26QString QgsJoinByNearestAlgorithm::name()
const
28 return QStringLiteral(
"joinbynearest" );
31QString QgsJoinByNearestAlgorithm::displayName()
const
33 return QObject::tr(
"Join attributes by nearest" );
36QStringList QgsJoinByNearestAlgorithm::tags()
const
38 return QObject::tr(
"join,connect,attributes,values,fields,tables,proximity,closest,neighbour,neighbor,n-nearest,distance" ).split(
',' );
41QString QgsJoinByNearestAlgorithm::group()
const
43 return QObject::tr(
"Vector general" );
46QString QgsJoinByNearestAlgorithm::groupId()
const
48 return QStringLiteral(
"vectorgeneral" );
51void QgsJoinByNearestAlgorithm::initAlgorithm(
const QVariantMap & )
54 QObject::tr(
"Input layer" ) ) );
56 QObject::tr(
"Input layer 2" ) ) );
59 QObject::tr(
"Layer 2 fields to copy (leave empty to copy all fields)" ),
64 QObject::tr(
"Discard records which could not be joined" ),
68 QObject::tr(
"Joined field prefix" ), QVariant(),
false,
true ) );
74 QObject::tr(
"Maximum distance" ), QVariant(), QStringLiteral(
"INPUT" ),
true, 0 ) );
78 std::unique_ptr< QgsProcessingParameterFeatureSink > nonMatchingSink = std::make_unique< QgsProcessingParameterFeatureSink >(
82 addParameter( nonMatchingSink.release() );
84 addOutput(
new QgsProcessingOutputNumber( QStringLiteral(
"JOINED_COUNT" ), QObject::tr(
"Number of joined features from input table" ) ) );
85 addOutput(
new QgsProcessingOutputNumber( QStringLiteral(
"UNJOINABLE_COUNT" ), QObject::tr(
"Number of unjoinable features from input table" ) ) );
88QString QgsJoinByNearestAlgorithm::shortHelpString()
const
90 return QObject::tr(
"This algorithm takes an input vector layer and creates a new vector layer that is an extended version of the "
91 "input one, with additional attributes in its attribute table.\n\n"
92 "The additional attributes and their values are taken from a second vector layer, where features are joined "
93 "by finding the closest features from each layer. By default only the single nearest feature is joined,"
94 "but optionally the join can use the n-nearest neighboring features instead. If multiple features are found "
95 "with identical distances these will all be returned (even if the total number of features exceeds the specified "
96 "maximum feature count).\n\n"
97 "If a maximum distance is specified, then only features which are closer than this distance "
98 "will be matched.\n\n"
99 "The output features will contain the selected attributes from the nearest feature, "
100 "along with new attributes for the distance to the near feature, the index of the feature, "
101 "and the coordinates of the closest point on the input feature (feature_x, feature_y) "
102 "to the matched nearest feature, and the coordinates of the closet point on the matched feature "
103 "(nearest_x, nearest_y).\n\n"
104 "This algorithm uses purely Cartesian calculations for distance, and does not consider "
105 "geodetic or ellipsoid properties when determining feature proximity." );
108QString QgsJoinByNearestAlgorithm::shortDescription()
const
110 return QObject::tr(
"Joins a layer to another layer, using the closest features (nearest neighbors)." );
118QgsJoinByNearestAlgorithm *QgsJoinByNearestAlgorithm::createInstance()
const
120 return new QgsJoinByNearestAlgorithm();
125 const int neighbors = parameterAsInt( parameters, QStringLiteral(
"NEIGHBORS" ), context );
126 const bool discardNonMatching = parameterAsBoolean( parameters, QStringLiteral(
"DISCARD_NONMATCHING" ), context );
127 const double maxDistance = parameters.value( QStringLiteral(
"MAX_DISTANCE" ) ).isValid() ? parameterAsDouble( parameters, QStringLiteral(
"MAX_DISTANCE" ), context ) : std::numeric_limits< double >::quiet_NaN();
128 std::unique_ptr< QgsProcessingFeatureSource > input( parameterAsSource( parameters, QStringLiteral(
"INPUT" ), context ) );
132 std::unique_ptr< QgsProcessingFeatureSource > input2( parameterAsSource( parameters, QStringLiteral(
"INPUT_2" ), context ) );
136 const bool sameSourceAndTarget = parameters.value( QStringLiteral(
"INPUT" ) ) == parameters.value( QStringLiteral(
"INPUT_2" ) );
138 const QString prefix = parameterAsString( parameters, QStringLiteral(
"PREFIX" ), context );
139 const QStringList fieldsToCopy = parameterAsStrings( parameters, QStringLiteral(
"FIELDS_TO_COPY" ), context );
143 if ( fieldsToCopy.empty() )
145 outFields2 = input2->fields();
146 fields2Indices.reserve( outFields2.
