int QgsZonalStatistics::calculateStatistics( QProgressDialog* p )
{
if ( !mPolygonLayer || mPolygonLayer->geometryType() != QGis::Polygon )
{
return 1;
}
QgsVectorDataProvider* vectorProvider = mPolygonLayer->dataProvider();
if ( !vectorProvider )
{
return 2;
}
//open the raster layer and the raster band
GDALAllRegister();
GDALDatasetH inputDataset = GDALOpen( TO8F( mRasterFilePath ), GA_ReadOnly );
if ( !inputDataset )
{
return 3;
}
if ( GDALGetRasterCount( inputDataset ) < ( mRasterBand - 1 ) )
{
GDALClose( inputDataset );
return 4;
}
GDALRasterBandH rasterBand = GDALGetRasterBand( inputDataset, mRasterBand );
if ( !rasterBand )
{
GDALClose( inputDataset );
return 5;
}
mInputNodataValue = GDALGetRasterNoDataValue( rasterBand, nullptr );
//get geometry info about raster layer
int nCellsXGDAL = GDALGetRasterXSize( inputDataset );
int nCellsYGDAL = GDALGetRasterYSize( inputDataset );
double geoTransform[6];
if ( GDALGetGeoTransform( inputDataset, geoTransform ) != CE_None )
{
GDALClose( inputDataset );
return 6;
}
double cellsizeX = geoTransform[1];
if ( cellsizeX < 0 )
{
cellsizeX = -cellsizeX;
}
double cellsizeY = geoTransform[5];
if ( cellsizeY < 0 )
{
cellsizeY = -cellsizeY;
}
QgsRectangle rasterBBox( geoTransform[0], geoTransform[3] - ( nCellsYGDAL * cellsizeY ),
geoTransform[0] + ( nCellsXGDAL * cellsizeX ), geoTransform[3] );
//add the new fields to the provider
QList<QgsField> newFieldList;
QString countFieldName;
if ( mStatistics & QgsZonalStatistics::Count )
{
countFieldName = getUniqueFieldName( mAttributePrefix + "count" );
QgsField countField( countFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( countField );
}
QString sumFieldName;
if ( mStatistics & QgsZonalStatistics::Sum )
{
sumFieldName = getUniqueFieldName( mAttributePrefix + "sum" );
QgsField sumField( sumFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( sumField );
}
QString meanFieldName;
if ( mStatistics & QgsZonalStatistics::Mean )
{
meanFieldName = getUniqueFieldName( mAttributePrefix + "mean" );
QgsField meanField( meanFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( meanField );
}
QString medianFieldName;
if ( mStatistics & QgsZonalStatistics::Median )
{
medianFieldName = getUniqueFieldName( mAttributePrefix + "median" );
QgsField medianField( medianFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( medianField );
}
QString stdevFieldName;
if ( mStatistics & QgsZonalStatistics::StDev )
{
stdevFieldName = getUniqueFieldName( mAttributePrefix + "stdev" );
QgsField stdField( stdevFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( stdField );
}
QString minFieldName;
if ( mStatistics & QgsZonalStatistics::Min )
{
minFieldName = getUniqueFieldName( mAttributePrefix + "min" );
QgsField minField( minFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( minField );
}
QString maxFieldName;
if ( mStatistics & QgsZonalStatistics::Max )
{
maxFieldName = getUniqueFieldName( mAttributePrefix + "max" );
QgsField maxField( maxFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( maxField );
}
QString rangeFieldName;
if ( mStatistics & QgsZonalStatistics::Range )
{
rangeFieldName = getUniqueFieldName( mAttributePrefix + "range" );
QgsField rangeField( rangeFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( rangeField );
}
QString minorityFieldName;
if ( mStatistics & QgsZonalStatistics::Minority )
{
minorityFieldName = getUniqueFieldName( mAttributePrefix + "minority" );
QgsField minorityField( minorityFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( minorityField );
}
QString majorityFieldName;
if ( mStatistics & QgsZonalStatistics::Majority )
{
majorityFieldName = getUniqueFieldName( mAttributePrefix + "majority" );
QgsField majField( majorityFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( majField );
}
QString varietyFieldName;
