Optimize extract nodes algorithm

qgis · Nov 13, 2017 · 7cb15c0 · 7cb15c0
1 parent 82644fb
commit 7cb15c0
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Showing 6 changed files with 196 additions and 124 deletions.
diff --git a/python/plugins/processing/algs/qgis/ExtractNodes.py b/python/plugins/processing/algs/qgis/ExtractNodes.py
diff --git a/python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py b/python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py
@@ -64,7 +64,6 @@
 from .ExportGeometryInfo import ExportGeometryInfo
 from .ExtendLines import ExtendLines
 from .ExtentFromLayer import ExtentFromLayer
-from .ExtractNodes import ExtractNodes
 from .ExtractSpecificNodes import ExtractSpecificNodes
 from .FieldPyculator import FieldsPyculator
 from .FieldsCalculator import FieldsCalculator
@@ -190,7 +189,6 @@ def getAlgs(self):
                 ExportGeometryInfo(),
                 ExtendLines(),
                 ExtentFromLayer(),
-                ExtractNodes(),
                 ExtractSpecificNodes(),
                 FieldsCalculator(),
                 FieldsMapper(),

diff --git a/src/analysis/CMakeLists.txt b/src/analysis/CMakeLists.txt
@@ -35,6 +35,7 @@ SET(QGIS_ANALYSIS_SRCS
   processing/qgsalgorithmextractbyexpression.cpp
   processing/qgsalgorithmextractbyextent.cpp
   processing/qgsalgorithmextractbylocation.cpp
+  processing/qgsalgorithmextractnodes.cpp
   processing/qgsalgorithmfiledownloader.cpp
   processing/qgsalgorithmfixgeometries.cpp
   processing/qgsalgorithmjoinbyattribute.cpp

