QGIS API Documentation  3.23.0-Master (7c4a6de034)
qgsalgorithmvectorize.cpp
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1 /***************************************************************************
2  qgsalgorithmvectorize.cpp
3  ---------------------
4  begin : June, 2018
5  copyright : (C) 2018 by Nyall Dawson
6  email : nyall dot dawson 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 "qgsalgorithmvectorize.h"
19 #include "qgis.h"
20 #include "qgsprocessing.h"
21 
23 
24 QString QgsVectorizeAlgorithmBase::group() const
25 {
26  return QObject::tr( "Vector creation" );
27 }
28 
29 QString QgsVectorizeAlgorithmBase::groupId() const
30 {
31  return QStringLiteral( "vectorcreation" );
32 }
33 
34 void QgsVectorizeAlgorithmBase::initAlgorithm( const QVariantMap & )
35 {
36  addParameter( new QgsProcessingParameterRasterLayer( QStringLiteral( "INPUT_RASTER" ),
37  QObject::tr( "Raster layer" ) ) );
38  addParameter( new QgsProcessingParameterBand( QStringLiteral( "RASTER_BAND" ),
39  QObject::tr( "Band number" ), 1, QStringLiteral( "INPUT_RASTER" ) ) );
40  addParameter( new QgsProcessingParameterString( QStringLiteral( "FIELD_NAME" ),
41  QObject::tr( "Field name" ), QStringLiteral( "VALUE" ) ) );
42 
43  addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), outputName(), outputType() ) );
44 }
45 
46 bool QgsVectorizeAlgorithmBase::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
47 {
48  QgsRasterLayer *layer = parameterAsRasterLayer( parameters, QStringLiteral( "INPUT_RASTER" ), context );
49 
50  if ( !layer )
51  throw QgsProcessingException( invalidRasterError( parameters, QStringLiteral( "INPUT_RASTER" ) ) );
52 
53  mBand = parameterAsInt( parameters, QStringLiteral( "RASTER_BAND" ), context );
54  if ( mBand < 1 || mBand > layer->bandCount() )
55  throw QgsProcessingException( QObject::tr( "Invalid band number for RASTER_BAND (%1): Valid values for input raster are 1 to %2" ).arg( mBand )
56  .arg( layer->bandCount() ) );
57 
58  mInterface.reset( layer->dataProvider()->clone() );
59  mExtent = layer->extent();
60  mCrs = layer->crs();
61  mRasterUnitsPerPixelX = std::abs( layer->rasterUnitsPerPixelX() );
62  mRasterUnitsPerPixelY = std::abs( layer->rasterUnitsPerPixelY() );
63  mNbCellsXProvider = mInterface->xSize();
64  mNbCellsYProvider = mInterface->ySize();
65  return true;
66 }
67 
68 QVariantMap QgsVectorizeAlgorithmBase::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
69 {
70  const QString fieldName = parameterAsString( parameters, QStringLiteral( "FIELD_NAME" ), context );
71  QgsFields fields;
72  fields.append( QgsField( fieldName, QVariant::Double, QString(), 20, 8 ) );
73 
74  QString dest;
75  std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, fields, sinkType(), mCrs ) );
76  if ( !sink )
77  throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
78 
79 
82 
83  QgsRasterIterator iter( mInterface.get() );
84  iter.startRasterRead( mBand, mNbCellsXProvider, mNbCellsYProvider, mExtent );
85 
86  const int nbBlocksWidth = static_cast< int >( std::ceil( 1.0 * mNbCellsXProvider / maxWidth ) );
87  const int nbBlocksHeight = static_cast< int >( std::ceil( 1.0 * mNbCellsYProvider / maxHeight ) );
88  const int nbBlocks = nbBlocksWidth * nbBlocksHeight;
89 
90  int iterLeft = 0;
91  int iterTop = 0;
92  int iterCols = 0;
93  int iterRows = 0;
94  std::unique_ptr< QgsRasterBlock > rasterBlock;
95  QgsRectangle blockExtent;
96  bool isNoData = false;
97  while ( iter.readNextRasterPart( mBand, iterCols, iterRows, rasterBlock, iterLeft, iterTop, &blockExtent ) )
98  {
99  if ( feedback )
100  feedback->setProgress( 100 * ( ( iterTop / maxHeight * nbBlocksWidth ) + iterLeft / maxWidth ) / nbBlocks );
101  if ( feedback && feedback->isCanceled() )
102  break;
103 
104  double currentY = blockExtent.yMaximum() - 0.5 * mRasterUnitsPerPixelY;