count() );
147 for (
int i = 0; i < outFields2.
count(); ++i )
154 fields2Indices.reserve( fieldsToCopy.count() );
155 for (
const QString &field : fieldsToCopy )
157 const int index = input2->fields().
lookupField( field );
160 fields2Indices << index;
161 outFields2.
append( input2->fields().at( index ) );
166 if ( !prefix.isEmpty() )
168 for (
int i = 0; i < outFields2.
count(); ++i )
170 outFields2.
rename( i, prefix + outFields2[ i ].name() );
179 resultFields.
append(
QgsField( QStringLiteral(
"n" ), QMetaType::Type::Int ) );
180 resultFields.
append(
QgsField( QStringLiteral(
"distance" ), QMetaType::Type::Double ) );
181 resultFields.
append(
QgsField( QStringLiteral(
"feature_x" ), QMetaType::Type::Double ) );
182 resultFields.
append(
QgsField( QStringLiteral(
"feature_y" ), QMetaType::Type::Double ) );
183 resultFields.
append(
QgsField( QStringLiteral(
"nearest_x" ), QMetaType::Type::Double ) );
184 resultFields.
append(
QgsField( QStringLiteral(
"nearest_y" ), QMetaType::Type::Double ) );
188 std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral(
"OUTPUT" ), context, dest, outFields,
190 if ( parameters.value( QStringLiteral(
"OUTPUT" ) ).isValid() && !sink )
193 QString destNonMatching1;
194 std::unique_ptr< QgsFeatureSink > sinkNonMatching1( parameterAsSink( parameters, QStringLiteral(
"NON_MATCHING" ), context, destNonMatching1, input->fields(),
196 if ( parameters.value( QStringLiteral(
"NON_MATCHING" ) ).isValid() && !sinkNonMatching1 )
201 QHash< QgsFeatureId, QgsAttributes > input2AttributeCache;
202 double step = input2->featureCount() > 0 ? 50.0 / input2->featureCount() : 1;
218 for (
int j = 0; j < attributeCount; ++j )
220 if ( ! fields2Indices.contains( j ) )
224 input2AttributeCache.insert( f.
id(), attributes );
233 nullMatch.reserve( fields2Indices.size() + 6 );
234 for (
int i = 0; i < fields2Indices.count() + 6; ++i )
235 nullMatch << QVariant();
237 long long joinedCount = 0;
238 long long unjoinedCount = 0;
241 step = input->featureCount() > 0 ? 50.0 / input->featureCount() : 1;
254 if ( !f.hasGeometry() )
257 if ( sinkNonMatching1 )
260 throw QgsProcessingException( writeFeatureError( sinkNonMatching1.get(), parameters, QStringLiteral(
"NON_MATCHING" ) ) );
262 if ( sink && !discardNonMatching )
265 attr.append( nullMatch );
266 f.setAttributes( attr );
277 const double searchDistance = std::isnan( maxDistance ) ? 0 : std::max( std::numeric_limits<double>::min(), maxDistance );
278 const QList< QgsFeatureId > nearest = index.nearestNeighbor( f.geometry(), neighbors + ( sameSourceAndTarget ? 1 : 0 ), searchDistance );
280 if ( nearest.count() > neighbors + ( sameSourceAndTarget ? 1 : 0 ) )
282 feedback->
pushInfo( QObject::tr(
"Multiple matching features found at same distance from search feature, found %n feature(s) instead of %1",
nullptr, nearest.count() - ( sameSourceAndTarget ? 1 : 0 ) ).arg( neighbors ) );
289 if ( sameSourceAndTarget &&
id == f.id() )
295 attr.append( input2AttributeCache.value(
id ) );
299 if (
const QgsLineString *line = qgsgeometry_cast< const QgsLineString *>( closestLine.
