A structured metadata store for a map layer. More...

#include <qgslayermetadata.h>

Inheritance diagram for QgsLayerMetadata:

[legend]

Classes
struct	Constraint
	Metadata constraint structure. More...
struct	Extent
	Metadata extent structure. More...
struct	SpatialExtent
	Metadata spatial extent structure. More...

Public Types
typedef QList< QgsLayerMetadata::Constraint >	ConstraintList
	A list of constraints.
Public Types inherited from QgsAbstractMetadataBase
typedef QList< QgsAbstractMetadataBase::Contact >	ContactList
	A list of contacts.
typedef QMap< QString, QStringList >	KeywordMap
	Map of vocabulary string to keyword list.
typedef QList< QgsAbstractMetadataBase::Link >	LinkList
	A list of links.

Public Member Functions
	QgsLayerMetadata ()=default
void	addConstraint (const QgsLayerMetadata::Constraint &constraint)
	Adds an individual constraint to the existing constraints.
QgsLayerMetadata *	clone () const override
	Clones the metadata object.
void	combine (const QgsAbstractMetadataBase *other) override
	Combines the metadata from this object with the metadata from an other object.
QgsLayerMetadata::ConstraintList	constraints () const
	Returns a list of constraints associated with using the resource.
bool	contains (const QString &searchString) const
	Returns `true` if the metadata identifier, title, abstract, keywords or categories contain searchString using case-insensitive search.
QgsCoordinateReferenceSystem	crs () const
	Returns the coordinate reference system described by the layer's metadata.
QString	encoding () const
	Returns the character encoding of the data in the resource.
QgsLayerMetadata::Extent &	extent ()
	Returns the spatial and temporal extents associated with the resource.
const QgsLayerMetadata::Extent &	extent () const
	Returns the spatial and temporal extents associated with the resource.
QString	fees () const
	Returns any fees associated with using the resource.
QStringList	licenses () const
	Returns a list of licenses associated with the resource (examples: http://opendefinition.org/licenses/).
bool	matches (const QVector< QRegularExpression > &searchReList) const
	Returns `true` if the metadata identifier, title, abstract, keywords or categories matches any regular expression from searchReList.
bool	operator== (const QgsLayerMetadata &metadataOther) const
void	readFromLayer (const QgsMapLayer *layer)
	Reads the metadata state from a layer's custom properties (see QgsMapLayer::customProperty() ).
bool	readMetadataXml (const QDomElement &metadataElement, const QgsReadWriteContext &context=QgsReadWriteContext()) override
	Sets state from DOM document.
void	registerTranslations (QgsTranslationContext *translationContext) const override
	Registers metadata translation strings.
QStringList	rights () const
	Returns a list of attribution or copyright strings associated with the resource.
void	saveToLayer (QgsMapLayer *layer) const
	Saves the metadata to a layer's custom properties (see QgsMapLayer::setCustomProperty() ).
void	setConstraints (const QgsLayerMetadata::ConstraintList &constraints)
	Sets the list of constraints associated with using the resource.
void	setCrs (const QgsCoordinateReferenceSystem &crs)
	Sets the coordinate reference system for the layer's metadata.
void	setEncoding (const QString &encoding)
	Sets the character encoding of the data in the resource.
void	setExtent (const QgsLayerMetadata::Extent &extent)
	Sets the spatial and temporal extents associated with the resource.
void	setFees (const QString &fees)
	Sets the fees associated with using the resource.
void	setLicenses (const QStringList &licenses)
	Sets a list of licenses associated with the resource.
void	setRights (const QStringList &rights)
	Sets a list of rights (attribution or copyright strings) associated with the resource.
bool	writeMetadataXml (QDomElement &metadataElement, QDomDocument &document, const QgsReadWriteContext &context=QgsReadWriteContext()) const override
	Stores state in a DOM node.
Public Member Functions inherited from QgsAbstractMetadataBase
virtual	~QgsAbstractMetadataBase ()=default
QString	abstract () const
	Returns a free-form description of the resource.
void	addContact (const QgsAbstractMetadataBase::Contact &contact)
	Adds an individual contact to the existing contacts.
void	addHistoryItem (const QString &text)
	Adds a single history text to the end of the existing history list.
void	addKeywords (const QString &vocabulary, const QStringList &keywords)
	Adds a list of descriptive keywords for a specified vocabulary.
void	addLink (const QgsAbstractMetadataBase::Link &link)
	Adds an individual link to the existing links.
QStringList	categories () const
	Returns categories of the resource.
QgsAbstractMetadataBase::ContactList	contacts () const
	Returns a list of contact persons or entities associated with the resource.
QDateTime	dateTime (Qgis::MetadataDateType type) const
	Returns the date for the specified date type.
QStringList	history () const
	Returns a freeform description of the history or lineage of the resource.
QString	identifier () const
	A reference, URI, URL or some other mechanism to identify the resource.
QgsAbstractMetadataBase::KeywordMap	keywords () const
	Returns the keywords map, which is a set of descriptive keywords associated with the resource.
QStringList	keywords (const QString &vocabulary) const
	Returns a list of keywords for the specified vocabulary.
QStringList	keywordVocabularies () const
	Returns a list of keyword vocabularies contained in the metadata.
QString	language () const
	Returns the human language associated with the resource.
QgsAbstractMetadataBase::LinkList	links () const
	Returns a list of online resources associated with the resource.
QString	parentIdentifier () const
	A reference, URI, URL or some other mechanism to identify the parent resource that this resource is a part (child) of.
bool	removeKeywords (const QString &vocabulary)
	Remove a vocabulary from the list.
void	setAbstract (const QString &abstract)
	Sets a free-form abstract (description) of the resource.
void	setCategories (const QStringList &categories)
	Sets categories of the resource.
void	setContacts (const QgsAbstractMetadataBase::ContactList &contacts)
	Sets the list of contacts or entities associated with the resource.
void	setDateTime (Qgis::MetadataDateType type, QDateTime date)
	Sets a date value for the specified date type.
void	setHistory (const QStringList &history)
	Sets the freeform description of the history or lineage of the resource.
void	setIdentifier (const QString &identifier)
	Sets the reference, URI, URL or some other mechanism to identify the resource.
void	setKeywords (const QgsAbstractMetadataBase::KeywordMap &keywords)
	Sets the keywords map, which is a set of descriptive keywords associated with the resource.
void	setLanguage (const QString &language)
	Sets the human language associated with the resource.
void	setLinks (const QgsAbstractMetadataBase::LinkList &links)
	Sets the list of online resources associated with the resource.
void	setParentIdentifier (const QString &parentIdentifier)
	Sets a reference, URI, URL or some other mechanism to identify the parent resource that this resource is a part (child) of.
void	setTitle (const QString &title)
	Sets the human readable title (name) of the resource, typically displayed in search results.
void	setType (const QString &type)
	Sets the type (nature) of the resource.
QString	title () const
	Returns the human readable name of the resource, typically displayed in search results.
QString	type () const
	Returns the nature of the resource.