105 
106  for ( int row = 0; row < iterRows; row++ )
107  {
108  if ( feedback && feedback->isCanceled() )
109  break;
110 
111  double currentX = blockExtent.xMinimum() + 0.5 * mRasterUnitsPerPixelX;
112 
113  for ( int column = 0; column < iterCols; column++ )
114  {
115  const double value = rasterBlock->valueAndNoData( row, column, isNoData );
116  if ( !isNoData )
117  {
118  const QgsGeometry pixelRectGeometry = createGeometryForPixel( currentX, currentY, mRasterUnitsPerPixelX, mRasterUnitsPerPixelY );
119 
120  QgsFeature f;
121  f.setGeometry( pixelRectGeometry );
122  f.setAttributes( QgsAttributes() << value );
123  if ( !sink->addFeature( f, QgsFeatureSink::FastInsert ) )
124  throw QgsProcessingException( writeFeatureError( sink.get(), parameters, QStringLiteral( "OUTPUT" ) ) );
125  }
126  currentX += mRasterUnitsPerPixelX;
127  }
128  currentY -= mRasterUnitsPerPixelY;
129  }
130  }
131 
132  QVariantMap outputs;
133  outputs.insert( QStringLiteral( "OUTPUT" ), dest );
134  return outputs;
135 }
136 
137 //
138 // QgsRasterPixelsToPolygonsAlgorithm
139 //
140 
141 QString QgsRasterPixelsToPolygonsAlgorithm::name() const
142 {
143  return QStringLiteral( "pixelstopolygons" );
144 }
145 
146 QString QgsRasterPixelsToPolygonsAlgorithm::displayName() const
147 {
148  return QObject::tr( "Raster pixels to polygons" );
149 }
150 
151 QStringList QgsRasterPixelsToPolygonsAlgorithm::tags() const
152 {
153  return QObject::tr( "vectorize,polygonize,raster,convert,pixels" ).split( ',' );
154 }
155 
156 QString QgsRasterPixelsToPolygonsAlgorithm::shortHelpString() const
157 {
158  return QObject::tr( "This algorithm converts a raster layer to a vector layer, by creating polygon features "
159  "for each individual pixel's extent in the raster layer.\n\n"
160  "Any nodata pixels are skipped in the output." );
161 }
162 
163 QString QgsRasterPixelsToPolygonsAlgorithm::shortDescription() const
164 {
165  return QObject::tr( "Creates a vector layer of polygons corresponding to each pixel in a raster layer." );
166 }
167 
168 QgsRasterPixelsToPolygonsAlgorithm *QgsRasterPixelsToPolygonsAlgorithm::createInstance() const
169 {
170  return new QgsRasterPixelsToPolygonsAlgorithm();
171 }
172 
173 QString QgsRasterPixelsToPolygonsAlgorithm::outputName() const
174 {
175  return QObject::tr( "Vector polygons" );
176 }
177 
178 QgsProcessing::SourceType QgsRasterPixelsToPolygonsAlgorithm::outputType() const
179 {
181 }
182 
183 QgsWkbTypes::Type QgsRasterPixelsToPolygonsAlgorithm::sinkType() const
184 {
185  return QgsWkbTypes::Polygon;
186 }
187 
188 QgsGeometry QgsRasterPixelsToPolygonsAlgorithm::createGeometryForPixel( double centerX, double centerY, double pixelWidthX, double pixelWidthY ) const
189 {
190  const double hCellSizeX = pixelWidthX / 2.0;
191  const double hCellSizeY = pixelWidthY / 2.0;
192  return QgsGeometry::fromRect( QgsRectangle( centerX - hCellSizeX, centerY - hCellSizeY, centerX + hCellSizeX, centerY + hCellSizeY ) );
193 }
194 
195 
196 //
197 // QgsRasterPixelsToPointsAlgorithm
198 //
199 
200 QString QgsRasterPixelsToPointsAlgorithm::name() const
201 {
202  return QStringLiteral( "pixelstopoints" );
203 }
204 
205 QString QgsRasterPixelsToPointsAlgorithm::displayName() const
206 {
207  return QObject::tr( "Raster pixels to points" );
208 }
209 
210 QStringList QgsRasterPixelsToPointsAlgorithm::tags() const
211 {
212  return QObject::tr( "vectorize,polygonize,raster,convert,pixels,centers" ).split( ',' );
213 }
214 
215 QString QgsRasterPixelsToPointsAlgorithm::shortHelpString() const
216 {
217  return QObject::tr( "This algorithm converts a raster layer to a vector layer, by creating point features "
218  "for each individual pixel's center in the raster layer.\n\n"
219  "Any nodata pixels are skipped in the output." );
220 }
221 
222 QString QgsRasterPixelsToPointsAlgorithm::shortDescription() const