if ( mStatistics & QgsZonalStatistics::Variety )
{
varietyFieldName = getUniqueFieldName( mAttributePrefix + "variety" );
QgsField varietyField( varietyFieldName, QVariant::Int, "int" );
newFieldList.push_back( varietyField );
}
vectorProvider->addAttributes( newFieldList );
//index of the new fields
int countIndex = mStatistics & QgsZonalStatistics::Count ? vectorProvider->fieldNameIndex( countFieldName ) : -1;
int sumIndex = mStatistics & QgsZonalStatistics::Sum ? vectorProvider->fieldNameIndex( sumFieldName ) : -1;
int meanIndex = mStatistics & QgsZonalStatistics::Mean ? vectorProvider->fieldNameIndex( meanFieldName ) : -1;
int medianIndex = mStatistics & QgsZonalStatistics::Median ? vectorProvider->fieldNameIndex( medianFieldName ) : -1;
int stdevIndex = mStatistics & QgsZonalStatistics::StDev ? vectorProvider->fieldNameIndex( stdevFieldName ) : -1;
int minIndex = mStatistics & QgsZonalStatistics::Min ? vectorProvider->fieldNameIndex( minFieldName ) : -1;
int maxIndex = mStatistics & QgsZonalStatistics::Max ? vectorProvider->fieldNameIndex( maxFieldName ) : -1;
int rangeIndex = mStatistics & QgsZonalStatistics::Range ? vectorProvider->fieldNameIndex( rangeFieldName ) : -1;
int minorityIndex = mStatistics & QgsZonalStatistics::Minority ? vectorProvider->fieldNameIndex( minorityFieldName ) : -1;
int majorityIndex = mStatistics & QgsZonalStatistics::Majority ? vectorProvider->fieldNameIndex( majorityFieldName ) : -1;
int varietyIndex = mStatistics & QgsZonalStatistics::Variety ? vectorProvider->fieldNameIndex( varietyFieldName ) : -1;
if (( mStatistics & QgsZonalStatistics::Count && countIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Sum && sumIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Mean && meanIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Median && medianIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::StDev && stdevIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Min && minIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Max && maxIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Range && rangeIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Minority && minorityIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Majority && majorityIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Variety && varietyIndex == -1 )
)
{
//failed to create a required field
return 8;
}
//progress dialog
long featureCount = vectorProvider->featureCount();
if ( p )
{
p->setMaximum( featureCount );
}
//iterate over each polygon
QgsFeatureRequest request;
request.setSubsetOfAttributes( QgsAttributeList() );
QgsFeatureIterator fi = vectorProvider->getFeatures( request );
QgsFeature f;
bool statsStoreValues = ( mStatistics & QgsZonalStatistics::Median ) ||
( mStatistics & QgsZonalStatistics::StDev );
bool statsStoreValueCount = ( mStatistics & QgsZonalStatistics::Minority ) ||
( mStatistics & QgsZonalStatistics::Majority );
FeatureStats featureStats( statsStoreValues, statsStoreValueCount );
int featureCounter = 0;
QgsChangedAttributesMap changeMap;
while ( fi.nextFeature( f ) )
{
if ( p )
{
p->setValue( featureCounter );
}
if ( p && p->wasCanceled() )
{
break;
}
if ( !f.constGeometry() )
{
++featureCounter;
continue;
}
const QgsGeometry* featureGeometry = f.constGeometry();
QgsRectangle featureRect = featureGeometry->boundingBox().intersect( &rasterBBox );
if ( featureRect.isEmpty() )
{
++featureCounter;
continue;
}
int offsetX, offsetY, nCellsX, nCellsY;
if ( cellInfoForBBox( rasterBBox, featureRect, cellsizeX, cellsizeY, offsetX, offsetY, nCellsX, nCellsY ) != 0 )
{
++featureCounter;
continue;
}
//avoid access to cells outside of the raster (may occur because of rounding)
if (( offsetX + nCellsX ) > nCellsXGDAL )
{
nCellsX = nCellsXGDAL - offsetX;
}
if (( offsetY + nCellsY ) > nCellsYGDAL )
