

The alternative name is an optional attribute for a field which can provide a more user-friendly, descriptive name of a field which is not subject to the usual naming constraints defined by the data provider.

This is a metadata style attribute only: the alternative name cannot be used in place of the actual field name during SQL queries or other field name dependent API calls.

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

Since

GDAL 3.2

Parameters

pszAlternativeNameIn: the new alternative name to apply.

const char *GetAlternativeNameRef()const

Fetch the alternative name (or "alias") for this field.

This is a metadata style attribute only: the alternative name cannot be used in place of the actual field name during SQL queries or other field name dependent API calls.

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

Return

pointer to an internal alternative name string that should not be freed or modified.

Since

GDAL 3.2

OGRFieldTypeGetType()const

Fetch type of this field.

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

Return

field type.

void SetType(OGRFieldTypeeTypeIn)

Set the type of this field.

This should never be done to an OGRFieldDefn that is already part of an OGRFeatureDefn.

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

Parameters

eTypeIn: the new field type.

OGRFieldSubTypeGetSubType()const

Fetch subtype of this field.

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

Return

field subtype.

Since

GDAL 2.0

void SetSubType(OGRFieldSubTypeeSubTypeIn)

Set the subtype of this field.

This should never be done to an OGRFieldDefn that is already part of an OGRFeatureDefn.

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

Since

GDAL 2.0

Parameters

eSubTypeIn: the new field subtype.

OGRJustificationGetJustify()const

Get the justification for this field.

Note: no driver is know to use the concept of field justification.

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

Return

the justification.

void SetJustify(OGRJustificationeJustifyIn)

Set the justification for this field.

Note: no driver is know to use the concept of field justification.

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

Parameters

eJustify: the new justification.

int GetWidth()const

Get the formatting width for this field.

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

Return

the width, zero means no specified width.

void SetWidth(int nWidthIn)

Set the formatting width for this field in characters.

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

Parameters

nWidth: the new width.

int GetPrecision()const

Get the formatting precision for this field. This should normally be zero for fields of types other than OFTReal.

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

Return

the precision.

void SetPrecision(int nPrecisionIn)

Set the formatting precision for this field in characters.

This should normally be zero for fields of types other than OFTReal.

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

Parameters

nPrecision: the new precision.

void Set(const char*, OGRFieldType, int = 0, int = 0, OGRJustification = OJUndefined)

Set defining parameters for a field in one call.

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

Parameters

pszNameIn: the new name to assign.
eTypeIn: the new type (one of the OFT values like OFTInteger).
nWidthIn: the preferred formatting width. Defaults to zero indicating undefined.
nPrecisionIn: number of decimals places for formatting, defaults to zero indicating undefined.
eJustifyIn: the formatting justification (OJLeft or OJRight), defaults to OJUndefined.

void SetDefault(const char*)

Set default field value.

The default field value is taken into account by drivers (generally those with a SQL interface) that support it at field creation time. OGR will generally not automatically set the default field value to null fields by itself when calling OGRFeature::CreateFeature() / OGRFeature::SetFeature(), but will let the low-level layers to do the job. So retrieving the feature from the layer is recommended.

The accepted values are NULL, a numeric value, a literal value enclosed between single quote characters (and inner single quote characters escaped by repetition of the single quote character), CURRENT_TIMESTAMP, CURRENT_TIME, CURRENT_DATE or a driver specific expression (that might be ignored by other drivers). For a datetime literal value, format should be 'YYYY/MM/DD HH:MM:SS[.sss]' (considered as UTC time).

Drivers that support writing DEFAULT clauses will advertise the GDAL_DCAP_DEFAULT_FIELDS driver metadata item.

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

Since

GDAL 2.0

Parameters

pszDefaultIn: new default field value or NULL pointer.

const char *GetDefault()const

Get default field value.

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

Return

default field value or NULL.

Since

GDAL 2.0

int IsDefaultDriverSpecific()const

Returns whether the default value is driver specific.

Driver specific default values are those that are not NULL, a numeric value, a literal value enclosed between single quote characters, CURRENT_TIMESTAMP, CURRENT_TIME, CURRENT_DATE or datetime literal value.

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

Return

TRUE if the default value is driver specific.

Since

GDAL 2.0

int IsIgnored()const

Return whether this field should be omitted when fetching features.

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

Return

ignore state

void SetIgnored(int bIgnoreIn)

Set whether this field should be omitted when fetching features.

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

Parameters

ignore: ignore state

int IsNullable()const

Return whether this field can receive null values.

By default, fields are nullable.

Even if this method returns FALSE (i.e not-nullable field), it doesn't mean that OGRFeature::IsFieldSet() will necessary return TRUE, as fields can be temporary unset and null/not-null validation is usually done when OGRLayer::CreateFeature()/SetFeature() is called.

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

Return

TRUE if the field is authorized to be null.

Since

GDAL 2.0

void SetNullable(int bNullableIn)

Set whether this field can receive null values.

By default, fields are nullable, so this method is generally called with FALSE to set a not-null constraint.

Drivers that support writing not-null constraint will advertise the GDAL_DCAP_NOTNULL_FIELDS driver metadata item.

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

Since

GDAL 2.0

Parameters

bNullableIn: FALSE if the field must have a not-null constraint.

int IsUnique()const

Return whether this field has a unique constraint.

By default, fields have no unique constraint.

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

Return

TRUE if the field has a unique constraint.

Since

GDAL 3.2

void SetUnique(int bUniqueIn)

Set whether this field has a unique constraint.

