QGIS API Documentation 3.38.0-Grenoble (exported)
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qgsalgorithmroundrastervalues.cpp
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1/***************************************************************************
2 qgsalgorithmroundrastervalues.cpp
3 ---------------------
4 begin : April 2020
5 copyright : (C) 2020 by Clemens Raffler
6 email : clemens dot raffler at gmail dot com
7 ***************************************************************************/
8
9/***************************************************************************
10 * *
11 * This program is free software; you can redistribute it and/or modify *
12 * it under the terms of the GNU General Public License as published by *
13 * the Free Software Foundation; either version 2 of the License, or *
14 * (at your option) any later version. *
15 * *
16 ***************************************************************************/
17
19#include "qgsrasterfilewriter.h"
20
22
23QString QgsRoundRasterValuesAlgorithm::name() const
24{
25 return QStringLiteral( "roundrastervalues" );
26}
27
28QString QgsRoundRasterValuesAlgorithm::displayName() const
29{
30 return QObject::tr( "Round raster" );
31}
32
33QStringList QgsRoundRasterValuesAlgorithm::tags() const
34{
35 return QObject::tr( "data,cells,round,truncate" ).split( ',' );
36}
37
38QString QgsRoundRasterValuesAlgorithm::group() const
39{
40 return QObject::tr( "Raster analysis" );
41}
42
43QString QgsRoundRasterValuesAlgorithm::groupId() const
44{
45 return QStringLiteral( "rasteranalysis" );
46}
47
48void QgsRoundRasterValuesAlgorithm::initAlgorithm( const QVariantMap & )
49{
50 addParameter( new QgsProcessingParameterRasterLayer( QStringLiteral( "INPUT" ), QStringLiteral( "Input raster" ) ) );
51 addParameter( new QgsProcessingParameterBand( QStringLiteral( "BAND" ), QObject::tr( "Band number" ), 1, QStringLiteral( "INPUT" ) ) );
52 addParameter( new QgsProcessingParameterEnum( QStringLiteral( "ROUNDING_DIRECTION" ), QObject::tr( "Rounding direction" ), QStringList() << QObject::tr( "Round up" ) << QObject::tr( "Round to nearest" ) << QObject::tr( "Round down" ), false, 1 ) );
53 addParameter( new QgsProcessingParameterNumber( QStringLiteral( "DECIMAL_PLACES" ), QObject::tr( "Number of decimals places" ), Qgis::ProcessingNumberParameterType::Integer, 2 ) );
54 addParameter( new QgsProcessingParameterRasterDestination( QStringLiteral( "OUTPUT" ), QObject::tr( "Output raster" ) ) );
55 std::unique_ptr< QgsProcessingParameterDefinition > baseParameter = std::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "BASE_N" ), QObject::tr( "Base n for rounding to multiples of n" ), Qgis::ProcessingNumberParameterType::Integer, 10, true, 1 );
56 baseParameter->setFlags( Qgis::ProcessingParameterFlag::Advanced );
57 addParameter( baseParameter.release() );
58}
59
60QString QgsRoundRasterValuesAlgorithm::shortHelpString() const
61{
62 return QObject::tr( "This algorithm rounds the cell values of a raster dataset according to the specified number of decimals.\n "
63 "Alternatively, a negative number of decimal places may be used to round values to powers of a base n "
64 "(specified in the advanced parameter Base n). For example, with a Base value n of 10 and Decimal places of -1 "
65 "the algorithm rounds cell values to multiples of 10, -2 rounds to multiples of 100, and so on. Arbitrary base values "
66 "may be chosen, the algorithm applies the same multiplicative principle. Rounding cell values to multiples of "
67 "a base n may be used to generalize raster layers.\n"
68 "The algorithm preserves the data type of the input raster. Therefore byte/integer rasters can only be rounded "
69 "to multiples of a base n, otherwise a warning is raised and the raster gets copied as byte/integer raster" );
70}
71
72QgsRoundRasterValuesAlgorithm *QgsRoundRasterValuesAlgorithm::createInstance() const
73{
74 return new QgsRoundRasterValuesAlgorithm();
75}
76
77bool QgsRoundRasterValuesAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
78{
79 Q_UNUSED( feedback );
80 QgsRasterLayer *inputRaster = parameterAsRasterLayer( parameters, QStringLiteral( "INPUT" ), context );
81 mDecimalPrecision = parameterAsInt( parameters, QStringLiteral( "DECIMAL_PLACES" ), context );
82 mBaseN = parameterAsInt( parameters, QStringLiteral( "BASE_N" ), context );
83 mMultipleOfBaseN = pow( mBaseN, abs( mDecimalPrecision ) );
84 mScaleFactor = std::pow( 10.0, mDecimalPrecision );
