Use QgsFeatureSources instead of QgsVectorLayer for interpolation

source layers
qgis · Nov 2, 2017 · b369ef8 · b369ef8
1 parent 28ee440
commit b369ef8
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Showing 5 changed files with 64 additions and 41 deletions.
diff --git a/src/analysis/interpolation/qgsgridfilewriter.cpp b/src/analysis/interpolation/qgsgridfilewriter.cpp
@@ -87,8 +87,8 @@ int QgsGridFileWriter::writeFile( QgsFeedback *feedback )
   // create prj file
   QgsInterpolator::LayerData ld;
   ld = mInterpolator->layerData().at( 0 );
-  QgsVectorLayer *vl = ld.vectorLayer;
-  QString crs = vl->crs().toWkt();
+  QgsFeatureSource *source = ld.source;
+  QString crs = source->sourceCrs().toWkt();
   QFileInfo fi( mOutputFilePath );
   QString fileName = fi.absolutePath() + '/' + fi.completeBaseName() + ".prj";
   QFile prjFile( fileName );

diff --git a/src/analysis/interpolation/qgsidwinterpolator.h b/src/analysis/interpolation/qgsidwinterpolator.h
@@ -24,32 +24,46 @@
 /**
  * \ingroup analysis
  * \class QgsIDWInterpolator
+ * Inverse distance weight interpolator.
  */
 class ANALYSIS_EXPORT QgsIDWInterpolator: public QgsInterpolator
 {
   public:
+
+    /**
+     * Constructor for QgsIDWInterpolator, with the specified \a layerData sources.
+     */
     QgsIDWInterpolator( const QList<QgsInterpolator::LayerData> &layerData );
 
     int interpolatePoint( double x, double y, double &result, QgsFeedback *feedback = nullptr ) override;
 
     /**
-     * Calculates interpolation value for map coordinates x, y
-       \param x x-coordinate (in map units)
-       \param y y-coordinate (in map units)
-       \param result out: interpolation result
-       \returns 0 in case of success*/
-    int interpolatePoint( double x, double y, double &result ) override;
+     * Sets the distance \a coefficient, the parameter that sets how the values are
+     * weighted with distance. Smaller values mean sharper peaks at the data points.
+     *
+     * Point values are weighted by 1 / ( distance ^ coefficient ).
+     *
+     * \see distanceCoefficient()
+     * \since QGIS 3.0
+    */
+    void setDistanceCoefficient( double coefficient ) { mDistanceCoefficient = coefficient;}
 
-    void setDistanceCoefficient( double p ) {mDistanceCoefficient = p;}
+    /**
+     * Returns the distance coefficient, the parameter that sets how the values are
+     * weighted with distance. Smaller values mean sharper peaks at the data points.
+     * The default is a coefficient of 2.
+     *
+     * Point values are weighted by 1 / ( distance ^ coefficient ).
+     *
+     * \see setDistanceCoefficient()
+     * \since QGIS 3.0
+    */
+    double distanceCoefficient() const { return mDistanceCoefficient; }
 
   private:
 
-    QgsIDWInterpolator(); //forbidden
+    QgsIDWInterpolator() = delete;
 
-    /**
-     * The parameter that sets how the values are weighted with distance.
-       Smaller values mean sharper peaks at the data points. The default is a
-       value of 2*/
     double mDistanceCoefficient = 2.0;
 };
 

diff --git a/src/analysis/interpolation/qgsinterpolator.cpp b/src/analysis/interpolation/qgsinterpolator.cpp
@@ -39,29 +39,30 @@ QgsInterpolator::Result QgsInterpolator::cacheBaseData( QgsFeedback *feedback )
   mCachedBaseData.clear();
   mCachedBaseData.reserve( 100000 );
 
-  Q_FOREACH ( const LayerData &layer, mLayerData )
+  double layerStep = !mLayerData.empty() ? 100.0 / mLayerData.count() : 1;
+  int layerCount = 0;
+  for ( const LayerData &layer : qgis::as_const( mLayerData ) )
   {
     if ( feedback && feedback->isCanceled() )
       return Canceled;
 
-    QgsVectorLayer *vlayer = layer.vectorLayer;
-    if ( !vlayer )
+    QgsFeatureSource *source = layer.source;
+    if ( !source )
     {
       return 2;
     }
 
     QgsAttributeList attList;
-    if ( !layer.zCoordInterpolation )
+    if ( !layer.useZValue )
     {
       attList.push_back( layer.interpolationAttribute );
     }
 
-
     double attributeValue = 0.0;
     bool attributeConversionOk = false;
     double progress = layerCount * layerStep;
 
-    QgsFeatureIterator fit = vlayer->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( attList ) );
+    QgsFeatureIterator fit = source->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( attList ) );
     double featureStep = source->featureCount() > 0 ? layerStep / source->featureCount() : layerStep;
 