constGet() ) )
301 attr.append( line->length() );
302 attr.append( line->startPoint().x() );
303 attr.append( line->startPoint().y() );
304 attr.append( line->endPoint().x() );
305 attr.append( line->endPoint().y() );
309 attr.append( QVariant() );
310 attr.append( QVariant() );
311 attr.append( QVariant() );
312 attr.append( QVariant() );
313 attr.append( QVariant() );
324 if ( sinkNonMatching1 )
327 throw QgsProcessingException( writeFeatureError( sinkNonMatching1.get(), parameters, QStringLiteral(
"NON_MATCHING" ) ) );
329 if ( !discardNonMatching && sink )
332 attr.append( nullMatch );
333 f.setAttributes( attr );
343 outputs.insert( QStringLiteral(
"JOINED_COUNT" ), joinedCount );
344 outputs.insert( QStringLiteral(
"UNJOINABLE_COUNT" ), unjoinedCount );
346 outputs.insert( QStringLiteral(
"OUTPUT" ), dest );
347 if ( sinkNonMatching1 )
348 outputs.insert( QStringLiteral(
"NON_MATCHING" ), destNonMatching1 );
@ VectorAnyGeometry
Any vector layer with geometry.
@ RegeneratesPrimaryKey
Algorithm always drops any existing primary keys or FID values and regenerates them in outputs.
QFlags< ProcessingAlgorithmDocumentationFlag > ProcessingAlgorithmDocumentationFlags
Flags describing algorithm behavior for documentation purposes.
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.
This class wraps a request for features to a vector layer (or directly its vector data provider).
QgsFeatureRequest & setSubsetOfAttributes(const QgsAttributeList &attrs)
Set a subset of attributes that will be fetched.
@ FastInsert
Use faster inserts, at the cost of updating the passed features to reflect changes made at the provid...
@ RegeneratePrimaryKey
This flag indicates, that a primary key field cannot be guaranteed to be unique and the sink should i...
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.
int attributeCount() const
Returns the number of attributes attached to the feature.
bool hasGeometry() const
Returns true if the feature has an associated geometry.
Q_INVOKABLE QVariant attribute(const QString &name) const
Lookup attribute value by attribute name.
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.
Container of fields for a vector layer.
bool append(const QgsField &field, Qgis::FieldOrigin origin=Qgis::FieldOrigin::Provider, int originIndex=-1)
Appends a field.
Q_INVOKABLE int lookupField(const QString &fieldName) const
Looks up field's index from the field name.
bool rename(int fieldIdx, const QString &name)
Renames a name of field.
A geometry is the spatial representation of a feature.
const QgsAbstractGeometry * constGet() const
Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.
QgsGeometry shortestLine(const QgsGeometry &other) const
Returns the shortest line joining this geometry to another geometry.
Line string geometry type, with support for z-dimension and m-values.
Contains information about the context in which a processing algorithm is executed.
QgsCoordinateTransformContext transformContext() const
Returns the coordinate transform context.
Custom exception class for processing related exceptions.
Base class for providing feedback from a processing algorithm.
virtual void pushInfo(const QString &info)
Pushes a general informational message from the algorithm.
A numeric output for processing algorithms.
A boolean parameter for processing algorithms.
A double numeric parameter for distance values.
A feature sink output for processing algorithms.
An input feature source (such as vector layers) parameter for processing algorithms.
A vector layer or feature source field parameter for processing algorithms.
A numeric parameter for processing algorithms.
A string parameter for processing algorithms.
static QgsFields combineFields(const QgsFields &fieldsA, const QgsFields &fieldsB, const QString &fieldsBPrefix=QString())
Combines two field lists, avoiding duplicate field names (in a case-insensitive manner).
A spatial index for QgsFeature objects.
@ FlagStoreFeatureGeometries
Indicates that the spatial index should also store feature geometries. This requires more memory,...
qint64 QgsFeatureId
64 bit feature ids negative numbers are used for uncommitted/newly added features
QList< int > QgsAttributeList