{
nCellsY = nCellsYGDAL - offsetY;
}
statisticsFromMiddlePointTest( rasterBand, featureGeometry, offsetX, offsetY, nCellsX, nCellsY, cellsizeX, cellsizeY,
rasterBBox, featureStats );
if ( featureStats.count <= 1 )
{
//the cell resolution is probably larger than the polygon area. We switch to precise pixel - polygon intersection in this case
statisticsFromPreciseIntersection( rasterBand, featureGeometry, offsetX, offsetY, nCellsX, nCellsY, cellsizeX, cellsizeY,
rasterBBox, featureStats );
}
//write the statistics value to the vector data provider
QgsAttributeMap changeAttributeMap;
if ( mStatistics & QgsZonalStatistics::Count )
changeAttributeMap.insert( countIndex, QVariant( featureStats.count ) );
if ( mStatistics & QgsZonalStatistics::Sum )
changeAttributeMap.insert( sumIndex, QVariant( featureStats.sum ) );
if ( featureStats.count > 0 )
{
double mean = featureStats.sum / featureStats.count;
if ( mStatistics & QgsZonalStatistics::Mean )
changeAttributeMap.insert( meanIndex, QVariant( mean ) );
if ( mStatistics & QgsZonalStatistics::Median )
{
qSort( featureStats.values.begin(), featureStats.values.end() );
int size = featureStats.values.count();
bool even = ( size % 2 ) < 1;
double medianValue;
if ( even )
{
medianValue = ( featureStats.values.at( size / 2 - 1 ) + featureStats.values.at( size / 2 ) ) / 2;
}
else //odd
{
medianValue = featureStats.values.at(( size + 1 ) / 2 - 1 );
}
changeAttributeMap.insert( medianIndex, QVariant( medianValue ) );
}
if ( mStatistics & QgsZonalStatistics::StDev )
{
double sumSquared = 0;
for ( int i = 0; i < featureStats.values.count(); ++i )
{
double diff = featureStats.values.at( i ) - mean;
sumSquared += diff * diff;
}
double stdev = qPow( sumSquared / featureStats.values.count(), 0.5 );
changeAttributeMap.insert( stdevIndex, QVariant( stdev ) );
}
if ( mStatistics & QgsZonalStatistics::Min )
changeAttributeMap.insert( minIndex, QVariant( featureStats.min ) );
if ( mStatistics & QgsZonalStatistics::Max )
changeAttributeMap.insert( maxIndex, QVariant( featureStats.max ) );
if ( mStatistics & QgsZonalStatistics::Range )
changeAttributeMap.insert( rangeIndex, QVariant( featureStats.max - featureStats.min ) );
if ( mStatistics & QgsZonalStatistics::Minority || mStatistics & QgsZonalStatistics::Majority )
{
QList<int> vals = featureStats.valueCount.values();
qSort( vals.begin(), vals.end() );
if ( mStatistics & QgsZonalStatistics::Minority )
{
float minorityKey = featureStats.valueCount.key( vals.first() );
changeAttributeMap.insert( minorityIndex, QVariant( minorityKey ) );
}
if ( mStatistics & QgsZonalStatistics::Majority )
{
float majKey = featureStats.valueCount.key( vals.last() );
changeAttributeMap.insert( majorityIndex, QVariant( majKey ) );
}
}
if ( mStatistics & QgsZonalStatistics::Variety )
changeAttributeMap.insert( varietyIndex, QVariant( featureStats.valueCount.count() ) );
}
changeMap.insert( f.id(), changeAttributeMap );
++featureCounter;
}
vectorProvider->changeAttributeValues( changeMap );
if ( p )
{
p->setValue( featureCount );
}
GDALClose( inputDataset );
mPolygonLayer->updateFields();
if ( p && p->wasCanceled() )
{
return 9;
}
return 0;
}
int QgsZonalStatistics::calculateStatistics( QgsFeedback *feedback )
{
if ( !mPolygonLayer || mPolygonLayer->geometryType() != QgsWkbTypes::PolygonGeometry )
{
return 1;
}
QgsVectorDataProvider *vectorProvider = mPolygonLayer->dataProvider();
if ( !vectorProvider )
{
return 2;
}
if ( !mRasterLayer )
{
return 3;
}
if ( mRasterLayer->bandCount() < mRasterBand )
{
return 4;
}
mRasterProvider = mRasterLayer->dataProvider();
mInputNodataValue = mRasterProvider->sourceNoDataValue( mRasterBand );
//get geometry info about raster layer
int nCellsXProvider = mRasterProvider->xSize();
int nCellsYProvider = mRasterProvider->ySize();
