Merge pull request #6501 from alexbruy/multi-ring

[processing][FEATURE] add multi-ring buffer algorithm
qgis · Mar 2, 2018 · ae9bd06 · ae9bd06
2 parents b61882f + df61548
commit ae9bd06
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diff --git a/python/plugins/processing/tests/testdata/expected/multiring_buffer.gml b/python/plugins/processing/tests/testdata/expected/multiring_buffer.gml
diff --git a/python/plugins/processing/tests/testdata/expected/multiring_buffer.xsd b/python/plugins/processing/tests/testdata/expected/multiring_buffer.xsd
@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<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">
+<xs:import namespace="http://www.opengis.net/gml" schemaLocation="http://schemas.opengis.net/gml/2.1.2/feature.xsd"/>
+<xs:element name="FeatureCollection" type="ogr:FeatureCollectionType" substitutionGroup="gml:_FeatureCollection"/>
+<xs:complexType name="FeatureCollectionType">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureCollectionType">
+      <xs:attribute name="lockId" type="xs:string" use="optional"/>
+      <xs:attribute name="scope" type="xs:string" use="optional"/>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+<xs:element name="multiring_buffer" type="ogr:multiring_buffer_Type" substitutionGroup="gml:_Feature"/>
+<xs:complexType name="multiring_buffer_Type">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureType">
+      <xs:sequence>
+        <xs:element name="geometryProperty" type="gml:PolygonPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
+        <xs:element name="id" nillable="true" minOccurs="0" maxOccurs="1">
+          <xs:simpleType>
+            <xs:restriction base="xs:integer">
+              <xs:totalDigits value="10"/>
+            </xs:restriction>
+          </xs:simpleType>
+        </xs:element>
+        <xs:element name="id2" nillable="true" minOccurs="0" maxOccurs="1">
+          <xs:simpleType>
+            <xs:restriction base="xs:integer">
+              <xs:totalDigits value="10"/>
+            </xs:restriction>
+          </xs:simpleType>
+        </xs:element>
+        <xs:element name="ringId" nillable="true" minOccurs="0" maxOccurs="1">
+          <xs:simpleType>
+            <xs:restriction base="xs:integer">
+              <xs:totalDigits value="10"/>
+            </xs:restriction>
+          </xs:simpleType>
+        </xs:element>
+        <xs:element name="distance" nillable="true" minOccurs="0" maxOccurs="1">
+          <xs:simpleType>
+            <xs:restriction base="xs:decimal">
+              <xs:totalDigits value="21"/>
+              <xs:fractionDigits value="6"/>
+            </xs:restriction>
+          </xs:simpleType>
+        </xs:element>
+      </xs:sequence>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+</xs:schema>
diff --git a/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml b/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml
@@ -4765,3 +4765,16 @@ tests:
       OUTPUT:
         name: expected/biggest_parts.gml
         type: vector
+
+  - algorithm: native:multiringconstantbuffer
+    name: Multi-ring buffer with points
+    params:
+      DISTANCE: 0.05
+      INPUT:
+        name: points.gml
+        type: vector
+      RINGS: 3
+    results:
+      OUTPUT:
+        name: expected/multiring_buffer.gml
+        type: vector
diff --git a/src/analysis/CMakeLists.txt b/src/analysis/CMakeLists.txt
@@ -47,6 +47,7 @@ SET(QGIS_ANALYSIS_SRCS
   processing/qgsalgorithmmergevector.cpp
   processing/qgsalgorithmminimumenclosingcircle.cpp
   processing/qgsalgorithmmultiparttosinglepart.cpp
+  processing/qgsalgorithmmultiringconstantbuffer.cpp
   processing/qgsalgorithmorderbyexpression.cpp
   processing/qgsalgorithmorientedminimumboundingbox.cpp
   processing/qgsalgorithmpackage.cpp

diff --git a/src/analysis/processing/qgsalgorithmmultiringconstantbuffer.cpp b/src/analysis/processing/qgsalgorithmmultiringconstantbuffer.cpp
@@ -0,0 +1,147 @@
+/***************************************************************************
+                         qgsalgorithmnultitingconstantbuffer.cpp
