QGIS API Documentation 3.39.0-Master (67e056379ed)
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qgsalgorithmconstantraster.cpp
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1/***************************************************************************
2 qgsalgorithmconstantraster.cpp
3 ---------------------
4 begin : November 2019
5 copyright : (C) 2019 by Alexander Bruy
6 email : alexander dot bruy 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
18#include <limits>
19#include "math.h"
21#include "qgsrasterfilewriter.h"
22
24
25QString QgsConstantRasterAlgorithm::name() const
26{
27 return QStringLiteral( "createconstantrasterlayer" );
28}
29
30QString QgsConstantRasterAlgorithm::displayName() const
31{
32 return QObject::tr( "Create constant raster layer" );
33}
34
35QStringList QgsConstantRasterAlgorithm::tags() const
36{
37 return QObject::tr( "raster,create,constant" ).split( ',' );
38}
39
40QString QgsConstantRasterAlgorithm::group() const
41{
42 return QObject::tr( "Raster creation" );
43}
44
45QString QgsConstantRasterAlgorithm::groupId() const
46{
47 return QStringLiteral( "rastercreation" );
48}
49
50QString QgsConstantRasterAlgorithm::shortHelpString() const
51{
52 return QObject::tr( "Generates raster layer for given extent and cell "
53 "size filled with the specified value.\n"
54 "Additionally an output data type can be specified. "
55 "The algorithm will abort if a value has been entered that "
56 "cannot be represented by the selected output raster data type." );
57}
58
59QgsConstantRasterAlgorithm *QgsConstantRasterAlgorithm::createInstance() const
60{
61 return new QgsConstantRasterAlgorithm();
62}
63
64void QgsConstantRasterAlgorithm::initAlgorithm( const QVariantMap & )
65{
66 addParameter( new QgsProcessingParameterExtent( QStringLiteral( "EXTENT" ), QObject::tr( "Desired extent" ) ) );
67 addParameter( new QgsProcessingParameterCrs( QStringLiteral( "TARGET_CRS" ), QObject::tr( "Target CRS" ), QStringLiteral( "ProjectCrs" ) ) );
68 addParameter( new QgsProcessingParameterNumber( QStringLiteral( "PIXEL_SIZE" ), QObject::tr( "Pixel size" ),
70 addParameter( new QgsProcessingParameterNumber( QStringLiteral( "NUMBER" ), QObject::tr( "Constant value" ),
72
73 QStringList rasterDataTypes; //currently supported raster data types that can be handled QgsRasterBlock::writeValue()
74 rasterDataTypes << QStringLiteral( "Byte" )
75 << QStringLiteral( "Integer16" )
76 << QStringLiteral( "Unsigned Integer16" )
77 << QStringLiteral( "Integer32" )
78 << QStringLiteral( "Unsigned Integer32" )
79 << QStringLiteral( "Float32" )
80 << QStringLiteral( "Float64" );
81
82 //QGIS3: parameter set to Float32 by default so that existing models/scripts don't break
83 std::unique_ptr< QgsProcessingParameterDefinition > rasterTypeParameter = std::make_unique< QgsProcessingParameterEnum >( QStringLiteral( "OUTPUT_TYPE" ), QObject::tr( "Output raster data type" ), rasterDataTypes, false, 5, false );
84 rasterTypeParameter->setFlags( Qgis::ProcessingParameterFlag::Advanced );
85 addParameter( rasterTypeParameter.release() );
86
87 std::unique_ptr< QgsProcessingParameterString > createOptsParam = std::make_unique< QgsProcessingParameterString >( QStringLiteral( "CREATE_OPTIONS" ), QObject::tr( "Creation options" ), QVariant(), false, true );
88 createOptsParam->setMetadata( QVariantMap( {{QStringLiteral( "widget_wrapper" ), QVariantMap( {{QStringLiteral( "widget_type" ), QStringLiteral( "rasteroptions" ) }} ) }} ) );
