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[FEATURE][processing] Add "raster pixels to points" algorithm
Refactor the existing "raster pixels to polygons" algorithm and create a new "pixels to points" algorithm, which creates a point feature at the center of every pixel. nodata pixels are skipped.
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8 files changed

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lines changed

‎python/plugins/processing/tests/testdata/expected/pixels_to_points.gml

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‎python/plugins/processing/tests/testdata/expected/pixels_to_points.xsd

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<?xml version="1.0" encoding="UTF-8"?>
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<xs:schema targetNamespace="http://ogr.maptools.org/" xmlns:ogr="http://ogr.maptools.org/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:gml="http://www.opengis.net/gml" elementFormDefault="qualified" version="1.0">
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<xs:import namespace="http://www.opengis.net/gml" schemaLocation="http://schemas.opengis.net/gml/2.1.2/feature.xsd"/>
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<xs:element name="FeatureCollection" type="ogr:FeatureCollectionType" substitutionGroup="gml:_FeatureCollection"/>
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<xs:complexType name="FeatureCollectionType">
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<xs:complexContent>
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<xs:extension base="gml:AbstractFeatureCollectionType">
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<xs:attribute name="lockId" type="xs:string" use="optional"/>
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<xs:attribute name="scope" type="xs:string" use="optional"/>
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</xs:extension>
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</xs:complexContent>
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</xs:complexType>
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<xs:element name="pixels_to_points" type="ogr:pixels_to_points_Type" substitutionGroup="gml:_Feature"/>
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<xs:complexType name="pixels_to_points_Type">
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<xs:complexContent>
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<xs:extension base="gml:AbstractFeatureType">
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<xs:sequence>
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<xs:element name="geometryProperty" type="gml:PointPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
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<xs:element name="VALUE" nillable="true" minOccurs="0" maxOccurs="1">
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<xs:simpleType>
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<xs:restriction base="xs:decimal">
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<xs:totalDigits value="21"/>
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<xs:fractionDigits value="8"/>
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</xs:restriction>
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</xs:simpleType>
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</xs:element>
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</xs:sequence>
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</xs:extension>
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</xs:complexContent>
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</xs:complexType>
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</xs:schema>

‎python/plugins/processing/tests/testdata/expected/pointsvoronoi1diagram.gfs

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<GMLFeatureClassList>
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<GMLFeatureClass>
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<Name>pointsvoronoi1diagram</Name>
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<ElementPath>pointsvoronoi1diagram</ElementPath>
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<!--POLYGON-->
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<GeometryType>3</GeometryType>
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<SRSName>EPSG:4326</SRSName>
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<DatasetSpecificInfo>
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<FeatureCount>6</FeatureCount>
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<ExtentXMin>-0.60000</ExtentXMin>
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<ExtentXMax>0.20000</ExtentXMax>
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<ExtentYMin>51.40000</ExtentYMin>
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<ExtentYMax>51.60000</ExtentYMax>
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</DatasetSpecificInfo>
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<PropertyDefn>
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<Name>id</Name>
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<ElementPath>id</ElementPath>
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<Type>Integer</Type>
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</PropertyDefn>
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</GMLFeatureClass>
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</GMLFeatureClassList>

‎python/plugins/processing/tests/testdata/pointsvoronoi1.gfs

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<GMLFeatureClassList>
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<GMLFeatureClass>
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<Name>pointsvoronoi1</Name>
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<ElementPath>pointsvoronoi1</ElementPath>
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<!--POINT-->
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<GeometryType>1</GeometryType>
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<SRSName>EPSG:4326</SRSName>
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<DatasetSpecificInfo>
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<FeatureCount>6</FeatureCount>
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<ExtentXMin>-0.60000</ExtentXMin>
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<ExtentXMax>0.20000</ExtentXMax>
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<ExtentYMin>51.40000</ExtentYMin>
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<ExtentYMax>51.60000</ExtentYMax>
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</DatasetSpecificInfo>
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<PropertyDefn>
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<Name>id</Name>
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<ElementPath>id</ElementPath>
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<Type>Integer</Type>
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</PropertyDefn>
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</GMLFeatureClass>
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</GMLFeatureClassList>