diff --git a/src/analysis/processing/qgsalgorithmextractnodes.cpp b/src/analysis/processing/qgsalgorithmextractnodes.cpp
@@ -0,0 +1,137 @@
+/***************************************************************************
+                         qgsalgorithmextractnodes.cpp
+                         --------------------------
+    begin                : November 2017
+    copyright            : (C) 2017 by Mathieu Pellerin
+    email                : nirvn dot asia 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 "qgsalgorithmextractnodes.h"
+
+///@cond PRIVATE
+
+QString QgsExtractNodesAlgorithm::name() const
+{
+  return QStringLiteral( "extractnodes" );
+}
+
+QString QgsExtractNodesAlgorithm::displayName() const
+{
+  return QObject::tr( "Extract nodes" );
+}
+
+QStringList QgsExtractNodesAlgorithm::tags() const
+{
+  return QObject::tr( "points,vertex,vertices" ).split( ',' );
+}
+
+QString QgsExtractNodesAlgorithm::group() const
+{
+  return QObject::tr( "Vector geometry" );
+}
+
+QString QgsExtractNodesAlgorithm::shortHelpString() const
+{
+  return QObject::tr( "This algorithm takes a line or polygon layer and generates a point layer with points representing the nodes in the input lines or polygons. The attributes associated to each point are the same ones associated to the line or polygon that the point belongs to." ) +
+         QStringLiteral( "\n\n" )  +
+         QObject::tr( "Additional fields are added to the nodes indicating the node index (beginning at 0), distance along original geometry and bisector angle of node for original geometry." );
+}
+
+QgsExtractNodesAlgorithm *QgsExtractNodesAlgorithm::createInstance() const
+{
+  return new QgsExtractNodesAlgorithm();
+}
+
+void QgsExtractNodesAlgorithm::initAlgorithm( const QVariantMap & )
+{
+  addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INPUT" ), QObject::tr( "Input layer" ) ) );
+
+  addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Nodes" ) ) );
+}
+
+QVariantMap QgsExtractNodesAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
+{
+  std::unique_ptr< QgsFeatureSource > featureSource( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
+  if ( !featureSource )
+    return QVariantMap();
+
+  QgsWkbTypes::Type outputWkbType = QgsWkbTypes::Point;
+  if ( QgsWkbTypes::hasM( featureSource->wkbType() ) )
+  {
+    outputWkbType = QgsWkbTypes::addM( outputWkbType );
+  }
+  if ( QgsWkbTypes::hasZ( featureSource->wkbType() ) )
+  {
+    outputWkbType = QgsWkbTypes::addZ( outputWkbType );
+  }
+
+  QgsFields outputFields = featureSource->fields();
+  outputFields.append( QgsField( QStringLiteral( "node_index" ), QVariant::Int, QString(), 10, 0 ) );
+  outputFields.append( QgsField( QStringLiteral( "distance" ), QVariant::Double, QString(), 20, 6 ) );
+  outputFields.append( QgsField( QStringLiteral( "angle" ), QVariant::Double, QString(), 20, 6 ) );
+
+  QString dest;
+  std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, outputFields, outputWkbType, featureSource->sourceCrs() ) );
+  if ( !sink )
+    return QVariantMap();
+
+  double step = featureSource->featureCount() > 0 ? 100.0 / featureSource->featureCount() : 1;
+  QgsFeatureIterator it = featureSource->getFeatures( QgsFeatureRequest() );
+  QgsFeature f;
+  int i = -1;
+  while ( it.nextFeature( f ) )
+  {
+    i++;
+    if ( feedback->isCanceled() )
+    {
+      break;
+    }
+
+    QgsGeometry inputGeom = f.geometry();
+    if ( inputGeom.isNull() )
+    {
+      sink->addFeature( f, QgsFeatureSink::FastInsert );
+    }
+    else
+    {
+      const QgsCoordinateSequence sequence = inputGeom.constGet()->coordinateSequence();
+      for ( const QgsRingSequence &part : sequence )
+      {
+        int vertexPos = 0;
+        for ( const QgsPointSequence &ring : part )
+        {
+          for ( int j = 0; j < ring.count(); ++ j )
+          {
+            double distance = inputGeom.distanceToVertex( vertexPos );
+            double angle = inputGeom.angleAtVertex( vertexPos ) * 180 / M_PI_2;
+            QgsAttributes attrs = f.attributes();
+            attrs << vertexPos
+                  << distance
+                  << angle;
+            QgsFeature outputFeature = QgsFeature();
+            outputFeature.setAttributes( attrs );
+            outputFeature.setGeometry( QgsGeometry( ring.at( j ).clone() ) );
+            sink->addFeature( outputFeature, QgsFeatureSink::FastInsert );
+            vertexPos++;
+          }
+        }
+      }
+    }
+    feedback->setProgress( i * step );
+  }
+
+  QVariantMap outputs;
+  outputs.insert( QStringLiteral( "OUTPUT" ), dest );
+  return outputs;
+}
+
+///@endcond
diff --git a/src/analysis/processing/qgsalgorithmextractnodes.h b/src/analysis/processing/qgsalgorithmextractnodes.h
@@ -0,0 +1,56 @@
+/***************************************************************************
+                         qgsalgorithmextractnodes.h
+                         -------------------------
+    begin                : November 2017
+    copyright            : (C) 2017 by Mathieu Pellerin
+    email                : nirvn dot asia 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 QGSALGORITHMEXTRACTNODES_H
+#define QGSALGORITHMEXTRACTNODES_H
+
+#define SIP_NO_FILE
+
+#include "qgis.h"
+#include "qgsprocessingalgorithm.h"
+
+///@cond PRIVATE
+
+/**
+ * Native extract nodes algorithm.
+ */
+class QgsExtractNodesAlgorithm : public QgsProcessingAlgorithm
+{
+
+  public:
+
+    QgsExtractNodesAlgorithm() = default;
+    void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
+    QString name() const override;
+    QString displayName() const override;
+    virtual QStringList tags() const override;
+    QString group() const override;
+    QString shortHelpString() const override;
+    QgsExtractNodesAlgorithm *createInstance() const override SIP_FACTORY;
+
+  protected:
+
+    virtual QVariantMap processAlgorithm( const QVariantMap &parameters,
+                                          QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
+
+};
+
+///@endcond PRIVATE
+
+#endif // QGSALGORITHMEXTRACTNODES_H
+
+
diff --git a/src/analysis/processing/qgsnativealgorithms.cpp b/src/analysis/processing/qgsnativealgorithms.cpp
@@ -32,6 +32,7 @@
 #include "qgsalgorithmextractbyexpression.h"
 #include "qgsalgorithmextractbyextent.h"
 #include "qgsalgorithmextractbylocation.h"
+#include "qgsalgorithmextractnodes.h"
 #include "qgsalgorithmfiledownloader.h"
 #include "qgsalgorithmfixgeometries.h"
 #include "qgsalgorithmjoinbyattribute.h"
@@ -106,6 +107,7 @@ void QgsNativeAlgorithms::loadAlgorithms()
   addAlgorithm( new QgsExtractByExpressionAlgorithm() );
   addAlgorithm( new QgsExtractByExtentAlgorithm() );
   addAlgorithm( new QgsExtractByLocationAlgorithm() );
+  addAlgorithm( new QgsExtractNodesAlgorithm() );
   addAlgorithm( new QgsFileDownloaderAlgorithm() );
   addAlgorithm( new QgsFixGeometriesAlgorithm() );
   addAlgorithm( new QgsJoinByAttributeAlgorithm() );