89 createOptsParam->setFlags( createOptsParam->flags() | Qgis::ProcessingParameterFlag::Advanced );
90 addParameter( createOptsParam.release() );
91
92 addParameter( new QgsProcessingParameterRasterDestination( QStringLiteral( "OUTPUT" ), QObject::tr( "Constant" ) ) );
93}
94
95QVariantMap QgsConstantRasterAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
96{
97 const QgsCoordinateReferenceSystem crs = parameterAsCrs( parameters, QStringLiteral( "TARGET_CRS" ), context );
98 const QgsRectangle extent = parameterAsExtent( parameters, QStringLiteral( "EXTENT" ), context, crs );
99 const double pixelSize = parameterAsDouble( parameters, QStringLiteral( "PIXEL_SIZE" ), context );
100 const double value = parameterAsDouble( parameters, QStringLiteral( "NUMBER" ), context );
101 const int typeId = parameterAsInt( parameters, QStringLiteral( "OUTPUT_TYPE" ), context );
102
103 if ( pixelSize <= 0 )
104 {
105 throw QgsProcessingException( QObject::tr( "Pixel size must be greater than 0." ) );
106 }
107
108 //implement warning if input float has decimal places but is written to integer raster
109 double fractpart;
110 double intpart;
111 fractpart = abs( std::modf( value, &intpart ) ); //@abs: negative values may be entered
112
113 Qgis::DataType rasterDataType = Qgis::DataType::Float32; //standard output type
114 switch ( typeId )
115 {
116 case 0:
117 rasterDataType = Qgis::DataType::Byte;
118 if ( value < std::numeric_limits<quint8>::min() || value > std::numeric_limits<quint8>::max() )
119 throw QgsProcessingException( QObject::tr( "Raster datasets of type %3 only accept positive values between %1 and %2" ).arg( std::numeric_limits<quint8>::min() ).arg( std::numeric_limits<quint8>::max() ).arg( QLatin1String( "Byte" ) ) );
120 if ( fractpart > 0 )
121 feedback->reportError( QObject::tr( "The entered constant value has decimals but will be written to a raster dataset of type %1. The decimals of the constant value will be omitted." ).arg( QLatin1String( "Byte" ) ) );
122 break;
123 case 1:
124 rasterDataType = Qgis::DataType::Int16;
125 if ( value < std::numeric_limits<qint16>::min() || value > std::numeric_limits<qint16>::max() )
126 throw QgsProcessingException( QObject::tr( "Raster datasets of type %3 only accept values between %1 and %2" ).arg( std::numeric_limits<qint16>::min() ).arg( std::numeric_limits<qint16>::max() ).arg( QLatin1String( "Integer16" ) ) );
127 if ( fractpart > 0 )
128 feedback->reportError( QObject::tr( "The entered constant value has decimals but will be written to a raster dataset of type %1. The decimals of the constant value will be omitted." ).arg( QLatin1String( "Integer16" ) ) );
129 break;
130 case 2:
131 rasterDataType = Qgis::DataType::UInt16;
132 if ( value < std::numeric_limits<quint16>::min() || value > std::numeric_limits<quint16>::max() )
133 throw QgsProcessingException( QObject::tr( "Raster datasets of type %3 only accept positive values between %1 and %2" ).arg( std::numeric_limits<quint16>::min() ).arg( std::numeric_limits<quint16>::max() ).arg( "Unsigned Integer16" ) );
134 if ( fractpart > 0 )
135 feedback->reportError( QObject::tr( "The entered constant value has decimals but will be written to a raster dataset of type %1. The decimals of the constant value will be omitted." ).arg( QLatin1String( "Unsigned Integer16" ) ) );
136 break;
