Cleanup interpolation code

qgis · Nov 2, 2017 · f200d9c · f200d9c
1 parent cb292c1
commit f200d9c
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Showing 4 changed files with 104 additions and 54 deletions.
diff --git a/python/analysis/interpolation/qgsidwinterpolator.sip b/python/analysis/interpolation/qgsidwinterpolator.sip
@@ -11,25 +11,46 @@
 
 class QgsIDWInterpolator: QgsInterpolator
 {
+%Docstring
+ Inverse distance weight interpolator.
+%End
 
 %TypeHeaderCode
 #include "qgsidwinterpolator.h"
 %End
   public:
+
     QgsIDWInterpolator( const QList<QgsInterpolator::LayerData> &layerData );
+%Docstring
+ Constructor for QgsIDWInterpolator, with the specified ``layerData`` sources.
+%End
+
+    virtual int interpolatePoint( double x, double y, double &result, QgsFeedback *feedback = 0 );
 
-    virtual int interpolatePoint( double x, double y, double &result );
 
+    void setDistanceCoefficient( double coefficient );
 %Docstring
- 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
-:return: 0 in case of success*
- :rtype: int
+ Sets the distance ``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 ).
+
+.. seealso:: distanceCoefficient()
+.. versionadded:: 3.0
 %End
 
-    void setDistanceCoefficient( double p );
+    double distanceCoefficient() const;
+%Docstring
+ 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 ).
+
+.. seealso:: setDistanceCoefficient()
+.. versionadded:: 3.0
+ :rtype: float
+%End
 
 };
 

diff --git a/python/analysis/interpolation/qgsinterpolator.sip b/python/analysis/interpolation/qgsinterpolator.sip
@@ -10,63 +10,110 @@
 
 
 
-struct vertexData
+struct QgsInterpolatorVertexData
 {
+
+  QgsInterpolatorVertexData( double x, double y, double z );
+%Docstring
+ Constructor for QgsInterpolatorVertexData with the specified
+ ``x``, ``y``, and ``z`` coordinate.
+%End
+
+  QgsInterpolatorVertexData();
+%Docstring
+Constructor for QgsInterpolatorVertexData
+%End
+
   double x;
+%Docstring
+X-coordinate
+%End
   double y;
+%Docstring
+Y-coordinate
+%End
   double z;
+%Docstring
+Z-coordinate
+%End
 };
 
 class QgsInterpolator
 {
 %Docstring
  Interface class for interpolations. Interpolators take
-the vertices of a vector layer as base data. The z-Value
-can be an attribute or the z-coordinates in case of 25D types*
+ the vertices of a vector layer as base data. The z-Value
+ can be an attribute or the z-coordinates in case of 3D types.
 %End
 
 %TypeHeaderCode
 #include "qgsinterpolator.h"
 %End
   public:
-    enum InputType
+
+    enum SourceType
     {
-      POINTS,
-      STRUCTURE_LINES,
-      BREAK_LINES
+      SourcePoints,
+      SourceStructureLines,
+      SourceBreakLines,
+    };
+
+    enum Result
+    {
+      Success,
+      Canceled,
+      InvalidSource,
+      FeatureGeometryError,
     };
 
     struct LayerData
     {
-      QgsVectorLayer *vectorLayer;
-      bool zCoordInterpolation;
+      QgsFeatureSource *source;
+%Docstring
+Feature source
+%End
+      bool useZValue;
+%Docstring
+True if feature geometry z values should be used for interpolation
+%End
       int interpolationAttribute;
-      QgsInterpolator::InputType mInputType;
+%Docstring
+Index of feature attribute to use for interpolation
+%End
+      QgsInterpolator::SourceType sourceType;
+%Docstring
+Source type
+%End
     };
 
     QgsInterpolator( const QList<QgsInterpolator::LayerData> &layerData );
 
     virtual ~QgsInterpolator();
 
-    virtual int interpolatePoint( double x, double y, double &result ) = 0;
+    virtual int interpolatePoint( double x, double y, double &result, QgsFeedback *feedback = 0 ) = 0;
 %Docstring
  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
-:return: 0 in case of success*
+ \param x x-coordinate (in map units)
+ \param y y-coordinate (in map units)
+ \param result out: interpolation result
+ \param feedback optional feedback object for progress and cancelation support
+ :return: 0 in case of success*
  :rtype: int
 %End
 
 
   protected:
 
-    int cacheBaseData();
+    Result cacheBaseData( QgsFeedback *feedback = 0 );
 %Docstring
  Caches the vertex and value data from the provider. All the vertex data
-will be held in virtual memory
-:return: 0 in case of success*
- :rtype: int
+ will be held in virtual memory.
+
+ An optional ``feedback`` argument may be specified to allow cancelation and
+ progress reports from the cache operation.
+
+ :return: Success in case of success
+ :rtype: Result
 %End
 
 

diff --git a/python/analysis/interpolation/qgstininterpolator.sip b/python/analysis/interpolation/qgstininterpolator.sip
@@ -34,16 +34,8 @@ class QgsTINInterpolator: QgsInterpolator
 %End
     ~QgsTINInterpolator();
 
-    virtual int interpolatePoint( double x, double y, double &result );
+    virtual int interpolatePoint( double x, double y, double &result, QgsFeedback *feedback );
 
-%Docstring
- 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
-:return: 0 in case of success*
- :rtype: int
-%End
 
     static QgsFields triangulationFields();
 %Docstring

diff --git a/src/analysis/interpolation/qgsidwinterpolator.cpp b/src/analysis/interpolation/qgsidwinterpolator.cpp
@@ -16,20 +16,13 @@
  ***************************************************************************/
 
 #include "qgsidwinterpolator.h"
+#include "qgis.h"
 #include <cmath>
 #include <limits>
 
 QgsIDWInterpolator::QgsIDWInterpolator( const QList<LayerData> &layerData )
   : QgsInterpolator( layerData )
-{
-
-}
-
-QgsIDWInterpolator::QgsIDWInterpolator()
-  : QgsInterpolator( QList<LayerData>() )
-{
-
-}
+{}
 
 int QgsIDWInterpolator::interpolatePoint( double x, double y, double &result, QgsFeedback *feedback )
 {
@@ -38,22 +31,19 @@ int QgsIDWInterpolator::interpolatePoint( double x, double y, double &result, Qg
     cacheBaseData( feedback );
   }
 
-  double currentWeight;
-  double distance;
-
   double sumCounter = 0;
   double sumDenominator = 0;
 
-  Q_FOREACH ( const vertexData &vertex_it, mCachedBaseData )
+  for ( const QgsInterpolatorVertexData &vertex : qgis::as_const( mCachedBaseData ) )
   {
-    distance = std::sqrt( ( vertex_it.x - x ) * ( vertex_it.x - x ) + ( vertex_it.y - y ) * ( vertex_it.y - y ) );
-    if ( ( distance - 0 ) < std::numeric_limits<double>::min() )
+    double distance = std::sqrt( ( vertex.x - x ) * ( vertex.x - x ) + ( vertex.y - y ) * ( vertex.y - y ) );
+    if ( qgsDoubleNear( distance, 0.0 ) )
     {
-      result = vertex_it.z;
+      result = vertex.z;
       return 0;
     }
-    currentWeight = 1 / ( std::pow( distance, mDistanceCoefficient ) );
-    sumCounter += ( currentWeight * vertex_it.z );
+    double currentWeight = 1 / ( std::pow( distance, mDistanceCoefficient ) );
+    sumCounter += ( currentWeight * vertex.z );
     sumDenominator += currentWeight;
   }