‎python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml

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name: expected/vectorize.gml
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type: vector
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- algorithm: native:pixelstopoints
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name: Pixels to points
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params:
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FIELD_NAME: VALUE
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INPUT_RASTER:
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name: raster.tif
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type: raster
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RASTER_BAND: 1
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results:
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OUTPUT:
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name: expected/pixels_to_points.gml
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type: vector
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- algorithm: native:kmeansclustering
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name: K means, points, 3 clusters
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params:

‎src/analysis/processing/qgsalgorithmvectorize.cpp

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///@cond PRIVATE
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24-
QString QgsVectorizeAlgorithm::name() const
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{
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return QStringLiteral( "pixelstopolygons" );
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}
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QString QgsVectorizeAlgorithm::displayName() const
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{
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return QObject::tr( "Raster pixels to polygons" );
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}
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QStringList QgsVectorizeAlgorithm::tags() const
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{
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return QObject::tr( "vectorize,polygonize,raster,convert,pixels" ).split( ',' );
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}
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QString QgsVectorizeAlgorithm::shortHelpString() const
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{
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return QObject::tr( "This algorithm converts a raster layer to a vector layer, by creating polygon features for each individual pixel in the raster layer." );
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}
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QgsVectorizeAlgorithm *QgsVectorizeAlgorithm::createInstance() const
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{
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return new QgsVectorizeAlgorithm();
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}
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QString QgsVectorizeAlgorithm::group() const
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QString QgsVectorizeAlgorithmBase::group() const
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{
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return QObject::tr( "Vector creation" );
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}
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QString QgsVectorizeAlgorithm::groupId() const
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QString QgsVectorizeAlgorithmBase::groupId() const
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{
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return QStringLiteral( "vectorcreation" );
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}
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void QgsVectorizeAlgorithm::initAlgorithm( const QVariantMap & )
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void QgsVectorizeAlgorithmBase::initAlgorithm( const QVariantMap & )
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{
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addParameter( new QgsProcessingParameterRasterLayer( QStringLiteral( "INPUT_RASTER" ),
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QObject::tr( "Raster layer" ) ) );
@@ -65,10 +40,10 @@ void QgsVectorizeAlgorithm::initAlgorithm( const QVariantMap & )
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addParameter( new QgsProcessingParameterString( QStringLiteral( "FIELD_NAME" ),
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QObject::tr( "Field name" ), QStringLiteral( "VALUE" ) ) );
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addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Vectorized layer" ), QgsProcessing::TypeVectorPolygon ) );
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addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), outputName(), outputType() ) );
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}
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bool QgsVectorizeAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
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bool QgsVectorizeAlgorithmBase::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
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{
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QgsRasterLayer *layer = parameterAsRasterLayer( parameters, QStringLiteral( "INPUT_RASTER" ), context );
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return true;
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}
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QVariantMap QgsVectorizeAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
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QVariantMap QgsVectorizeAlgorithmBase::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
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{
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const QString fieldName = parameterAsString( parameters, QStringLiteral( "FIELD_NAME" ), context );
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QgsFields fields;
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fields.append( QgsField( fieldName, QVariant::Double, QString(), 20, 8 ) );
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QString dest;
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std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, fields, QgsWkbTypes::Polygon, mCrs ) );
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std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, fields, sinkType(), mCrs ) );
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if ( !sink )
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throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
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int nbBlocksHeight = static_cast< int >( std::ceil( 1.0 * mNbCellsYProvider / maxHeight ) );
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int nbBlocks = nbBlocksWidth * nbBlocksHeight;