double cellsizeX = mRasterLayer->rasterUnitsPerPixelX();
if ( cellsizeX < 0 )
{
cellsizeX = -cellsizeX;
}
double cellsizeY = mRasterLayer->rasterUnitsPerPixelY();
if ( cellsizeY < 0 )
{
cellsizeY = -cellsizeY;
}
QgsRectangle rasterBBox = mRasterProvider->extent();
//add the new fields to the provider
QList<QgsField> newFieldList;
QString countFieldName;
if ( mStatistics & QgsZonalStatistics::Count )
{
countFieldName = getUniqueFieldName( mAttributePrefix + "count", newFieldList );
QgsField countField( countFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( countField );
}
QString sumFieldName;
if ( mStatistics & QgsZonalStatistics::Sum )
{
sumFieldName = getUniqueFieldName( mAttributePrefix + "sum", newFieldList );
QgsField sumField( sumFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( sumField );
}
QString meanFieldName;
if ( mStatistics & QgsZonalStatistics::Mean )
{
meanFieldName = getUniqueFieldName( mAttributePrefix + "mean", newFieldList );
QgsField meanField( meanFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( meanField );
}
QString medianFieldName;
if ( mStatistics & QgsZonalStatistics::Median )
{
medianFieldName = getUniqueFieldName( mAttributePrefix + "median", newFieldList );
QgsField medianField( medianFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( medianField );
}
QString stdevFieldName;
if ( mStatistics & QgsZonalStatistics::StDev )
{
stdevFieldName = getUniqueFieldName( mAttributePrefix + "stdev", newFieldList );
QgsField stdField( stdevFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( stdField );
}
QString minFieldName;
if ( mStatistics & QgsZonalStatistics::Min )
{
minFieldName = getUniqueFieldName( mAttributePrefix + "min", newFieldList );
QgsField minField( minFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( minField );
}
QString maxFieldName;
if ( mStatistics & QgsZonalStatistics::Max )
{
maxFieldName = getUniqueFieldName( mAttributePrefix + "max", newFieldList );
QgsField maxField( maxFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( maxField );
}
QString rangeFieldName;
if ( mStatistics & QgsZonalStatistics::Range )
{
rangeFieldName = getUniqueFieldName( mAttributePrefix + "range", newFieldList );
QgsField rangeField( rangeFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( rangeField );
}
QString minorityFieldName;
if ( mStatistics & QgsZonalStatistics::Minority )
{
minorityFieldName = getUniqueFieldName( mAttributePrefix + "minority", newFieldList );
QgsField minorityField( minorityFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( minorityField );
}
QString majorityFieldName;
if ( mStatistics & QgsZonalStatistics::Majority )
{
majorityFieldName = getUniqueFieldName( mAttributePrefix + "majority", newFieldList );
QgsField majField( majorityFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( majField );
}
QString varietyFieldName;
if ( mStatistics & QgsZonalStatistics::Variety )
{
varietyFieldName = getUniqueFieldName( mAttributePrefix + "variety", newFieldList );
QgsField varietyField( varietyFieldName, QVariant::Int, QStringLiteral( "int" ) );
newFieldList.push_back( varietyField );
}
QString varianceFieldName;
if ( mStatistics & QgsZonalStatistics::Variance )
{
varianceFieldName = getUniqueFieldName( mAttributePrefix + "variance", newFieldList );
QgsField varianceField( varianceFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
newFieldList.push_back( varianceField );
}
vectorProvider->addAttributes( newFieldList );
//index of the new fields
int countIndex = mStatistics & QgsZonalStatistics::Count ? vectorProvider->fieldNameIndex( countFieldName ) : -1;
int sumIndex = mStatistics & QgsZonalStatistics::Sum ? vectorProvider->fieldNameIndex( sumFieldName ) : -1;
int meanIndex = mStatistics & QgsZonalStatistics::Mean ? vectorProvider->fieldNameIndex( meanFieldName ) : -1;
