[FEATURE] Add extra resampling methods to align raster tool which are

available in GDAL >= 2.0 (max, min, median, q1 and q3)

Author: nyalldawson

python/analysis/raster/qgsalignraster.sip

@@ -3,6 +3,7 @@ class QgsAlignRaster
 {
 %TypeHeaderCode
 #include <qgsalignraster.h>
+#include <gdal_version.h>
 %End
 
   public:
@@ -47,15 +48,21 @@ class QgsAlignRaster
 
 
     //! Resampling algorithm to be used (equivalent to GDAL's enum GDALResampleAlg)
+    //! @note RA_Max, RA_Min, RA_Median, RA_Q1 and RA_Q3 are available on GDAL >= 2.0 builds only
     enum ResampleAlg
     {
-      RA_NearestNeighbour = 0, //!< Nearest neighbour (select on one input pixel)
-      RA_Bilinear = 1,       //!< Bilinear (2x2 kernel)
-      RA_Cubic = 2,          //!< Cubic Convolution Approximation (4x4 kernel)
-      RA_CubicSpline = 3,    //!< Cubic B-Spline Approximation (4x4 kernel)
-      RA_Lanczos = 4,        //!< Lanczos windowed sinc interpolation (6x6 kernel)
-      RA_Average = 5,        //!< Average (computes the average of all non-NODATA contributing pixels)
-      RA_Mode = 6            //!< Mode (selects the value which appears most often of all the sampled points)
+      RA_NearestNeighbour, //!< Nearest neighbour (select on one input pixel)
+      RA_Bilinear,       //!< Bilinear (2x2 kernel)
+      RA_Cubic,          //!< Cubic Convolution Approximation (4x4 kernel)
+      RA_CubicSpline,    //!< Cubic B-Spline Approximation (4x4 kernel)
+      RA_Lanczos,        //!< Lanczos windowed sinc interpolation (6x6 kernel)
+      RA_Average,        //!< Average (computes the average of all non-NODATA contributing pixels)
+      RA_Mode,            //!< Mode (selects the value which appears most often of all the sampled points)
+      RA_Max, //!< Maximum (selects the maximum of all non-NODATA contributing pixels)
+      RA_Min, //!< Minimum (selects the minimum of all non-NODATA contributing pixels)
+      RA_Median, //!< Median (selects the median of all non-NODATA contributing pixels)
+      RA_Q1, //!< First quartile (selects the first quartile of all non-NODATA contributing pixels)
+      RA_Q3, //!< Third quartile (selects the third quartile of all non-NODATA contributing pixels)
     };
 
     //! Definition of one raster layer for alignment

src/analysis/raster/qgsalignraster.h

@@ -20,6 +20,7 @@
 #include <QPointF>
 #include <QSizeF>
 #include <QString>
+#include <gdal_version.h>
 
 class QgsRectangle;
 
@@ -94,6 +95,7 @@ class ANALYSIS_EXPORT QgsAlignRaster
 
 
     //! Resampling algorithm to be used (equivalent to GDAL's enum GDALResampleAlg)
+    //! @note RA_Max, RA_Min, RA_Median, RA_Q1 and RA_Q3 are available on GDAL >= 2.0 builds only
     enum ResampleAlg
     {
       RA_NearestNeighbour = 0, //!< Nearest neighbour (select on one input pixel)
@@ -102,7 +104,12 @@ class ANALYSIS_EXPORT QgsAlignRaster
       RA_CubicSpline = 3,    //!< Cubic B-Spline Approximation (4x4 kernel)
       RA_Lanczos = 4,        //!< Lanczos windowed sinc interpolation (6x6 kernel)
       RA_Average = 5,        //!< Average (computes the average of all non-NODATA contributing pixels)
-      RA_Mode = 6            //!< Mode (selects the value which appears most often of all the sampled points)
+      RA_Mode = 6,            //!< Mode (selects the value which appears most often of all the sampled points)
+      RA_Max = 8, //!< Maximum (selects the maximum of all non-NODATA contributing pixels)
+      RA_Min = 9, //!< Minimum (selects the minimum of all non-NODATA contributing pixels)
+      RA_Median = 10, //!< Median (selects the median of all non-NODATA contributing pixels)
+      RA_Q1 = 11, //!< First quartile (selects the first quartile of all non-NODATA contributing pixels)
+      RA_Q3 = 12, //!< Third quartile (selects the third quartile of all non-NODATA contributing pixels)
     };
 
     //! Definition of one raster layer for alignment

src/app/qgsalignrasterdialog.cpp

@@ -239,7 +239,7 @@ void QgsAlignRasterDialog::addLayer()
   QgsAlignRaster::List list = mAlign->rasters();
 
   QgsAlignRaster::Item item( d.inputFilename(), d.outputFilename() );
-  item.resampleMethod = ( QgsAlignRaster::ResampleAlg ) d.resampleMethod();
+  item.resampleMethod = d.resampleMethod();
   item.rescaleValues = d.rescaleValues();
   list.append( item );
 
