24QString QgsAggregateAlgorithm::name()
const
26 return QStringLiteral(
"aggregate" );
29QString QgsAggregateAlgorithm::displayName()
const
31 return QObject::tr(
"Aggregate" );
34QString QgsAggregateAlgorithm::shortHelpString()
const
36 return QObject::tr(
"This algorithm take a vector or table layer and aggregate features based on a group by expression. Features for which group by expression return the same value are grouped together.\n\n"
37 "It is possible to group all source features together using constant value in group by parameter, example: NULL.\n\n"
38 "It is also possible to group features using multiple fields using Array function, example: Array(\"Field1\", \"Field2\").\n\n"
39 "Geometries (if present) are combined into one multipart geometry for each group.\n\n"
40 "Output attributes are computed depending on each given aggregate definition." );
43QStringList QgsAggregateAlgorithm::tags()
const
45 return QObject::tr(
"attributes,sum,mean,collect,dissolve,statistics" ).split(
',' );
48QString QgsAggregateAlgorithm::group()
const
50 return QObject::tr(
"Vector geometry" );
53QString QgsAggregateAlgorithm::groupId()
const
55 return QStringLiteral(
"vectorgeometry" );
58QgsAggregateAlgorithm *QgsAggregateAlgorithm::createInstance()
const
60 return new QgsAggregateAlgorithm();
63void QgsAggregateAlgorithm::initAlgorithm(
const QVariantMap & )
66 addParameter(
new QgsProcessingParameterExpression( QStringLiteral(
"GROUP_BY" ), QObject::tr(
"Group by expression (NULL to group all features)" ), QStringLiteral(
"NULL" ), QStringLiteral(
"INPUT" ) ) );
73 mSource.reset( parameterAsSource( parameters, QStringLiteral(
"INPUT" ), context ) );
77 mGroupBy = parameterAsExpression( parameters, QStringLiteral(
"GROUP_BY" ), context );
82 mGroupByExpression = createExpression( mGroupBy, context );
83 mGeometryExpression = createExpression( QStringLiteral(
"collect($geometry, %1)" ).arg( mGroupBy ), context );
85 const QVariantList aggregates = parameters.value( QStringLiteral(
"AGGREGATES" ) ).toList();
86 int currentAttributeIndex = 0;
87 for (
const QVariant &aggregate : aggregates )
89 const QVariantMap aggregateDef = aggregate.toMap();
91 const QString name = aggregateDef.value( QStringLiteral(
"name" ) ).toString();
95 const QMetaType::Type type =
static_cast<QMetaType::Type
>( aggregateDef.value( QStringLiteral(
"type" ) ).toInt() );
96 const QString
typeName = aggregateDef.value( QStringLiteral(
"type_name" ) ).toString();
97 const QMetaType::Type subType =
static_cast<QMetaType::Type
>( aggregateDef.value( QStringLiteral(
"sub_type" ) ).toInt() );
99 const int length = aggregateDef.value( QStringLiteral(
"length" ), 0 ).toInt();
100 const int precision = aggregateDef.value( QStringLiteral(
"precision" ), 0 ).toInt();
105 const QString aggregateType = aggregateDef.value( QStringLiteral(
"aggregate" ) ).toString();
106 const QString source = aggregateDef.value( QStringLiteral(
"input" ) ).toString();
107 const QString delimiter = aggregateDef.value( QStringLiteral(
"delimiter" ) ).toString();
110 if ( aggregateType == QLatin1String(
"first_value" ) )
114 else if ( aggregateType == QLatin1String(
"last_value" ) )
117 mAttributesRequireLastFeature << currentAttributeIndex;
119 else if ( aggregateType == QLatin1String(
"concatenate" ) || aggregateType == QLatin1String(
"concatenate_unique" ) )
121 expression = QStringLiteral(
"%1(%2, %3, %4, %5)" ).arg( aggregateType, source, mGroupBy, QStringLiteral(
"TRUE" ),
QgsExpression::quotedString( delimiter ) );
125 expression = QStringLiteral(
"%1(%2, %3)" ).arg( aggregateType, source, mGroupBy );
127 mExpressions.append( createExpression( expression, context ) );
128 currentAttributeIndex++;
136 QgsExpressionContext expressionContext = createExpressionContext( parameters, context, mSource.get() );
137 mGroupByExpression.prepare( &expressionContext );
140 const long long count = mSource->featureCount();
141 double progressStep = count > 0 ? 50.0 / count : 1;
142 long long current = 0;
144 QHash<QVariantList, Group> groups;
145 QVector<QVariantList> keys;
148 std::vector<std::unique_ptr<QgsFeatureSink>> groupSinks;
154 const QVariant groupByValue = mGroupByExpression.evaluate( &expressionContext );
155 if ( mGroupByExpression.hasEvalError() )
157 throw QgsProcessingException( QObject::tr(
"Evaluation error in group by expression \"%1\": %2" ).arg( mGroupByExpression.expression(), mGroupByExpression.evalErrorString() ) );
161 const QVariantList key = groupByValue.userType() == QMetaType::Type::QVariantList ? groupByValue.toList() : ( QVariantList() << groupByValue );
163 const auto groupIt = groups.find( key );
164 if ( groupIt == groups.end() )
166 QString
id = QStringLiteral(
"memory:" );
175 group.sink = sink.get();
177 groupSinks.emplace_back( std::move( sink ) );
179 group.firstFeature = feature;
180 group.lastFeature = feature;
188 groupIt->lastFeature = feature;
201 std::unique_ptr<QgsFeatureSink> sink( parameterAsSink( parameters, QStringLiteral(
"OUTPUT" ), context, destId, mFields,
QgsWkbTypes::multiType( mSource->wkbType() ), mSource->sourceCrs() ) );
207 progressStep = 50.0 / keys.size();
210 for (
const QVariantList &key : keys )
212 const Group &group = groups[key];
219 if ( mGeometryExpression.hasEvalError() )
221 throw QgsProcessingException( QObject::tr(
"Evaluation error in geometry expression \"%1\": %2" ).arg( mGeometryExpression.expression(), mGeometryExpression.evalErrorString() ) );
229 QStringList keyString;
230 for (
const QVariant &v : key )
231 keyString << v.toString();
233 throw QgsProcessingException( QObject::tr(
"Impossible to combine geometries for %1 = %2" ).arg( mGroupBy, keyString.join(
',' ) ) );
238 attributes.reserve( mExpressions.size() );
239 int currentAttributeIndex = 0;
240 for (
auto it = mExpressions.begin(); it != mExpressions.end(); ++it )
242 exprContext.