int medianIndex = mStatistics & QgsZonalStatistics::Median ? vectorProvider->fieldNameIndex( medianFieldName ) : -1;
int stdevIndex = mStatistics & QgsZonalStatistics::StDev ? vectorProvider->fieldNameIndex( stdevFieldName ) : -1;
int minIndex = mStatistics & QgsZonalStatistics::Min ? vectorProvider->fieldNameIndex( minFieldName ) : -1;
int maxIndex = mStatistics & QgsZonalStatistics::Max ? vectorProvider->fieldNameIndex( maxFieldName ) : -1;
int rangeIndex = mStatistics & QgsZonalStatistics::Range ? vectorProvider->fieldNameIndex( rangeFieldName ) : -1;
int minorityIndex = mStatistics & QgsZonalStatistics::Minority ? vectorProvider->fieldNameIndex( minorityFieldName ) : -1;
int majorityIndex = mStatistics & QgsZonalStatistics::Majority ? vectorProvider->fieldNameIndex( majorityFieldName ) : -1;
int varietyIndex = mStatistics & QgsZonalStatistics::Variety ? vectorProvider->fieldNameIndex( varietyFieldName ) : -1;
int varianceIndex = mStatistics & QgsZonalStatistics::Variance ? vectorProvider->fieldNameIndex( varianceFieldName ) : -1;
if ( ( mStatistics & QgsZonalStatistics::Count && countIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Sum && sumIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Mean && meanIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Median && medianIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::StDev && stdevIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Min && minIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Max && maxIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Range && rangeIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Minority && minorityIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Majority && majorityIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Variety && varietyIndex == -1 )
|| ( mStatistics & QgsZonalStatistics::Variance && varianceIndex == -1 )
)
{
//failed to create a required field
return 8;
}
//progress dialog
long featureCount = vectorProvider->featureCount();
//iterate over each polygon
QgsFeatureRequest request;
request.setSubsetOfAttributes( QgsAttributeList() );
QgsFeatureIterator fi = vectorProvider->getFeatures( request );
QgsFeature f;
bool statsStoreValues = ( mStatistics & QgsZonalStatistics::Median ) ||
( mStatistics & QgsZonalStatistics::StDev ) ||
( mStatistics & QgsZonalStatistics::Variance );
bool statsStoreValueCount = ( mStatistics & QgsZonalStatistics::Minority ) ||
( mStatistics & QgsZonalStatistics::Majority );
FeatureStats featureStats( statsStoreValues, statsStoreValueCount );
int featureCounter = 0;
QgsChangedAttributesMap changeMap;
while ( fi.nextFeature( f ) )
{
if ( feedback && feedback->isCanceled() )
{
break;
}
if ( feedback )
{
feedback->setProgress( 100.0 * static_cast< double >( featureCounter ) / featureCount );
}
if ( !f.hasGeometry() )
{
++featureCounter;
continue;
}
QgsGeometry featureGeometry = f.geometry();
QgsRectangle featureRect = featureGeometry.boundingBox().intersect( &rasterBBox );
if ( featureRect.isEmpty() )
{
++featureCounter;
continue;
}
int offsetX, offsetY, nCellsX, nCellsY;
if ( cellInfoForBBox( rasterBBox, featureRect, cellsizeX, cellsizeY, offsetX, offsetY, nCellsX, nCellsY ) != 0 )
{
++featureCounter;
continue;
}
//avoid access to cells outside of the raster (may occur because of rounding)
if ( ( offsetX + nCellsX ) > nCellsXProvider )
{
nCellsX = nCellsXProvider - offsetX;
}
if ( ( offsetY + nCellsY ) > nCellsYProvider )
{
nCellsY = nCellsYProvider - offsetY;
}
statisticsFromMiddlePointTest( featureGeometry, offsetX, offsetY, nCellsX, nCellsY, cellsizeX, cellsizeY,
rasterBBox, featureStats );
if ( featureStats.count <= 1 )
{
//the cell resolution is probably larger than the polygon area. We switch to precise pixel - polygon intersection in this case
