Use double rather than float when appropriate to improve precision of…

… heatmaps
qgis · Mar 13, 2013 · 239479a · 239479a
1 parent 3b8cbc2
commit 239479a
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Showing 4 changed files with 29 additions and 29 deletions.
diff --git a/src/plugins/heatmap/heatmap.cpp b/src/plugins/heatmap/heatmap.cpp
@@ -107,8 +107,8 @@ void Heatmap::run()
     QgsRectangle myBBox = d.bbox();
     int columns = d.columns();
     int rows = d.rows();
-    float cellsize = d.cellSizeX(); // or d.cellSizeY();  both have the same value
-    float myDecay = d.decayRatio();
+    double cellsize = d.cellSizeX(); // or d.cellSizeY();  both have the same value
+    double myDecay = d.decayRatio();
 
     // Start working on the input vector
     QgsVectorLayer* inputLayer = d.inputVectorLayer();
@@ -164,8 +164,8 @@ void Heatmap::run()
     int wField = 0;
 
     // Handle different radius options
-    float radius;
-    float radiusToMapUnits = 1;
+    double radius;
+    double radiusToMapUnits = 1;
     int myBuffer;
     if ( d.variableRadius() )
     {
@@ -226,7 +226,7 @@ void Heatmap::run()
       // If radius is variable then fetch it and calculate new pixel buffer size
       if ( d.variableRadius() )
       {
-        radius = myFeature.attribute( rField ).toFloat() * radiusToMapUnits;
+        radius = myFeature.attribute( rField ).toDouble() * radiusToMapUnits;
         myBuffer = bufferSize( radius, cellsize );
       }
 
@@ -241,25 +241,25 @@ void Heatmap::run()
       poBand->RasterIO( GF_Read, xPosition, yPosition, blockSize, blockSize,
                         dataBuffer, blockSize, blockSize, GDT_Float32, 0, 0 );
 
-      float weight = 1.0;
+      double weight = 1.0;
       if ( d.weighted() )
       {
-        weight = myFeature.attribute( wField ).toFloat();
+        weight = myFeature.attribute( wField ).toDouble();
       }
 
       for ( int xp = 0; xp <= myBuffer; xp++ )
       {
         for ( int yp = 0; yp <= myBuffer; yp++ )
         {
-          float distance = sqrt( pow( xp, 2.0 ) + pow( yp, 2.0 ) );
+          double distance = sqrt( pow( xp, 2.0 ) + pow( yp, 2.0 ) );
 
           // is pixel outside search bandwidth of feature?
           if ( distance > myBuffer )
           {
             continue;
           }
 
-          float pixelValue = weight * ( 1 - (( 1 - myDecay ) * distance / myBuffer ) );
+          double pixelValue = weight * ( 1 - (( 1 - myDecay ) * distance / myBuffer ) );
 
           // clearing anamolies along the axes
           if ( xp == 0 && yp == 0 )
@@ -305,7 +305,7 @@ void Heatmap::run()
  *
  */
 
-float Heatmap::mapUnitsOf( float meters, QgsCoordinateReferenceSystem layerCrs )
+double Heatmap::mapUnitsOf( double meters, QgsCoordinateReferenceSystem layerCrs )
 {
   // Worker to transform metres input to mapunits
   QgsDistanceArea da;
@@ -318,7 +318,7 @@ float Heatmap::mapUnitsOf( float meters, QgsCoordinateReferenceSystem layerCrs )
   return meters / da.measureLine( QgsPoint( 0.0, 0.0 ), QgsPoint( 0.0, 1.0 ) );
 }
 
-int Heatmap::bufferSize( float radius, float cellsize )
+int Heatmap::bufferSize( double radius, double cellsize )
 {
   // Calculate the buffer size in pixels
 

diff --git a/src/plugins/heatmap/heatmap.h b/src/plugins/heatmap/heatmap.h
@@ -82,9 +82,9 @@ class Heatmap: public QObject, public QgisPlugin
 
   private:
     //! Worker to convert meters to map units
-    float mapUnitsOf( float meters, QgsCoordinateReferenceSystem crs );
+    double mapUnitsOf( double meters, QgsCoordinateReferenceSystem layerCrs );
     //! Worker to calculate buffer size in pixels
-    int bufferSize( float radius, float cellsize );
+    int bufferSize( double radius, double cellsize );
 
     // MANDATORY PLUGIN PROPERTY DECLARATIONS  .....
 