Additional Inherited Members
Protected Member Functions inherited from QgsAbstractMetadataBase
	QgsAbstractMetadataBase ()=default
	Constructor for QgsAbstractMetadataBase.
bool	equals (const QgsAbstractMetadataBase &other) const
	Tests whether the common metadata fields in this object are equal to other.
Protected Attributes inherited from QgsAbstractMetadataBase
QString	mAbstract
QgsAbstractMetadataBase::ContactList	mContacts
QMap< Qgis::MetadataDateType, QDateTime >	mDates
	Metadata dates.
QStringList	mHistory
QString	mIdentifier
QgsAbstractMetadataBase::KeywordMap	mKeywords
	Keywords map.
QString	mLanguage
QgsAbstractMetadataBase::LinkList	mLinks
QString	mParentIdentifier
QString	mTitle
QString	mType

Detailed Description

A structured metadata store for a map layer.

QgsLayerMetadata handles storage and management of the metadata for a QgsMapLayer. This class is an internal QGIS format with a common metadata structure, which allows for code to access the metadata properties for layers in a uniform way.

The metadata store is designed to be compatible with the Dublin Core metadata specifications, and will be expanded to allow compatibility with ISO specifications in future releases. However, the QGIS internal schema does not represent a superset of all existing metadata schemas and accordingly conversion from specific metadata formats to QgsLayerMetadata may result in a loss of information.

This class is designed to follow the specifications detailed in the schema definition available at resources/qgis-resource-metadata.xsd within the QGIS source code.

Metadata can be validated through the use of QgsLayerMetadataValidator subclasses. E.g. validating against the native QGIS metadata schema can be performed using QgsNativeMetadataValidator.

Definition at line 55 of file qgslayermetadata.h.

Member Typedef Documentation

◆ ConstraintList

typedef QList< QgsLayerMetadata::Constraint > QgsLayerMetadata::ConstraintList

A list of constraints.

Definition at line 167 of file qgslayermetadata.h.

Constructor & Destructor Documentation

◆ QgsLayerMetadata()

QgsLayerMetadata::QgsLayerMetadata ( )

default

Member Function Documentation

◆ addConstraint()

void QgsLayerMetadata::addConstraint ( const QgsLayerMetadata::Constraint & constraint )

Adds an individual constraint to the existing constraints.

See also: constraints(); setConstraints()

Definition at line 40 of file qgslayermetadata.cpp.