+                         --------------------------
+    begin                : February 2018
+    copyright            : (C) 2018 by Alexander Bruy
+    email                : alexander dot bruy at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsalgorithmmultiringconstantbuffer.h"
+
+///@cond PRIVATE
+
+QString QgsMultiRingConstantBufferAlgorithm::name() const
+{
+  return QStringLiteral( "multiringconstantbuffer" );
+}
+
+QString QgsMultiRingConstantBufferAlgorithm::displayName() const
+{
+  return QObject::tr( "Multi-ring buffer (constant distance)" );
+}
+
+QStringList QgsMultiRingConstantBufferAlgorithm::tags() const
+{
+  return QObject::tr( "buffer,grow,multiple,rings,distance,donut" ).split( ',' );
+}
+
+QString QgsMultiRingConstantBufferAlgorithm::group() const
+{
+  return QObject::tr( "Vector geometry" );
+}
+
+QString QgsMultiRingConstantBufferAlgorithm::groupId() const
+{
+  return QStringLiteral( "vectorgeometry" );
+}
+
+QString QgsMultiRingConstantBufferAlgorithm::outputName() const
+{
+  return QObject::tr( "Multi-ring buffer (constant distance)" );
+}
+
+QString QgsMultiRingConstantBufferAlgorithm::shortHelpString() const
+{
+  return QObject::tr( "This algorithm computes multi-ring ('donuts') buffer for all the features in an input layer, using a fixed or dynamic distance and rings number." );
+}
+
+QgsMultiRingConstantBufferAlgorithm *QgsMultiRingConstantBufferAlgorithm::createInstance() const
+{
+  return new QgsMultiRingConstantBufferAlgorithm();
+}
+
+void QgsMultiRingConstantBufferAlgorithm::initParameters( const QVariantMap & )
+{
+  std::unique_ptr< QgsProcessingParameterNumber> rings = qgis::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "RINGS" ),
+      QObject::tr( "Number of rings" ), QgsProcessingParameterNumber::Integer,
+      1, false, 0 );
+  rings->setIsDynamic( true );
+  rings->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "RINGS" ), QObject::tr( "Number of rings" ), QgsPropertyDefinition::IntegerPositive ) );
+  rings->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
+  addParameter( rings.release() );
+
+  std::unique_ptr< QgsProcessingParameterNumber> distance = qgis::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "DISTANCE" ),
+      QObject::tr( "Distance between rings" ), QgsProcessingParameterNumber::Double,
+      1, false, 0 );
+  distance->setIsDynamic( true );
+  distance->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "DISTANCE" ), QObject::tr( "Distance between rings" ), QgsPropertyDefinition::DoublePositive ) );
+  distance->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
+  addParameter( distance.release() );
+}
+
+bool QgsMultiRingConstantBufferAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  mRingsNumber = parameterAsInt( parameters, QStringLiteral( "RINGS" ), context );
+  mDynamicRingsNumber = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "RINGS" ) );
+  if ( mDynamicRingsNumber )
+    mRingsNumberProperty = parameters.value( QStringLiteral( "RINGS" ) ).value< QgsProperty >();
+
+  mDistance = parameterAsDouble( parameters, QStringLiteral( "DISTANCE" ), context );
+  mDynamicDistance = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "DISTANCE" ) );
+  if ( mDynamicDistance )
+    mDistanceProperty = parameters.value( QStringLiteral( "DISTANCE" ) ).value< QgsProperty >();
+
+  return true;
+}
+
+QgsFields QgsMultiRingConstantBufferAlgorithm::outputFields( const QgsFields &inputFields ) const
+{
+  QgsFields fields = inputFields;
+  fields.append( QgsField( QStringLiteral( "ringId" ), QVariant::Int, QString(), 10, 0 ) );
+  fields.append( QgsField( QStringLiteral( "distance" ), QVariant::Double, QString(), 20, 6 ) );
+  return fields;
+}
+
+QgsFeatureList QgsMultiRingConstantBufferAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
+{
+  double currentDistance = 0;
+  QgsGeometry outputGeometry, previousGeometry;
+
+  int rings = mRingsNumber;
+  if ( mDynamicRingsNumber )
+    rings = mRingsNumberProperty.valueAsInt( context.expressionContext(), rings );
+