85
86 if ( !inputRaster )
87 throw QgsProcessingException( invalidRasterError( parameters, QStringLiteral( "INPUT" ) ) );
88
89 mBand = parameterAsInt( parameters, QStringLiteral( "BAND" ), context );
90 if ( mBand < 1 || mBand > inputRaster->bandCount() )
91 throw QgsProcessingException( QObject::tr( "Invalid band number for BAND (%1): Valid values for input raster are 1 to %2" ).arg( mBand ).arg( inputRaster->bandCount() ) );
92
93 mRoundingDirection = parameterAsEnum( parameters, QStringLiteral( "ROUNDING_DIRECTION" ), context );
94
95 mInterface.reset( inputRaster->dataProvider()->clone() );
96 mDataType = mInterface->dataType( mBand );
97
98 switch ( mDataType )
99 {
105 mIsInteger = true;
106 if ( mDecimalPrecision > -1 )
107 feedback->reportError( QObject::tr( "Input raster is of byte or integer type. The cell values cannot be rounded and will be output using the same data type." ), false );
108 break;
109 default:
110 mIsInteger = false;
111 break;
112 }
113
114 mInputNoDataValue = inputRaster->dataProvider()->sourceNoDataValue( mBand );
115 mExtent = inputRaster->extent();
116 mLayerWidth = inputRaster->width();
117 mLayerHeight = inputRaster->height();
118 mCrs = inputRaster->crs();
119 mNbCellsXProvider = mInterface->xSize();
120 mNbCellsYProvider = mInterface->ySize();
121 return true;
122}
123
124QVariantMap QgsRoundRasterValuesAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
125{
126 //prepare output dataset
127 const QString outputFile = parameterAsOutputLayer( parameters, QStringLiteral( "OUTPUT" ), context );
128 const QFileInfo fi( outputFile );
129 const QString outputFormat = QgsRasterFileWriter::driverForExtension( fi.suffix() );
130 std::unique_ptr< QgsRasterFileWriter > writer = std::make_unique< QgsRasterFileWriter >( outputFile );
131 writer->setOutputProviderKey( QStringLiteral( "gdal" ) );
132 writer->setOutputFormat( outputFormat );
133 std::unique_ptr<QgsRasterDataProvider > provider( writer->createOneBandRaster( mInterface->dataType( mBand ), mNbCellsXProvider, mNbCellsYProvider, mExtent, mCrs ) );
134 if ( !provider )
135 throw QgsProcessingException( QObject::tr( "Could not create raster output: %1" ).arg( outputFile ) );
136 if ( !provider->isValid() )
137 throw QgsProcessingException( QObject::tr( "Could not create raster output %1: %2" ).arg( outputFile, provider->error().message( QgsErrorMessage::Text ) ) );
138
139 //prepare output provider
140 QgsRasterDataProvider *destinationRasterProvider;
141 destinationRasterProvider = provider.get();
142 destinationRasterProvider->setEditable( true );
143 destinationRasterProvider->setNoDataValue( 1, mInputNoDataValue );
144
147 const int nbBlocksWidth = static_cast< int >( std::ceil( 1.0 * mLayerWidth / maxWidth ) );
148 const int nbBlocksHeight = static_cast< int >( std::ceil( 1.0 * mLayerHeight / maxHeight ) );
149 const int nbBlocks = nbBlocksWidth * nbBlocksHeight;
150
151 QgsRasterIterator iter( mInterface.get() );
152 iter.startRasterRead( mBand, mLayerWidth, mLayerHeight, mExtent );
153 int iterLeft = 0;
154 int iterTop = 0;
155 int iterCols = 0;
156 int iterRows = 0;
157 std::unique_ptr< QgsRasterBlock > analysisRasterBlock;
158 while ( iter.readNextRasterPart( mBand, iterCols, iterRows, analysisRasterBlock, iterLeft, iterTop ) )
159 {
160 if ( feedback )
161 feedback->setProgress( 100 * ( ( iterTop / maxHeight * nbBlocksWidth ) + iterLeft / maxWidth ) / nbBlocks );
162 if ( mIsInteger && mDecimalPrecision > -1 )
163 {
164 //nothing to round, just write raster block
165 analysisRasterBlock->setNoDataValue( mInputNoDataValue );
166 destinationRasterProvider->writeBlock( analysisRasterBlock.get(), mBand, iterLeft, iterTop );
167 }
168 else
169 {
170 for ( int row = 0; row < iterRows; row++ )
171 {
172 if ( feedback && feedback->isCanceled() )
173 break;
174 for ( int column = 0; column < iterCols; column++ )
175 {
176 bool isNoData = false;
177 const double val = analysisRasterBlock->valueAndNoData( row, column, isNoData );
178 if ( isNoData )
179 {
180 analysisRasterBlock->setValue( row, column, mInputNoDataValue );
181 }
182 else
183 {
184 double roundedVal = mInputNoDataValue;
185 if ( mRoundingDirection == 0 && mDecimalPrecision < 0 )
186 {
187 roundedVal = roundUpBaseN( val );
188 }
189 else if ( mRoundingDirection == 0 && mDecimalPrecision > -1 )
190 {
191 const double m = ( val < 0.0 ) ? -1.0 : 1.0;
192 roundedVal = roundUp( val, m );
193 }
194 else if ( mRoundingDirection == 1 && mDecimalPrecision < 0 )