223 {
224  return QObject::tr( "Creates a vector layer of points corresponding to each pixel in a raster layer." );
225 }
226 
227 QgsRasterPixelsToPointsAlgorithm *QgsRasterPixelsToPointsAlgorithm::createInstance() const
228 {
229  return new QgsRasterPixelsToPointsAlgorithm();
230 }
231 
232 QString QgsRasterPixelsToPointsAlgorithm::outputName() const
233 {
234  return QObject::tr( "Vector points" );
235 }
236 
237 QgsProcessing::SourceType QgsRasterPixelsToPointsAlgorithm::outputType() const
238 {
240 }
241 
242 QgsWkbTypes::Type QgsRasterPixelsToPointsAlgorithm::sinkType() const
243 {
244  return QgsWkbTypes::Point;
245 }
246 
247 QgsGeometry QgsRasterPixelsToPointsAlgorithm::createGeometryForPixel( double centerX, double centerY, double, double ) const
248 {
249  return QgsGeometry( new QgsPoint( centerX, centerY ) );
250 }
251 
253 
254 
A vector of attributes.
Definition: qgsattributes.h:58
@ FastInsert
Use faster inserts, at the cost of updating the passed features to reflect changes made at the provid...
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition: qgsfeature.h:56
void setAttributes(const QgsAttributes &attrs)
Sets the feature's attributes.
Definition: qgsfeature.cpp:153
void setGeometry(const QgsGeometry &geometry)
Set the feature's geometry.
Definition: qgsfeature.cpp:163
bool isCanceled() const SIP_HOLDGIL
Tells whether the operation has been canceled already.
Definition: qgsfeedback.h:54
void setProgress(double progress)
Sets the current progress for the feedback object.
Definition: qgsfeedback.h:63
Encapsulate a field in an attribute table or data source.
Definition: qgsfield.h:51
Container of fields for a vector layer.
Definition: qgsfields.h:45
bool append(const QgsField &field, FieldOrigin origin=OriginProvider, int originIndex=-1)
Appends a field. The field must have unique name, otherwise it is rejected (returns false)
Definition: qgsfields.cpp:59
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:125
static QgsGeometry fromRect(const QgsRectangle &rect) SIP_HOLDGIL
Creates a new geometry from a QgsRectangle.
virtual QgsRectangle extent() const
Returns the extent of the layer.
QgsCoordinateReferenceSystem crs
Definition: qgsmaplayer.h:79
Point geometry type, with support for z-dimension and m-values.
Definition: qgspoint.h:49
Contains information about the context in which a processing algorithm is executed.
Custom exception class for processing related exceptions.
Definition: qgsexception.h:83
Base class for providing feedback from a processing algorithm.
A raster band parameter for Processing algorithms.
A feature sink output for processing algorithms.
A raster layer parameter for processing algorithms.
A string parameter for processing algorithms.
SourceType
Data source types enum.
Definition: qgsprocessing.h:46
@ TypeVectorPolygon
Vector polygon layers.
Definition: qgsprocessing.h:51
@ TypeVectorPoint
Vector point layers.
Definition: qgsprocessing.h:49
QgsRasterDataProvider * clone() const override=0
Clone itself, create deep copy.
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 bandCount() const
Returns the number of bands in this layer.
double rasterUnitsPerPixelX() const
Returns the number of raster units per each raster pixel in X axis.
QgsRasterDataProvider * dataProvider() override
Returns the source data provider.
double rasterUnitsPerPixelY() const
Returns the number of raster units per each raster pixel in Y axis.
A rectangle specified with double values.
Definition: qgsrectangle.h:42
double yMaximum() const SIP_HOLDGIL
Returns the y maximum value (top side of rectangle).
Definition: qgsrectangle.h:193
double xMinimum() const SIP_HOLDGIL
Returns the x minimum value (left side of rectangle).
Definition: qgsrectangle.h:188
Type
The WKB type describes the number of dimensions a geometry has.
Definition: qgswkbtypes.h:70