+  double distance = mDistance;
+  if ( mDynamicDistance )
+    distance = mDistanceProperty.valueAsDouble( context.expressionContext(), distance );
+
+  QgsFeatureList outputs;
+
+  for ( int i = 1; i <= mRingsNumber; ++i )
+  {
+    QgsFeature out;
+    currentDistance = i * distance;
+    outputGeometry = feature.geometry().buffer( currentDistance, 40 );
+    if ( !outputGeometry )
+    {
+      feedback->reportError( QObject::tr( "Error calculating buffer for feature %1" ).arg( feature.id() ) );
+      continue;
+    }
+
+    if ( i == 1 )
+    {
+      out.setGeometry( outputGeometry );
+    }
+    else
+    {
+      out.setGeometry( outputGeometry.symDifference( previousGeometry ) );
+    }
+    previousGeometry = outputGeometry;
+    QgsAttributes attrs = feature.attributes();
+    attrs << i << currentDistance;
+    out.setAttributes( attrs );
+    outputs.append( out );
+  }
+  return outputs;
+}
+
+///@endcond
diff --git a/src/analysis/processing/qgsalgorithmmultiringconstantbuffer.h b/src/analysis/processing/qgsalgorithmmultiringconstantbuffer.h
@@ -0,0 +1,69 @@
+/***************************************************************************
+                         qgsalgorithmmultiringconstantbuffer.h
+                         -------------------------
+    begin                : February 2018
+    copyright            : (C) 2018 by Alexander Bruy
+    email                : alexander dot bruy at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSALGORITHMMULTIRINGCONSTANTBUFFER_H
+#define QGSALGORITHMMULTIRINGCONSTANTBUFFER_H
+
+#define SIP_NO_FILE
+
+#include "qgis.h"
+#include "qgsprocessingalgorithm.h"
+
+///@cond PRIVATE
+
+/**
+ * Native multiring buffer algorithm.
+ */
+class QgsMultiRingConstantBufferAlgorithm : public QgsProcessingFeatureBasedAlgorithm
+{
+
+  public:
+
+    QgsMultiRingConstantBufferAlgorithm() = default;
+    QString name() const override;
+    QString displayName() const override;
+    QStringList tags() const override;
+    QString group() const override;
+    QString groupId() const override;
+    QString shortHelpString() const override;
+    QgsMultiRingConstantBufferAlgorithm *createInstance() const override SIP_FACTORY;
+    void initParameters( const QVariantMap &configuration = QVariantMap() ) override;
+
+  protected:
+
+    QString outputName() const override;
+    QgsFields outputFields( const QgsFields &inputFields ) const override;
+    QgsProcessing::SourceType outputLayerType() const override { return QgsProcessing::TypeVectorPolygon; }
+    QgsWkbTypes::Type outputWkbType( QgsWkbTypes::Type inputWkbType ) const override { Q_UNUSED( inputWkbType ); return QgsWkbTypes::Polygon; }
+    bool prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
+    QgsFeatureList processFeature( const QgsFeature &feature,  QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
+
+  private:
+    int mRingsNumber = 0;
+    bool mDynamicRingsNumber = false;
+    QgsProperty mRingsNumberProperty;
+
+    double mDistance = 0.0;
+    bool mDynamicDistance = false;
+    QgsProperty mDistanceProperty;
+};
+
+///@endcond PRIVATE
+
+#endif // QGSALGORITHMMULTIRINGCONSTANTBUFFER_H
+
+
diff --git a/src/analysis/processing/qgsnativealgorithms.cpp b/src/analysis/processing/qgsnativealgorithms.cpp
@@ -44,6 +44,7 @@
 #include "qgsalgorithmmergevector.h"
 #include "qgsalgorithmminimumenclosingcircle.h"
 #include "qgsalgorithmmultiparttosinglepart.h"
+#include "qgsalgorithmmultiringconstantbuffer.h"
 #include "qgsalgorithmorderbyexpression.h"
 #include "qgsalgorithmorientedminimumboundingbox.h"
 #include "qgsalgorithmpackage.h"
@@ -134,6 +135,7 @@ void QgsNativeAlgorithms::loadAlgorithms()
   addAlgorithm( new QgsMergeVectorAlgorithm() );
   addAlgorithm( new QgsMinimumEnclosingCircleAlgorithm() );
   addAlgorithm( new QgsMultipartToSinglepartAlgorithm() );
+  addAlgorithm( new QgsMultiRingConstantBufferAlgorithm() );
   addAlgorithm( new QgsOrderByExpressionAlgorithm() );
   addAlgorithm( new QgsOrientedMinimumBoundingBoxAlgorithm() );
   addAlgorithm( new QgsPackageAlgorithm() );