◆ clone()

QgsLayerMetadata * QgsLayerMetadata::clone ( ) const

overridevirtual

Clones the metadata object.

Since: QGIS 3.2

Implements QgsAbstractMetadataBase.

Definition at line 25 of file qgslayermetadata.cpp.

◆ combine()

void QgsLayerMetadata::combine ( const QgsAbstractMetadataBase * other )

overridevirtual

Combines the metadata from this object with the metadata from an other object.

Any existing values in this object will be overwritten by non-empty values from other.

Since: QGIS 3.20

Reimplemented from QgsAbstractMetadataBase.

Definition at line 359 of file qgslayermetadata.cpp.

◆ constraints()

QList< QgsLayerMetadata::Constraint > QgsLayerMetadata::constraints ( ) const

Returns a list of constraints associated with using the resource.

See also: setConstraints()

Definition at line 45 of file qgslayermetadata.cpp.

◆ contains()

bool QgsLayerMetadata::contains ( const QString & searchString ) const

Returns true if the metadata identifier, title, abstract, keywords or categories contain searchString using case-insensitive search.

If searchString is empty this method returns false.

Since: QGIS 3.28

Definition at line 443 of file qgslayermetadata.cpp.

◆ crs()

QgsCoordinateReferenceSystem QgsLayerMetadata::crs ( ) const

Returns the coordinate reference system described by the layer's metadata.

Note that this has no link to QgsMapLayer::crs(). While in most cases these two systems are likely to be identical, it is possible to have a layer with a different CRS described by it's accompanying metadata versus the CRS which is actually used to display and manipulate the layer within QGIS. This may be the case when a layer has an incorrect CRS within its metadata and a user has manually overridden the layer's CRS within QGIS.

The CRS described here should either match the CRS from the layer QgsMapLayer::crs() or the CRS from the data provider.

This property should also match the CRS property used in the spatial extent.

See also: setCrs()

Definition at line 85 of file qgslayermetadata.cpp.

◆ encoding()

QString QgsLayerMetadata::encoding ( ) const

Returns the character encoding of the data in the resource.

An empty string will be returned if no encoding is set.

See also: setEncoding()

Definition at line 75 of file qgslayermetadata.cpp.

◆ extent() [1/2]

QgsLayerMetadata::Extent & QgsLayerMetadata::extent ( )

Returns the spatial and temporal extents associated with the resource.

See also: setExtent()

Definition at line 396 of file qgslayermetadata.cpp.

◆ extent() [2/2]

const QgsLayerMetadata::Extent & QgsLayerMetadata::extent ( ) const

Returns the spatial and temporal extents associated with the resource.

See also: setExtent()

Definition at line 391 of file qgslayermetadata.cpp.

◆ fees()

QString QgsLayerMetadata::fees ( ) const

Returns any fees associated with using the resource.

An empty string will be returned if no fees are set.

See also: setFees()

Definition at line 30 of file qgslayermetadata.cpp.

◆ licenses()

QStringList QgsLayerMetadata::licenses ( ) const

Returns a list of licenses associated with the resource (examples: http://opendefinition.org/licenses/).

See also: setLicenses()

Definition at line 65 of file qgslayermetadata.cpp.

◆ matches()

bool QgsLayerMetadata::matches ( const QVector< QRegularExpression > & searchReList ) const

Returns true if the metadata identifier, title, abstract, keywords or categories matches any regular expression from searchReList.

Since: QGIS 3.28

Definition at line 482 of file qgslayermetadata.cpp.

◆ operator==()

bool QgsLayerMetadata::operator== ( const QgsLayerMetadata & metadataOther ) const

Definition at line 431 of file qgslayermetadata.cpp.

◆ readFromLayer()

void QgsLayerMetadata::readFromLayer ( const QgsMapLayer * layer )

Reads the metadata state from a layer's custom properties (see QgsMapLayer::customProperty() ).

See also: saveToLayer()

Definition at line 116 of file qgslayermetadata.cpp.

◆ readMetadataXml()

bool QgsLayerMetadata::readMetadataXml	(	const QDomElement &	metadataElement,
		const QgsReadWriteContext &	context = QgsReadWriteContext() )

overridevirtual

Sets state from DOM document.

Parameters

metadataElement	The DOM element corresponding to resourceMetadata tag
context	The context object to handle project translation (since QGIS 4.0)

Returns: true if successful

Subclasses which override this method should take care to also call the base class method in order to read common metadata properties.

Reimplemented from QgsAbstractMetadataBase.

Definition at line 138 of file qgslayermetadata.cpp.

◆ registerTranslations()

void QgsLayerMetadata::registerTranslations ( QgsTranslationContext * translationContext ) const

overridevirtual

Registers metadata translation strings.

Since: QGIS 4.0

Reimplemented from QgsAbstractMetadataBase.