diff --git a/src/plugins/heatmap/heatmapgui.cpp b/src/plugins/heatmap/heatmapgui.cpp
@@ -170,7 +170,7 @@ void HeatmapGui::on_columnLineEdit_editingFinished()
 
 void HeatmapGui::on_cellXLineEdit_editingFinished()
 {
-  mXcellsize = cellXLineEdit->text().toFloat();
+  mXcellsize = cellXLineEdit->text().toDouble();
   mYcellsize = mXcellsize;
   mRows = mBBox.height() / mYcellsize + 1;
   mColumns = mBBox.width() / mXcellsize + 1;
@@ -180,7 +180,7 @@ void HeatmapGui::on_cellXLineEdit_editingFinished()
 
 void HeatmapGui::on_cellYLineEdit_editingFinished()
 {
-  mYcellsize = cellYLineEdit->text().toFloat();
+  mYcellsize = cellYLineEdit->text().toDouble();
   mXcellsize = mYcellsize;
   mRows = mBBox.height() / mYcellsize + 1;
   mColumns = mBBox.width() / mXcellsize + 1;
@@ -281,10 +281,10 @@ void HeatmapGui::updateBBox()
   mBBox = inputLayer->extent();
   QgsCoordinateReferenceSystem layerCrs = inputLayer->crs();
 
-  float radiusInMapUnits = 0.0;
+  double radiusInMapUnits = 0.0;
   if ( useRadius->isChecked() )
   {
-    float maxInField = inputLayer->maximumValue( radiusFieldCombo->itemData( radiusFieldCombo->currentIndex() ).toInt() ).toFloat();
+    double maxInField = inputLayer->maximumValue( radiusFieldCombo->itemData( radiusFieldCombo->currentIndex() ).toInt() ).toDouble();
 
     if ( radiusFieldUnitCombo->currentIndex() == HeatmapGui::Meters )
     {
@@ -297,7 +297,7 @@ void HeatmapGui::updateBBox()
   }
   else
   {
-    float radiusValue = mBufferLineEdit->text().toFloat();
+    double radiusValue = mBufferLineEdit->text().toDouble();
     if ( mRadiusUnitCombo->currentIndex() == HeatmapGui::Meters )
     {
       radiusInMapUnits = mapUnitsOf( radiusValue, layerCrs );
@@ -325,7 +325,7 @@ void HeatmapGui::updateBBox()
   }
 }
 
-float HeatmapGui::mapUnitsOf( float meters, QgsCoordinateReferenceSystem layerCrs )
+double HeatmapGui::mapUnitsOf( double meters, QgsCoordinateReferenceSystem layerCrs )
 {
   // converter function to transform metres input to mapunits
   // so that bounding box can be updated
@@ -356,9 +356,9 @@ bool HeatmapGui::variableRadius()
   return useRadius->isChecked();
 }
 
-float HeatmapGui::radius()
+double HeatmapGui::radius()
 {
-  float radius = mBufferLineEdit->text().toFloat();
+  double radius = mBufferLineEdit->text().toDouble();
   if ( mRadiusUnitCombo->currentIndex() == HeatmapGui::Meters )
   {
     radius = mapUnitsOf( radius, inputVectorLayer()->crs() );
@@ -375,9 +375,9 @@ int HeatmapGui::radiusUnit()
   return mRadiusUnitCombo->currentIndex();
 }
 
-float HeatmapGui::decayRatio()
+double HeatmapGui::decayRatio()
 {
-  return mDecayLineEdit->text().toFloat();
+  return mDecayLineEdit->text().toDouble();
 }
 
 int HeatmapGui::radiusField()

diff --git a/src/plugins/heatmap/heatmapgui.h b/src/plugins/heatmap/heatmapgui.h
@@ -43,13 +43,13 @@ class HeatmapGui : public QDialog, private Ui::HeatmapGuiBase
     bool variableRadius();
 
     /** Returns the fixed radius value */
-    float radius();
+    double radius();
 
     /** Return the radius Unit (meters/map units) */
     int radiusUnit();
 
     /** Return the decay ratio */
-    float decayRatio();
+    double decayRatio();
 
     /** Return the attribute field for variable radius */
     int radiusField();
@@ -73,10 +73,10 @@ class HeatmapGui : public QDialog, private Ui::HeatmapGuiBase
     int columns() { return mColumns; }
 
     /** Returns the cell size X value */
-    float cellSizeX() { return mXcellsize; }
+    double cellSizeX() { return mXcellsize; }
 
     /** Returns the cell size Y valuue */
-    float cellSizeY() { return mYcellsize; }
+    double cellSizeY() { return mYcellsize; }
 
     /** Return the BBox */
     QgsRectangle bbox() { return mBBox; }
@@ -86,7 +86,7 @@ class HeatmapGui : public QDialog, private Ui::HeatmapGuiBase
 
     // bbox of layer for lineedit changes
     QgsRectangle mBBox;
-    float mXcellsize, mYcellsize;
+    double mXcellsize, mYcellsize;
     int mRows, mColumns;
 
     /** Function to check wether all constrains are satisfied and enable the OK button */
@@ -102,7 +102,7 @@ class HeatmapGui : public QDialog, private Ui::HeatmapGuiBase
     void updateSize();
 
     /** Convert Maters value to the corresponding map units based on Layer projection */
-    float mapUnitsOf( float meters, QgsCoordinateReferenceSystem layerCrs );
+    double mapUnitsOf( double meters, QgsCoordinateReferenceSystem layerCrs );
 
   private slots:
     void on_mButtonBox_accepted();