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double hCellSizeX = mRasterUnitsPerPixelX / 2.0;
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double hCellSizeY = mRasterUnitsPerPixelY / 2.0;
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int iterLeft = 0;
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int iterTop = 0;
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int iterCols = 0;
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{
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if ( !rasterBlock->isNoData( row, column ) )
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{
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QgsGeometry pixelRectGeometry = QgsGeometry::fromRect( QgsRectangle( currentX - hCellSizeX, currentY - hCellSizeY, currentX + hCellSizeX, currentY + hCellSizeY ) );
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QgsGeometry pixelRectGeometry = createGeometryForPixel( currentX, currentY, mRasterUnitsPerPixelX, mRasterUnitsPerPixelY );
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double value = rasterBlock->value( row, column );
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QgsFeature f;
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return outputs;
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}
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//
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// QgsRasterPixelsToPolygonsAlgorithm
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//
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QString QgsRasterPixelsToPolygonsAlgorithm::name() const
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{
141+
return QStringLiteral( "pixelstopolygons" );
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}
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QString QgsRasterPixelsToPolygonsAlgorithm::displayName() const
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{
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return QObject::tr( "Raster pixels to polygons" );
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}
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QStringList QgsRasterPixelsToPolygonsAlgorithm::tags() const
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{
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return QObject::tr( "vectorize,polygonize,raster,convert,pixels" ).split( ',' );
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}
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QString QgsRasterPixelsToPolygonsAlgorithm::shortHelpString() const
155+
{
156+
return QObject::tr( "This algorithm converts a raster layer to a vector layer, by creating polygon features "
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"for each individual pixel's extent in the raster layer.\n\n"
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"Any nodata pixels are skipped in the output." );
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}
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QString QgsRasterPixelsToPolygonsAlgorithm::shortDescription() const
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{
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return QObject::tr( "Creates a vector layer of polygons corresponding to each pixel in a raster layer." );
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}
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QgsRasterPixelsToPolygonsAlgorithm *QgsRasterPixelsToPolygonsAlgorithm::createInstance() const
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{
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return new QgsRasterPixelsToPolygonsAlgorithm();
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}
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QString QgsRasterPixelsToPolygonsAlgorithm::outputName() const
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{
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return QObject::tr( "Vector polygons" );
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}
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QgsProcessing::SourceType QgsRasterPixelsToPolygonsAlgorithm::outputType() const
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{
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return QgsProcessing::TypeVectorPolygon;
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}
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QgsWkbTypes::Type QgsRasterPixelsToPolygonsAlgorithm::sinkType() const
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{
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return QgsWkbTypes::Polygon;
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}
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QgsGeometry QgsRasterPixelsToPolygonsAlgorithm::createGeometryForPixel( double centerX, double centerY, double pixelWidthX, double pixelWidthY ) const
187+
{
188+
const double hCellSizeX = pixelWidthX / 2.0;
189+
const double hCellSizeY = pixelWidthY / 2.0;
190+
return QgsGeometry::fromRect( QgsRectangle( centerX - hCellSizeX, centerY - hCellSizeY, centerX + hCellSizeX, centerY + hCellSizeY ) );
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}
192+
193+
194+
//
195+
// QgsRasterPixelsToPointsAlgorithm
196+
//
197+
198+
QString QgsRasterPixelsToPointsAlgorithm::name() const
199+
{
200+
return QStringLiteral( "pixelstopoints" );
201+
}
202+
203+
QString QgsRasterPixelsToPointsAlgorithm::displayName() const
204+
{
205+
return QObject::tr( "Raster pixels to points" );
206+
}
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208+
QStringList QgsRasterPixelsToPointsAlgorithm::tags() const
209+
{
210+
return QObject::tr( "vectorize,polygonize,raster,convert,pixels,centers" ).split( ',' );
211+
}
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213+
QString QgsRasterPixelsToPointsAlgorithm::shortHelpString() const
214+
{
215+
return QObject::tr( "This algorithm converts a raster layer to a vector layer, by creating point features "
216+
"for each individual pixel's center in the raster layer.\n\n"
217+
"Any nodata pixels are skipped in the output." );
218+
}
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220+
QString QgsRasterPixelsToPointsAlgorithm::shortDescription() const
221+
{
222+
return QObject::tr( "Creates a vector layer of points corresponding to each pixel in a raster layer." );
223+
}
224+
225+
QgsRasterPixelsToPointsAlgorithm *QgsRasterPixelsToPointsAlgorithm::createInstance() const
226+
{
227+
return new QgsRasterPixelsToPointsAlgorithm();
228+
}
229+
230+
QString QgsRasterPixelsToPointsAlgorithm::outputName() const
231+
{
232+
return QObject::tr( "Vector points" );
233+
}
234+
235+
QgsProcessing::SourceType QgsRasterPixelsToPointsAlgorithm::outputType() const
236+
{
237+
return QgsProcessing::TypeVectorPoint;
238+
}
239+
240+
QgsWkbTypes::Type QgsRasterPixelsToPointsAlgorithm::sinkType() const
241+
{
242+
return QgsWkbTypes::Point;
243+
}
244+
245+
QgsGeometry QgsRasterPixelsToPointsAlgorithm::createGeometryForPixel( double centerX, double centerY, double, double ) const
246+
{
247+
return QgsGeometry( new QgsPoint( centerX, centerY ) );
248+
}
249+
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///@endcond
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