137 case 3:
138 rasterDataType = Qgis::DataType::Int32;
139 if ( value < std::numeric_limits<qint32>::min() || value > std::numeric_limits<qint32>::max() )
140 throw QgsProcessingException( QObject::tr( "Raster datasets of type %3 only accept values between %1 and %2" ).arg( std::numeric_limits<qint32>::min() ).arg( std::numeric_limits<qint32>::max() ).arg( QLatin1String( "Integer32" ) ) );
141 if ( fractpart > 0 )
142 feedback->reportError( QObject::tr( "The entered constant value has decimals but will be written to a raster dataset of type %1. The decimals of the constant value will be omitted." ).arg( QLatin1String( "Integer32" ) ) );
143 break;
144 case 4:
145 rasterDataType = Qgis::DataType::UInt32;
146 if ( value < std::numeric_limits<quint32>::min() || value > std::numeric_limits<quint32>::max() )
147 throw QgsProcessingException( QObject::tr( "Raster datasets of type %3 only accept positive values between %1 and %2" ).arg( std::numeric_limits<quint32>::min() ).arg( std::numeric_limits<quint32>::max() ).arg( QLatin1String( "Unsigned Integer32" ) ) );
148 if ( fractpart > 0 )
149 feedback->reportError( QObject::tr( "The entered constant value has decimals but will be written to a raster dataset of type %1. The decimals of the constant value will be omitted." ).arg( QLatin1String( "Unsigned Integer32" ) ) );
150 break;
151 case 5:
152 rasterDataType = Qgis::DataType::Float32;
153 break;
154 case 6:
155 rasterDataType = Qgis::DataType::Float64;
156 break;
157 default:
158 break;
159 }
160
161 const QString createOptions = parameterAsString( parameters, QStringLiteral( "CREATE_OPTIONS" ), context ).trimmed();
162 const QString outputFile = parameterAsOutputLayer( parameters, QStringLiteral( "OUTPUT" ), context );
163 const QFileInfo fi( outputFile );
164 const QString outputFormat = QgsRasterFileWriter::driverForExtension( fi.suffix() );
165
166 const int rows = std::max( std::ceil( extent.height() / pixelSize ), 1.0 );
167 const int cols = std::max( std::ceil( extent.width() / pixelSize ), 1.0 );
168
169 //build new raster extent based on number of columns and cellsize
170 //this prevents output cellsize being calculated too small
171 const QgsRectangle rasterExtent = QgsRectangle( extent.xMinimum(), extent.yMaximum() - ( rows * pixelSize ), extent.xMinimum() + ( cols * pixelSize ), extent.yMaximum() );
172
173 std::unique_ptr< QgsRasterFileWriter > writer = std::make_unique< QgsRasterFileWriter >( outputFile );
174 writer->setOutputProviderKey( QStringLiteral( "gdal" ) );
175 if ( !createOptions.isEmpty() )
176 {
177 writer->setCreateOptions( createOptions.split( '|' ) );
178 }
179 writer->setOutputFormat( outputFormat );
180 std::unique_ptr<QgsRasterDataProvider > provider( writer->createOneBandRaster( rasterDataType, cols, rows, rasterExtent, crs ) );
181 if ( !provider )
182 throw QgsProcessingException( QObject::tr( "Could not create raster output: %1" ).arg( outputFile ) );
183 if ( !provider->isValid() )
184 throw QgsProcessingException( QObject::tr( "Could not create raster output %1: %2" ).arg( outputFile, provider->error().message( QgsErrorMessage::Text ) ) );
185
186 //Thoughts on noData:
187 //Setting a noData value is disabled so that the user is protected from accidentally creating an empty raster (eg. when value is set to -9999)
188 //We could also allow creating empty rasters by exposing a noData value parameter (usecases?).