Definition at line 349 of file qgslayermetadata.cpp.

◆ rights()

QStringList QgsLayerMetadata::rights ( ) const

Returns a list of attribution or copyright strings associated with the resource.

See also: setRights()

Definition at line 55 of file qgslayermetadata.cpp.

◆ saveToLayer()

void QgsLayerMetadata::saveToLayer ( QgsMapLayer * layer ) const

Saves the metadata to a layer's custom properties (see QgsMapLayer::setCustomProperty() ).

See also: readFromLayer()

Definition at line 95 of file qgslayermetadata.cpp.

◆ setConstraints()

void QgsLayerMetadata::setConstraints ( const QgsLayerMetadata::ConstraintList & constraints )

Sets the list of constraints associated with using the resource.

See also: constraints()

Definition at line 50 of file qgslayermetadata.cpp.

◆ setCrs()

void QgsLayerMetadata::setCrs ( const QgsCoordinateReferenceSystem & crs )

Sets the coordinate reference system for the layer's metadata.

Note that this has no link to QgsMapLayer::setCrs(). Setting the layer's CRS via QgsMapLayer::setCrs() does not affect the layer's metadata CRS, and changing the CRS from the metadata will not change the layer's CRS or how it is projected within QGIS.

While ideally these two systems are likely to be identical, it is possible to have a layer with a different CRS described by it's accompanying metadata versus the CRS which is actually used to display and manipulate the layer within QGIS. This may be the case when a layer has an incorrect CRS within its metadata and a user has manually overridden the layer's CRS within QGIS.

The CRS described here should either match the CRS from the layer QgsMapLayer::crs() or the CRS from the data provider.

This property should also match the CRS property used in the spatial extent.

See also: crs()

Definition at line 90 of file qgslayermetadata.cpp.

◆ setEncoding()

void QgsLayerMetadata::setEncoding ( const QString & encoding )

Sets the character encoding of the data in the resource.

Use an empty string if no encoding is set.

See also: encoding()

Definition at line 80 of file qgslayermetadata.cpp.

◆ setExtent()

void QgsLayerMetadata::setExtent ( const QgsLayerMetadata::Extent & extent )

Sets the spatial and temporal extents associated with the resource.

See also: setExtent()

Definition at line 401 of file qgslayermetadata.cpp.

◆ setFees()

void QgsLayerMetadata::setFees ( const QString & fees )

Sets the fees associated with using the resource.

Use an empty string if no fees are set.

See also: fees()

Definition at line 35 of file qgslayermetadata.cpp.

◆ setLicenses()

void QgsLayerMetadata::setLicenses ( const QStringList & licenses )

Sets a list of licenses associated with the resource.

(examples: http://opendefinition.org/licenses/).

See also: licenses()

Definition at line 70 of file qgslayermetadata.cpp.

◆ setRights()

void QgsLayerMetadata::setRights ( const QStringList & rights )

Sets a list of rights (attribution or copyright strings) associated with the resource.

See also: rights()

Definition at line 60 of file qgslayermetadata.cpp.

◆ writeMetadataXml()

bool QgsLayerMetadata::writeMetadataXml	(	QDomElement &	metadataElement,
		QDomDocument &	document,
		const QgsReadWriteContext &	context = QgsReadWriteContext() ) const

overridevirtual

Stores state in a DOM node.

Parameters

metadataElement	is a DOM element corresponding to resourceMetadata tag
document	is a the DOM document being written
context	The context object to handle project translation (since QGIS 4.0)

Returns: true if successful

Subclasses which override this method should take care to also call the base class method in order to write common metadata properties.

Reimplemented from QgsAbstractMetadataBase.

Definition at line 247 of file qgslayermetadata.cpp.

The documentation for this class was generated from the following files:

/build/qgis-3.99.0+git20251210+2fe06baccd8+99sid/src/core/metadata/qgslayermetadata.h
/build/qgis-3.99.0+git20251210+2fe06baccd8+99sid/src/core/metadata/qgslayermetadata.cpp

Classes

Public Types

Public Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ ConstraintList

Constructor & Destructor Documentation

◆ QgsLayerMetadata()

Member Function Documentation

◆ addConstraint()

◆ clone()

◆ combine()

◆ constraints()

◆ contains()

◆ crs()

◆ encoding()

◆ extent() [1/2]

◆ extent() [2/2]

◆ fees()

◆ licenses()

◆ matches()

◆ operator==()

◆ readFromLayer()

◆ readMetadataXml()

◆ registerTranslations()

◆ rights()

◆ saveToLayer()

◆ setConstraints()

◆ setCrs()

◆ setEncoding()

◆ setExtent()

◆ setFees()

◆ setLicenses()

◆ setRights()

◆ writeMetadataXml()