statisticsFromPreciseIntersection( featureGeometry, offsetX, offsetY, nCellsX, nCellsY, cellsizeX, cellsizeY,
rasterBBox, featureStats );
}
//write the statistics value to the vector data provider
QgsAttributeMap changeAttributeMap;
if ( mStatistics & QgsZonalStatistics::Count )
changeAttributeMap.insert( countIndex, QVariant( featureStats.count ) );
if ( mStatistics & QgsZonalStatistics::Sum )
changeAttributeMap.insert( sumIndex, QVariant( featureStats.sum ) );
if ( featureStats.count > 0 )
{
double mean = featureStats.sum / featureStats.count;
if ( mStatistics & QgsZonalStatistics::Mean )
changeAttributeMap.insert( meanIndex, QVariant( mean ) );
if ( mStatistics & QgsZonalStatistics::Median )
{
std::sort( featureStats.values.begin(), featureStats.values.end() );
int size = featureStats.values.count();
bool even = ( size % 2 ) < 1;
double medianValue;
if ( even )
{
medianValue = ( featureStats.values.at( size / 2 - 1 ) + featureStats.values.at( size / 2 ) ) / 2;
}
else //odd
{
medianValue = featureStats.values.at( ( size + 1 ) / 2 - 1 );
}
changeAttributeMap.insert( medianIndex, QVariant( medianValue ) );
}
if ( mStatistics & QgsZonalStatistics::StDev || mStatistics & QgsZonalStatistics::Variance )
{
double sumSquared = 0;
for ( int i = 0; i < featureStats.values.count(); ++i )
{
double diff = featureStats.values.at( i ) - mean;
sumSquared += diff * diff;
}
double variance = sumSquared / featureStats.values.count();
if ( mStatistics & QgsZonalStatistics::StDev )
{
double stdev = std::pow( variance, 0.5 );
changeAttributeMap.insert( stdevIndex, QVariant( stdev ) );
}
if ( mStatistics & QgsZonalStatistics::Variance )
changeAttributeMap.insert( varianceIndex, QVariant( variance ) );
}
if ( mStatistics & QgsZonalStatistics::Min )
changeAttributeMap.insert( minIndex, QVariant( featureStats.min ) );
if ( mStatistics & QgsZonalStatistics::Max )
changeAttributeMap.insert( maxIndex, QVariant( featureStats.max ) );
if ( mStatistics & QgsZonalStatistics::Range )
changeAttributeMap.insert( rangeIndex, QVariant( featureStats.max - featureStats.min ) );
if ( mStatistics & QgsZonalStatistics::Minority || mStatistics & QgsZonalStatistics::Majority )
{
QList<int> vals = featureStats.valueCount.values();
std::sort( vals.begin(), vals.end() );
if ( mStatistics & QgsZonalStatistics::Minority )
{
float minorityKey = featureStats.valueCount.key( vals.first() );
changeAttributeMap.insert( minorityIndex, QVariant( minorityKey ) );
}
if ( mStatistics & QgsZonalStatistics::Majority )
{
float majKey = featureStats.valueCount.key( vals.last() );
changeAttributeMap.insert( majorityIndex, QVariant( majKey ) );
}
}
if ( mStatistics & QgsZonalStatistics::Variety )
changeAttributeMap.insert( varietyIndex, QVariant( featureStats.valueCount.count() ) );
}
changeMap.insert( f.id(), changeAttributeMap );
++featureCounter;
}
vectorProvider->changeAttributeValues( changeMap );
if ( feedback )
{
feedback->setProgress( 100 );
}
mPolygonLayer->updateFields();
if ( feedback && feedback->isCanceled() )
{
return 9;
}
return 0;
}
int QgsZonalStatistics::calculateStatistics( QProgressDialog* p )
{
if ( !mPolygonLayer || mPolygonLayer->geometryType() != QGis::Polygon )
{
return 1;
}
QgsVectorDataProvider* vectorProvider = mPolygonLayer->dataProvider();
if ( !vectorProvider )
{
return 2;
}
//open the raster layer and the raster band
GDALAllRegister();
GDALDatasetH inputDataset = GDALOpen( TO8F( mRasterFilePath ), GA_ReadOnly );
if ( inputDataset == NULL )
{
return 3;
}
if ( GDALGetRasterCount( inputDataset ) < ( mRasterBand - 1 ) )
{
GDALClose( inputDataset );
return 4;
}
GDALRasterBandH rasterBand = GDALGetRasterBand( inputDataset, mRasterBand );
if ( rasterBand == NULL )
{
GDALClose( inputDataset );
return 5;
}
mInputNodataValue = GDALGetRasterNoDataValue( rasterBand, NULL );
//get geometry info about raster layer