189
190 //prepare raw data depending on raster data type
191 QgsRasterBlock block( rasterDataType, cols, 1 );
192 switch ( typeId )
193 {
194 case 0:
195 {
196 std::vector<quint8> byteRow( cols );
197 std::fill( byteRow.begin(), byteRow.end(), value );
198 block.setData( QByteArray::fromRawData( ( char * )&byteRow[0], QgsRasterBlock::typeSize( Qgis::DataType::Byte ) * cols ) );
199 break;
200 }
201 case 1:
202 {
203 std::vector<qint16> int16Row( cols );
204 std::fill( int16Row.begin(), int16Row.end(), value );
205 block.setData( QByteArray::fromRawData( ( char * )&int16Row[0], QgsRasterBlock::typeSize( Qgis::DataType::Int16 ) * cols ) );
206 break;
207 }
208 case 2:
209 {
210 std::vector<quint16> uInt16Row( cols );
211 std::fill( uInt16Row.begin(), uInt16Row.end(), value );
212 block.setData( QByteArray::fromRawData( ( char * )&uInt16Row[0], QgsRasterBlock::typeSize( Qgis::DataType::UInt16 ) * cols ) );
213 break;
214 }
215 case 3:
216 {
217 std::vector<qint32> int32Row( cols );
218 std::fill( int32Row.begin(), int32Row.end(), value );
219 block.setData( QByteArray::fromRawData( ( char * )&int32Row[0], QgsRasterBlock::typeSize( Qgis::DataType::Int32 ) * cols ) );
220 break;
221 }
222 case 4:
223 {
224 std::vector<quint32> uInt32Row( cols );
225 std::fill( uInt32Row.begin(), uInt32Row.end(), value );
226 block.setData( QByteArray::fromRawData( ( char * )&uInt32Row[0], QgsRasterBlock::typeSize( Qgis::DataType::UInt32 ) * cols ) );
227 break;
228 }
229 case 5:
230 {
231 std::vector<float> float32Row( cols );
232 std::fill( float32Row.begin(), float32Row.end(), value );
233 block.setData( QByteArray::fromRawData( ( char * )&float32Row[0], QgsRasterBlock::typeSize( Qgis::DataType::Float32 ) * cols ) );
234 break;
235 }
236 case 6:
237 {
238 std::vector<double> float64Row( cols );
239 std::fill( float64Row.begin(), float64Row.end(), value );
240 block.setData( QByteArray::fromRawData( ( char * )&float64Row[0], QgsRasterBlock::typeSize( Qgis::DataType::Float64 ) * cols ) );
241 break;
242 }
243 default:
244 {
245 std::vector<float> float32Row( cols );
246 std::fill( float32Row.begin(), float32Row.end(), value );
247 block.setData( QByteArray::fromRawData( ( char * )&float32Row[0], QgsRasterBlock::typeSize( Qgis::DataType::Float32 ) * cols ) );
248 break;
249 }
250 }
251
252 const double step = rows > 0 ? 100.0 / rows : 1;
253
254 for ( int i = 0; i < rows ; i++ )
255 {
256 if ( feedback->isCanceled() )
257 {
258 break;
259 }
260
261 provider->writeBlock( &block, 1, 0, i );
262 feedback->setProgress( i * step );
263 }
264
265 QVariantMap outputs;
266 outputs.insert( QStringLiteral( "OUTPUT" ), outputFile );
267 return outputs;
268}
269
DataType
Raster data types.
Definition qgis.h:288
@ Float32
Thirty two bit floating point (float)
@ 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)
@ Float64
Sixty four bit floating point (double)
@ UInt32
Thirty two bit unsigned integer (quint32)
@ Advanced
Parameter is an advanced parameter which should be hidden from users by default.
This class represents a coordinate reference system (CRS).
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
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 coordinate reference system parameter for processing algorithms.
A rectangular map extent parameter for processing algorithms.
A numeric parameter for processing algorithms.
A raster layer destination parameter, for specifying the destination path for a raster layer created ...
Raster data container.
static int typeSize(Qgis::DataType dataType)
Returns the size in bytes for the specified dataType.
static QString driverForExtension(const QString &extension)
Returns the GDAL driver name for a specified file extension.
A rectangle specified with double values.
double xMinimum() const
Returns the x minimum value (left side of rectangle).
double width() const
Returns the width of the rectangle.
double yMaximum() const
Returns the y maximum value (top side of rectangle).
double height() const
Returns the height of the rectangle.
const QgsCoordinateReferenceSystem & crs