By default, fields have no unique constraint, so this method is generally called with TRUE to set a unique constraint.

Drivers that support writing unique constraint will advertise the GDAL_DCAP_UNIQUE_FIELDS driver metadata item.

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

Since

GDAL 3.2

Parameters

bUniqueIn: TRUE if the field must have a unique constraint.

int IsSame(constOGRFieldDefn*)const

Test if the field definition is identical to the other one.

Return

TRUE if the field definition is identical to the other one.

Parameters

poOtherFieldDefn: the other field definition to compare to.

公共静态函数

const char *GetFieldTypeName(OGRFieldType)

Fetch human readable name for a field type.

This static method is the same as the C function OGR_GetFieldTypeName().

Return

pointer to an internal static name string. It should not be modified or freed.

Parameters

eType: the field type to get name for.

const char *GetFieldSubTypeName(OGRFieldSubType)

Fetch human readable name for a field subtype.

This static method is the same as the C function OGR_GetFieldSubTypeName().

Return

pointer to an internal static name string. It should not be modified or freed.

Since

GDAL 2.0

Parameters

eSubType: the field subtype to get name for.

OGRFieldDefnHToHandle(OGRFieldDefn *poFieldDefn)

Convert a OGRFieldDefn* to a OGRFieldDefnH.

Since

GDAL 2.3

OGRFieldDefn *FromHandle(OGRFieldDefnHhFieldDefn)

Convert a OGRFieldDefnH to a OGRFieldDefn*.

Since

GDAL 2.3

ogrgeomfieldefn类

classOGRGeomFieldDefn

Definition of a geometry field of an OGRFeatureDefn.

A geometry field is described by :

a name. See SetName() / GetNameRef()
a type: wkbPoint, wkbLineString, ... See SetType() / GetType()
a spatial reference system (optional). See SetSpatialRef() / GetSpatialRef()
a NOT NULL constraint (optional). See SetNullable() / IsNullable()
a boolean to indicate whether it should be ignored when retrieving features. See SetIgnored() / IsIgnored()

Since

OGR 1.11

公共职能

OGRGeomFieldDefn(const char *pszNameIn, OGRwkbGeometryTypeeGeomTypeIn)

Constructor.

Since

GDAL 1.11

Parameters

pszNameIn: the name of the new field.
eGeomTypeIn: the type of the new field.

OGRGeomFieldDefn(constOGRGeomFieldDefn*)

Constructor.

Create by cloning an existing geometry field definition.

Since

GDAL 1.11

Parameters

poPrototype: the geometry field definition to clone.

void SetName(const char*)

Reset the name of this field.

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

Since

GDAL 1.11

Parameters

pszNameIn: the new name to apply.

const char *GetNameRef()const

Fetch name of this field.

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

Return

pointer to an internal name string that should not be freed or modified.

Since

GDAL 1.11

OGRwkbGeometryTypeGetType()const

Fetch geometry type of this field.

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

Return

field geometry type.

Since

GDAL 1.11

void SetType(OGRwkbGeometryTypeeTypeIn)

Set the geometry type of this field.

This should never be done to an OGRGeomFieldDefn that is already part of an OGRFeatureDefn.

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

Since

GDAL 1.11

Parameters

eTypeIn: the new field geometry type.

OGRSpatialReference *GetSpatialRef()const

Fetch spatial reference system of this field.

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

Return

field spatial reference system.

Since

GDAL 1.11

void SetSpatialRef(OGRSpatialReference *poSRSIn)

Set the spatial reference of this field.

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

This method drops the reference of the previously set SRS object and acquires a new reference on the passed object (if non-NULL).

Since

GDAL 1.11

Parameters

poSRSIn: the new SRS to apply.

int IsIgnored()const

Return whether this field should be omitted when fetching features.

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

Return

ignore state

Since

GDAL 1.11

void SetIgnored(int bIgnoreIn)

Set whether this field should be omitted when fetching features.

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

Since

GDAL 1.11

Parameters

ignore: ignore state

int IsNullable()const

Return whether this geometry field can receive null values.

By default, fields are nullable.

Note that not-nullable geometry fields might also contain 'empty' geometries.

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

Return

TRUE if the field is authorized to be null.

Since

GDAL 2.0

void SetNullable(int bNullableIn)

Set whether this geometry field can receive null values.

By default, fields are nullable, so this method is generally called with FALSE to set a not-null constraint.

Drivers that support writing not-null constraint will advertise the GDAL_DCAP_NOTNULL_GEOMFIELDS driver metadata item.

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

Since

GDAL 2.0

Parameters

bNullableIn: FALSE if the field must have a not-null constraint.

int IsSame(constOGRGeomFieldDefn*)const

Test if the geometry field definition is identical to the other one.

Return

TRUE if the geometry field definition is identical to the other one.

Since

GDAL 1.11

Parameters

poOtherFieldDefn: the other field definition to compare to.

公共静态函数

OGRGeomFieldDefnHToHandle(OGRGeomFieldDefn *poGeomFieldDefn)

Convert a OGRGeomFieldDefn* to a OGRGeomFieldDefnH.

Since

GDAL 2.3

OGRGeomFieldDefn *FromHandle(OGRGeomFieldDefnHhGeomFieldDefn)

Convert a OGRGeomFieldDefnH to a OGRGeomFieldDefn*.

Since

GDAL 2.3

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OGRFeature类

OGReMeC++ C++ API

OGRFeature类

OGRFeatureDefn类

OGRFieldDefn类

ogrgeomfieldefn类

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