int nCellsXGDAL = GDALGetRasterXSize( inputDataset );
int nCellsYGDAL = GDALGetRasterYSize( inputDataset );
double geoTransform[6];
if ( GDALGetGeoTransform( inputDataset, geoTransform ) != CE_None )
{
GDALClose( inputDataset );
return 6;
}
double cellsizeX = geoTransform[1];
if ( cellsizeX < 0 )
{
cellsizeX = -cellsizeX;
}
double cellsizeY = geoTransform[5];
if ( cellsizeY < 0 )
{
cellsizeY = -cellsizeY;
}
QgsRectangle rasterBBox( geoTransform[0], geoTransform[3] - ( nCellsYGDAL * cellsizeY ),
geoTransform[0] + ( nCellsXGDAL * cellsizeX ), geoTransform[3] );
//add the new count, sum, mean fields to the provider
QList<QgsField> newFieldList;
QString countFieldName = getUniqueFieldName( mAttributePrefix + "count" );
QString sumFieldName = getUniqueFieldName( mAttributePrefix + "sum" );
QString meanFieldName = getUniqueFieldName( mAttributePrefix + "mean" );
QgsField countField( countFieldName, QVariant::Double, "double precision" );
QgsField sumField( sumFieldName, QVariant::Double, "double precision" );
QgsField meanField( meanFieldName, QVariant::Double, "double precision" );
newFieldList.push_back( countField );
newFieldList.push_back( sumField );
newFieldList.push_back( meanField );
vectorProvider->addAttributes( newFieldList );
//index of the new fields
int countIndex = vectorProvider->fieldNameIndex( countFieldName );
int sumIndex = vectorProvider->fieldNameIndex( sumFieldName );
int meanIndex = vectorProvider->fieldNameIndex( meanFieldName );
if ( countIndex == -1 || sumIndex == -1 || meanIndex == -1 )
{
return 8;
}
//progress dialog
long featureCount = vectorProvider->featureCount();
if ( p )
{
p->setMaximum( featureCount );
}
//iterate over each polygon
QgsFeatureRequest request;
request.setSubsetOfAttributes( QgsAttributeList() );
QgsFeatureIterator fi = vectorProvider->getFeatures( request );
QgsFeature f;
double count = 0;
double sum = 0;
double mean = 0;
int featureCounter = 0;
while ( fi.nextFeature( f ) )
{
if ( p )
{
p->setValue( featureCounter );
}
if ( p && p->wasCanceled() )
{
break;
}
QgsGeometry* featureGeometry = f.geometry();
if ( !featureGeometry )
{
++featureCounter;
continue;
}
QgsRectangle featureRect = featureGeometry->boundingBox().intersect( &rasterBBox );
if ( featureRect.isEmpty() )
{
++featureCounter;
continue;
}
int offsetX, offsetY, nCellsX, nCellsY;
if ( cellInfoForBBox( rasterBBox, featureRect, cellsizeX, cellsizeY, offsetX, offsetY, nCellsX, nCellsY ) != 0 )
{
++featureCounter;
continue;
}
//avoid access to cells outside of the raster (may occur because of rounding)
if (( offsetX + nCellsX ) > nCellsXGDAL )
{
nCellsX = nCellsXGDAL - offsetX;
}
if (( offsetY + nCellsY ) > nCellsYGDAL )
{
nCellsY = nCellsYGDAL - offsetY;
}
statisticsFromMiddlePointTest( rasterBand, featureGeometry, offsetX, offsetY, nCellsX, nCellsY, cellsizeX, cellsizeY,
rasterBBox, sum, count );
if ( count <= 1 )
{
//the cell resolution is probably larger than the polygon area. We switch to precise pixel - polygon intersection in this case
statisticsFromPreciseIntersection( rasterBand, featureGeometry, offsetX, offsetY, nCellsX, nCellsY, cellsizeX, cellsizeY,
rasterBBox, sum, count );
}
if ( count == 0 )
{
mean = 0;
}
else
{
mean = sum / count;
}
//write the statistics value to the vector data provider
QgsChangedAttributesMap changeMap;
QgsAttributeMap changeAttributeMap;
changeAttributeMap.insert( countIndex, QVariant( count ) );
changeAttributeMap.insert( sumIndex, QVariant( sum ) );
changeAttributeMap.insert( meanIndex, QVariant( mean ) );
changeMap.insert( f.id(), changeAttributeMap );
vectorProvider->changeAttributeValues( changeMap );
++featureCounter;
}
if ( p )
{
p->setValue( featureCount );
}
GDALClose( inputDataset );
mPolygonLayer->updateFields();
if ( p && p->wasCanceled() )
{
return 9;
}
return 0;
}