[FEATURE] Allow band selection for zonal stats plugin

Author: nyalldawson

src/plugins/zonal_statistics/qgszonalstatisticsdialog.cpp

@@ -120,7 +120,7 @@ void QgsZonalStatisticsDialog::insertAvailableLayers()
       QgsRasterDataProvider* rp = rl->dataProvider();
       if ( rp && rp->name() == "gdal" )
       {
-        mRasterLayerComboBox->addItem( rl->name(), QVariant( rl->source() ) );
+        mRasterLayerComboBox->addItem( rl->name(), QVariant( rl->id() ) );
       }
     }
     else
@@ -138,14 +138,27 @@ void QgsZonalStatisticsDialog::insertAvailableLayers()
   }
 }
 
-QString QgsZonalStatisticsDialog::rasterFilePath() const
+QgsRasterLayer* QgsZonalStatisticsDialog::rasterLayer() const
 {
   int index = mRasterLayerComboBox->currentIndex();
   if ( index == -1 )
   {
-    return "";
+    return 0;
   }
-  return mRasterLayerComboBox->itemData( index ).toString();
+  QString id = mRasterLayerComboBox->itemData( index ).toString();
+  QgsRasterLayer* layer = dynamic_cast<QgsRasterLayer*>( QgsMapLayerRegistry::instance()->mapLayer( id ) );
+  return layer;
+}
+
+QString QgsZonalStatisticsDialog::rasterFilePath() const
+{
+  QgsRasterLayer* layer = rasterLayer();
+  return layer ? layer->source() : QString();
+}
+
+int QgsZonalStatisticsDialog::rasterBand() const
+{
+  return mBandComboBox->currentIndex() + 1;
 }
 
 QgsVectorLayer* QgsZonalStatisticsDialog::polygonLayer() const
@@ -171,7 +184,7 @@ QgsZonalStatistics::Statistics QgsZonalStatisticsDialog::selectedStats() const
     QListWidgetItem* item = mStatsListWidget->item( i );
     if ( item->checkState() == Qt::Checked )
     {
-      stats |= ( QgsZonalStatistics::Statistic )( item->data( Qt::UserRole ).toInt() );
+      stats |= ( QgsZonalStatistics::Statistic )item->data( Qt::UserRole ).toInt();
     }
   }
   return stats;
@@ -218,3 +231,24 @@ bool QgsZonalStatisticsDialog::prefixIsValid( const QString& prefix ) const
   }
   return true;
 }
+
+void QgsZonalStatisticsDialog::on_mRasterLayerComboBox_currentIndexChanged( int index )
+{
+  Q_UNUSED( index );
+
+  QgsRasterLayer* layer = rasterLayer();
+  if ( !layer )
+  {
+    mBandComboBox->setEnabled( false );
+    return;
+  }
+
+  mBandComboBox->setEnabled( true );
+  mBandComboBox->clear();
+
+  int bandCountInt = layer->bandCount();
+  for ( int i = 1; i <= bandCountInt; ++i )
+  {
+    mBandComboBox->addItem( layer->bandName( i ) );
+  }
+}

src/plugins/zonal_statistics/qgszonalstatisticsdialog.h

@@ -1,4 +1,4 @@
-/***************************************************************************
+/***************************************************************************
                           qgszonalstatisticsdialog.h  -  description
                              -----------------------
     begin                : September 1st, 2009
@@ -23,6 +23,7 @@
 
 class QgisInterface;
 class QgsVectorLayer;
+class QgsRasterLayer;
 
 class QgsZonalStatisticsDialog: public QDialog, private Ui::QgsZonalStatisticsDialogBase
 {
@@ -32,8 +33,10 @@ class QgsZonalStatisticsDialog: public QDialog, private Ui::QgsZonalStatisticsDi
     ~QgsZonalStatisticsDialog();
 
     QString rasterFilePath() const;
-    int rasterBand() const {return 1;} //todo: expose that in the GUI
+    int rasterBand() const;
     QgsVectorLayer* polygonLayer() const;
+    QgsRasterLayer* rasterLayer() const;
+
     QString attributePrefix() const;
     QgsZonalStatistics::Statistics selectedStats() const;
 
@@ -47,6 +50,11 @@ class QgsZonalStatisticsDialog: public QDialog, private Ui::QgsZonalStatisticsDi
     bool prefixIsValid( const QString& prefix ) const;
 
     QgisInterface* mIface;
+
+  private slots:
+
+    void on_mRasterLayerComboBox_currentIndexChanged( int index );
+
 };
 
 #endif // QGSZONALSTATISTICSDIALOG_H

src/plugins/zonal_statistics/qgszonalstatisticsdialogbase.ui

@@ -24,6 +24,20 @@
    <item>
     <widget class="QComboBox" name="mRasterLayerComboBox"/>
    </item>
+   <item>
+    <layout class="QHBoxLayout" name="horizontalLayout">
+     <item>
+      <widget class="QLabel" name="label_2">
+       <property name="text">
+        <string>Band</string>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <widget class="QComboBox" name="mBandComboBox"/>
+     </item>
+    </layout>
+   </item>
    <item>
     <widget class="QLabel" name="mVectorLayerLabel">
      <property name="text">
@@ -70,6 +84,14 @@
    </item>
   </layout>
  </widget>
+ <tabstops>
+  <tabstop>mRasterLayerComboBox</tabstop>
+  <tabstop>mBandComboBox</tabstop>
+  <tabstop>mPolygonLayerComboBox</tabstop>
+  <tabstop>mColumnPrefixLineEdit</tabstop>
+  <tabstop>mStatsListWidget</tabstop>
+  <tabstop>buttonBox</tabstop>
+ </tabstops>
  <resources/>
  <connections>
   <connection>

src/plugins/zonal_statistics/qgszonalstatisticsplugin.cpp

@@ -72,7 +72,7 @@ void QgsZonalStatisticsPlugin::run()
     return;
   }
 
-  QgsZonalStatistics zs( vl, rasterFile, d.attributePrefix(), 1, d.selectedStats() ); //atm hardcode first band
+  QgsZonalStatistics zs( vl, rasterFile, d.attributePrefix(), d.rasterBand(), d.selectedStats() );
   QProgressDialog p( tr( "Calculating zonal statistics..." ), tr( "Abort..." ), 0, 0 );
   p.setWindowModality( Qt::WindowModal );
   zs.calculateStatistics( &p );