setFeature( mAttributesRequireLastFeature.contains( currentAttributeIndex ) ? group.lastFeature : group.firstFeature );
245 const QVariant value = it->evaluate( &exprContext );
246 if ( it->hasEvalError() )
248 throw QgsProcessingException( QObject::tr(
"Evaluation error in expression \"%1\": %2" ).arg( it->expression(), it->evalErrorString() ) );
250 attributes.append( value );
254 attributes.append( QVariant() );
256 currentAttributeIndex++;
267 feedback->
setProgress( 50 + current * progressStep );
275 results.insert( QStringLiteral(
"OUTPUT" ), destId );
279bool QgsAggregateAlgorithm::supportInPlaceEdit(
const QgsMapLayer *layer )
const
288 expr.setGeomCalculator( &mDa );
290 expr.setAreaUnits( context.
areaUnit() );
291 if ( expr.hasParserError() )
294 QObject::tr(
"Parser error in expression \"%1\": %2" ).arg( expressionString, expr.parserErrorString() )
@ Vector
Tables (i.e. vector layers with or without geometry). When used for a sink this indicates the sink ha...
static QgsExpressionContextScope * layerScope(const QgsMapLayer *layer)
Creates a new scope which contains variables and functions relating to a QgsMapLayer.
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
void appendScope(QgsExpressionContextScope *scope)
Appends a scope to the end of the context.
void setFeature(const QgsFeature &feature)
Convenience function for setting a feature for the context.
Class for parsing and evaluation of expressions (formerly called "search strings").
static QString quotedString(QString text)
Returns a quoted version of a string (in single quotes)
Wrapper for iterator of features from vector data provider or vector layer.
bool nextFeature(QgsFeature &f)
Fetch next feature and stores in f, returns true on success.
bool isValid() const
Will return if this iterator is valid.
This class wraps a request for features to a vector layer (or directly its vector data provider).
@ FastInsert
Use faster inserts, at the cost of updating the passed features to reflect changes made at the provid...
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
void setAttributes(const QgsAttributes &attrs)
Sets the feature's attributes.
void setGeometry(const QgsGeometry &geometry)
Set the feature's geometry.
bool isCanceled() const
Tells whether the operation has been canceled already.
void setProgress(double progress)
Sets the current progress for the feedback object.
Encapsulate a field in an attribute table or data source.
A geometry is the spatial representation of a feature.
QVector< QgsGeometry > asGeometryCollection() const
Returns contents of the geometry as a list of geometries.
bool isEmpty() const
Returns true if the geometry is empty (eg a linestring with no vertices, or a collection with no geom...
static QgsGeometry unaryUnion(const QVector< QgsGeometry > &geometries, const QgsGeometryParameters ¶meters=QgsGeometryParameters())
Compute the unary union on a list of geometries.
Base class for all map layer types.
Contains information about the context in which a processing algorithm is executed.
QgsCoordinateTransformContext transformContext() const
Returns the coordinate transform context.
Qgis::AreaUnit areaUnit() const
Returns the area unit to use for area calculations.
Qgis::DistanceUnit distanceUnit() const
Returns the distance unit to use for distance calculations.
QString ellipsoid() const
Returns the ellipsoid to use for distance and area calculations.
Custom exception class for processing related exceptions.
Base class for providing feedback from a processing algorithm.
A parameter for "aggregate" configurations, which consist of a definition of desired output fields,...
An expression parameter for processing algorithms.
A feature sink output for processing algorithms.
An input feature source (such as vector layers) parameter for processing algorithms.
static QgsFeatureSink * createFeatureSink(QString &destination, QgsProcessingContext &context, const QgsFields &fields, Qgis::WkbType geometryType, const QgsCoordinateReferenceSystem &crs, const QVariantMap &createOptions=QVariantMap(), const QStringList &datasourceOptions=QStringList(), const QStringList &layerOptions=QStringList(), QgsFeatureSink::SinkFlags sinkFlags=QgsFeatureSink::SinkFlags(), QgsRemappingSinkDefinition *remappingDefinition=nullptr)
Creates a feature sink ready for adding features.
static QgsMapLayer * mapLayerFromString(const QString &string, QgsProcessingContext &context, bool allowLoadingNewLayers=true, QgsProcessingUtils::LayerHint typeHint=QgsProcessingUtils::LayerHint::UnknownType, QgsProcessing::LayerOptionsFlags flags=QgsProcessing::LayerOptionsFlags())
Interprets a string as a map layer within the supplied context.
static Qgis::WkbType multiType(Qgis::WkbType type)
Returns the multi type for a WKB type.