195 {
196 roundedVal = roundNearestBaseN( val );
197 }
198 else if ( mRoundingDirection == 1 && mDecimalPrecision > -1 )
199 {
200 const double m = ( val < 0.0 ) ? -1.0 : 1.0;
201 roundedVal = roundNearest( val, m );
202 }
203 else if ( mRoundingDirection == 2 && mDecimalPrecision < 0 )
204 {
205 roundedVal = roundDownBaseN( val );
206 }
207 else
208 {
209 const double m = ( val < 0.0 ) ? -1.0 : 1.0;
210 roundedVal = roundDown( val, m );
211 }
212 //integer values get automatically cast to double when reading and back to int when writing
213 analysisRasterBlock->setValue( row, column, roundedVal );
214 }
215 }
216 }
217 destinationRasterProvider->writeBlock( analysisRasterBlock.get(), mBand, iterLeft, iterTop );
218 }
219 }
220 destinationRasterProvider->setEditable( false );
221
222 QVariantMap outputs;
223 outputs.insert( QStringLiteral( "OUTPUT" ), outputFile );
224 return outputs;
225}
226
227double QgsRoundRasterValuesAlgorithm::roundNearest( double value, double m )
228{
229 return ( std::round( value * m * mScaleFactor ) / mScaleFactor ) * m;
230}
231
232double QgsRoundRasterValuesAlgorithm::roundUp( double value, double m )
233{
234 return ( std::ceil( value * m * mScaleFactor ) / mScaleFactor ) * m;
235}
236
237double QgsRoundRasterValuesAlgorithm::roundDown( double value, double m )
238{
239 return ( std::floor( value * m * mScaleFactor ) / mScaleFactor ) * m;
240}
241
242
243double QgsRoundRasterValuesAlgorithm::roundNearestBaseN( double value )
244{
245 return static_cast<double>( mMultipleOfBaseN * round( value / mMultipleOfBaseN ) );
246}
247
248double QgsRoundRasterValuesAlgorithm::roundUpBaseN( double value )
249{
250 return static_cast<double>( mMultipleOfBaseN * ceil( value / mMultipleOfBaseN ) );
251}
252
253double QgsRoundRasterValuesAlgorithm::roundDownBaseN( double value )
254{
255 return static_cast<double>( mMultipleOfBaseN * floor( value / mMultipleOfBaseN ) );
256}
257
258
259
260
@ Int16
Sixteen bit signed integer (qint16)
@ UInt16
Sixteen bit unsigned integer (quint16)
@ Byte
Eight bit unsigned integer (quint8)
@ Int32
Thirty two bit signed integer (qint32)
@ UInt32
Thirty two bit unsigned integer (quint32)
@ Advanced
Parameter is an advanced parameter which should be hidden from users by default.
bool isCanceled() const
Tells whether the operation has been canceled already.
Definition qgsfeedback.h:53
void setProgress(double progress)
Sets the current progress for the feedback object.
Definition qgsfeedback.h:61
virtual QgsRectangle extent() const
Returns the extent of the layer.
QgsCoordinateReferenceSystem crs
Definition qgsmaplayer.h:82
Contains information about the context in which a processing algorithm is executed.
Custom exception class for processing related exceptions.
Base class for providing feedback from a processing algorithm.
virtual void reportError(const QString &error, bool fatalError=false)
Reports that the algorithm encountered an error while executing.
A raster band parameter for Processing algorithms.
An enum based parameter for processing algorithms, allowing for selection from predefined values.
A numeric parameter for processing algorithms.
A raster layer destination parameter, for specifying the destination path for a raster layer created ...
A raster layer parameter for processing algorithms.
Base class for raster data providers.
QgsRasterDataProvider * clone() const override=0
Clone itself, create deep copy.
virtual bool setNoDataValue(int bandNo, double noDataValue)
Set no data value on created dataset.
virtual double sourceNoDataValue(int bandNo) const
Value representing no data value.
bool writeBlock(QgsRasterBlock *block, int band, int xOffset=0, int yOffset=0)
Writes pixel data from a raster block into the provider data source.
virtual bool setEditable(bool enabled)
Turns on/off editing mode of the provider.
static QString driverForExtension(const QString &extension)
Returns the GDAL driver name for a specified file extension.
Iterator for sequentially processing raster cells.
static const int DEFAULT_MAXIMUM_TILE_WIDTH
Default maximum tile width.
static const int DEFAULT_MAXIMUM_TILE_HEIGHT
Default maximum tile height.
Represents a raster layer.
int height() const
Returns the height of the (unclipped) raster.
int bandCount() const
Returns the number of bands in this layer.
QgsRasterDataProvider * dataProvider() override
Returns the source data provider.
int width() const
Returns the width of the (unclipped) raster.