     QgsFeature feature;
@@ -74,7 +75,7 @@ QgsInterpolator::Result QgsInterpolator::cacheBaseData( QgsFeedback *feedback )
       if ( feedback )
         feedback->setProgress( progress );
 
-      if ( !layer.zCoordInterpolation )
+      if ( !layer.useZValue )
       {
         QVariant attributeVariant = feature.attribute( layer.interpolationAttribute );
         if ( !attributeVariant.isValid() ) //attribute not found, something must be wrong (e.g. NULL value)
@@ -88,11 +89,10 @@ QgsInterpolator::Result QgsInterpolator::cacheBaseData( QgsFeedback *feedback )
         }
       }
 
-      if ( addVerticesToCache( feature.geometry(), layer.zCoordInterpolation, attributeValue ) != 0 )
-      {
-        return 3;
-      }
+      if ( !addVerticesToCache( feature.geometry(), layer.useZValue, attributeValue ) )
+        return FeatureGeometryError;
     }
+    layerCount++;
   }
 
   return 0;

diff --git a/src/analysis/interpolation/qgsinterpolator.h b/src/analysis/interpolation/qgsinterpolator.h
@@ -22,7 +22,7 @@
 #include "qgis_sip.h"
 #include "qgis_analysis.h"
 
-class QgsVectorLayer;
+class QgsFeatureSource;
 class QgsGeometry;
 class QgsFeedback;
 
@@ -58,9 +58,12 @@ class ANALYSIS_EXPORT QgsInterpolator
     //! A layer together with the information about interpolation attribute / z-coordinate interpolation and the type (point, structure line, breakline)
     struct LayerData
     {
-      QgsVectorLayer *vectorLayer = nullptr;
-      bool zCoordInterpolation;
-      int interpolationAttribute;
+      //! Feature source
+      QgsFeatureSource *source = nullptr;
+      //! True if feature geometry z values should be used for interpolation
+      bool useZValue = false;
+      //! Index of feature attribute to use for interpolation
+      int interpolationAttribute = -1;
       //! Source type
       QgsInterpolator::SourceType sourceType = SourcePoints;
     };
@@ -85,16 +88,22 @@ class ANALYSIS_EXPORT QgsInterpolator
 
     /**
      * Caches the vertex and value data from the provider. All the vertex data
-     will be held in virtual memory
-    \returns 0 in case of success*/
-    int cacheBaseData();
-
-    QVector<vertexData> mCachedBaseData;
+     * will be held in virtual memory.
+     *
+     * An optional \a feedback argument may be specified to allow cancelation and
+     * progress reports from the cache operation.
+     *
+     * \returns Success in case of success
+    */
+    Result cacheBaseData( QgsFeedback *feedback = nullptr );
+
+    //! Cached vertex data for input sources
+    QVector<QgsInterpolatorVertexData> mCachedBaseData;
 
     //! Flag that tells if the cache already has been filled
     bool mDataIsCached = false;
 
-    //Information about the input vector layers and the attributes (or z-values) that are used for interpolation
+    //! Information about the input vector layers and the attributes (or z-values) that are used for interpolation
     QList<LayerData> mLayerData;
 
   private:

diff --git a/src/analysis/interpolation/qgstininterpolator.cpp b/src/analysis/interpolation/qgstininterpolator.cpp
@@ -95,25 +95,25 @@ void QgsTINInterpolator::initialize()
   {
     Q_FOREACH ( const LayerData &layer, mLayerData )
     {
-      if ( layer.vectorLayer )
+      if ( layer.source )
       {
-        nFeatures += layer.vectorLayer->featureCount();
+        nFeatures += layer.source->featureCount();
       }
     }
   }
 
   QgsFeature f;
   Q_FOREACH ( const LayerData &layer, mLayerData )
   {
-    if ( layer.vectorLayer )
+    if ( layer.source )
     {
       QgsAttributeList attList;
-      if ( !layer.zCoordInterpolation )
+      if ( !layer.useZValue )
       {
         attList.push_back( layer.interpolationAttribute );
       }
 
-      QgsFeatureIterator fit = layer.vectorLayer->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( attList ) );
+      QgsFeatureIterator fit = layer.source->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( attList ) );
 
       while ( fit.nextFeature( f ) )
       {
@@ -126,7 +126,7 @@ void QgsTINInterpolator::initialize()
           if ( nFeatures > 0 )
             mFeedback->setProgress( 100.0 * static_cast< double >( nProcessedFeatures ) / nFeatures );
         }
-        insertData( &f, layer.zCoordInterpolation, layer.interpolationAttribute, layer.mInputType );
+        insertData( &f, layer.useZValue, layer.interpolationAttribute, layer.sourceType );
         ++nProcessedFeatures;
       }
     }