@@ -276,7 +276,7 @@ void QgsAlignRasterDialog::editLayer()
     return;
 
   QgsAlignRaster::Item itemNew( d.inputFilename(), d.outputFilename() );
-  itemNew.resampleMethod = ( QgsAlignRaster::ResampleAlg ) d.resampleMethod();
+  itemNew.resampleMethod = d.resampleMethod();
   itemNew.rescaleValues = d.rescaleValues();
   list[current.row()] = itemNew;
   mAlign->setRasters( list );
@@ -386,11 +386,20 @@ QgsAlignRasterLayerConfigDialog::QgsAlignRasterLayerConfigDialog()
   cboLayers->setFilters( QgsMapLayerProxyModel::RasterLayer );
 
   cboResample = new QComboBox( this );
-  QStringList methods;
-  methods << tr( "Nearest neighbour" ) << tr( "Bilinear (2x2 kernel)" )
-  << tr( "Cubic (4x4 kernel)" ) << tr( "Cubic B-Spline (4x4 kernel)" ) << tr( "Lanczos (6x6 kernel)" )
-  << tr( "Average" ) << tr( "Mode" );
-  cboResample->addItems( methods );
+  cboResample->addItem( tr( "Nearest neighbour" ), QgsAlignRaster::RA_NearestNeighbour );
+  cboResample->addItem( tr( "Bilinear (2x2 kernel)" ), QgsAlignRaster::RA_Bilinear );
+  cboResample->addItem( tr( "Cubic (4x4 kernel)" ), QgsAlignRaster::RA_Cubic );
+  cboResample->addItem( tr( "Cubic B-Spline (4x4 kernel)" ), QgsAlignRaster::RA_CubicSpline );
+  cboResample->addItem( tr( "Lanczos (6x6 kernel)" ), QgsAlignRaster::RA_Lanczos );
+  cboResample->addItem( tr( "Average" ), QgsAlignRaster::RA_Average );
+  cboResample->addItem( tr( "Mode" ), QgsAlignRaster::RA_Mode );
+#if defined(GDAL_VERSION_NUM) && GDAL_VERSION_NUM >= 2000000
+  cboResample->addItem( tr( "Maximum" ), QgsAlignRaster::RA_Max );
+  cboResample->addItem( tr( "Minimum" ), QgsAlignRaster::RA_Min );
+  cboResample->addItem( tr( "Median" ), QgsAlignRaster::RA_Median );
+  cboResample->addItem( tr( "First Quartile (Q1)" ), QgsAlignRaster::RA_Q1 );
+  cboResample->addItem( tr( "Third Quartile (Q3)" ), QgsAlignRaster::RA_Q3 );
+#endif
 
   editOutput = new QLineEdit( this );
   btnBrowse = new QPushButton( tr( "Browse..." ), this );
@@ -428,9 +437,9 @@ QString QgsAlignRasterLayerConfigDialog::outputFilename() const
   return editOutput->text();
 }
 
-int QgsAlignRasterLayerConfigDialog::resampleMethod() const
+QgsAlignRaster::ResampleAlg QgsAlignRasterLayerConfigDialog::resampleMethod() const
 {
-  return cboResample->currentIndex();
+  return static_cast< QgsAlignRaster::ResampleAlg >( cboResample->itemData( cboResample->currentIndex() ).toInt() );
 }
 
 bool QgsAlignRasterLayerConfigDialog::rescaleValues() const
@@ -439,11 +448,11 @@ bool QgsAlignRasterLayerConfigDialog::rescaleValues() const
 }
 
 void QgsAlignRasterLayerConfigDialog::setItem( const QString& inputFilename, const QString& outputFilename,
-    int resampleMethod, bool rescaleValues )
+    QgsAlignRaster::ResampleAlg resampleMethod, bool rescaleValues )
 {
   cboLayers->setLayer( _rasterLayer( inputFilename ) );
   editOutput->setText( outputFilename );
-  cboResample->setCurrentIndex( resampleMethod );
+  cboResample->setCurrentIndex( cboResample->findData( resampleMethod ) );
   chkRescale->setChecked( rescaleValues );
 }
 

src/app/qgsalignrasterdialog.h

@@ -16,7 +16,7 @@
 #define QGSALIGNRASTERDIALOG_H
 
 #include <QDialog>
-
+#include "qgsalignraster.h"
 #include "ui_qgsalignrasterdialog.h"
 
 class QgsAlignRaster;
@@ -71,10 +71,10 @@ class QgsAlignRasterLayerConfigDialog : public QDialog
 
     QString inputFilename() const;
     QString outputFilename() const;
-    int resampleMethod() const;
+    QgsAlignRaster::ResampleAlg resampleMethod() const;
     bool rescaleValues() const;
 
-    void setItem( const QString& inputFilename, const QString& outputFilename, int resampleMethod, bool rescaleValues );
+    void setItem( const QString& inputFilename, const QString& outputFilename, QgsAlignRaster::ResampleAlg resampleMethod, bool rescaleValues );
 
   protected slots:
     void browseOutputFilename();