QGIS API Documentation  3.23.0-Master (7c4a6de034)
qgsalgorithmrasterlayerproperties.cpp
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1 /***************************************************************************
2  qgsalgorithmrasterlayerproperties.cpp
3  ---------------------
4  begin : April 2021
5  copyright : (C) 2021 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 
19 #include "qgsstringutils.h"
20 
22 
23 QString QgsRasterLayerPropertiesAlgorithm::name() const
24 {
25  return QStringLiteral( "rasterlayerproperties" );
26 }
27 
28 QString QgsRasterLayerPropertiesAlgorithm::displayName() const
29 {
30  return QObject::tr( "Raster layer properties" );
31 }
32 
33 QStringList QgsRasterLayerPropertiesAlgorithm::tags() const
34 {
35  return QObject::tr( "extent,pixel,size,width,height" ).split( ',' );
36 }
37 
38 QString QgsRasterLayerPropertiesAlgorithm::group() const
39 {
40  return QObject::tr( "Raster analysis" );
41 }
42 
43 QString QgsRasterLayerPropertiesAlgorithm::groupId() const
44 {
45  return QStringLiteral( "rasteranalysis" );
46 }
47 
48 void QgsRasterLayerPropertiesAlgorithm::initAlgorithm( const QVariantMap & )
49 {
50  addParameter( new QgsProcessingParameterRasterLayer( QStringLiteral( "INPUT" ),
51  QObject::tr( "Input layer" ) ) );
52  addParameter( new QgsProcessingParameterBand( QStringLiteral( "BAND" ),
53  QObject::tr( "Band number" ), QVariant(), QStringLiteral( "INPUT" ), true ) );
54 
55  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "X_MIN" ), QObject::tr( "Minimum x-coordinate" ) ) );
56  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "X_MAX" ), QObject::tr( "Maximum x-coordinate" ) ) );
57  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "Y_MIN" ), QObject::tr( "Minimum y-coordinate" ) ) );
58  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "Y_MAX" ), QObject::tr( "Maximum y-coordinate" ) ) );
59  addOutput( new QgsProcessingOutputString( QStringLiteral( "EXTENT" ), QObject::tr( "Extent" ) ) );
60  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "PIXEL_WIDTH" ), QObject::tr( "Pixel size (width) in map units" ) ) );
61  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "PIXEL_HEIGHT" ), QObject::tr( "Pixel size (height) in map units" ) ) );
62  addOutput( new QgsProcessingOutputString( QStringLiteral( "CRS_AUTHID" ), QObject::tr( "CRS authority identifier" ) ) );
63  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "WIDTH_IN_PIXELS" ), QObject::tr( "Width in pixels" ) ) );
64  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "HEIGHT_IN_PIXELS" ), QObject::tr( "Height in pixels" ) ) );
65  addOutput( new QgsProcessingOutputBoolean( QStringLiteral( "HAS_NODATA_VALUE" ), QObject::tr( "Band has a nodata value set" ) ) );
66  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "NODATA_VALUE" ), QObject::tr( "Band nodata value" ) ) );
67  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "BAND_COUNT" ), QObject::tr( "Number of bands in raster" ) ) );
68 }
69 
70 QString QgsRasterLayerPropertiesAlgorithm::shortHelpString() const
71 {
72  return QObject::tr( "This algorithm returns basic properties of the given raster layer, including the extent, size in pixels and dimensions of pixels (in map units).\n\n"
73  "If an optional band number is specified then the nodata value for the selected band will also be returned." );
74 }
75 
76 QgsRasterLayerPropertiesAlgorithm *QgsRasterLayerPropertiesAlgorithm::createInstance() const
77 {
78  return new QgsRasterLayerPropertiesAlgorithm();
79 }
80 
81 bool QgsRasterLayerPropertiesAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
82 {
83  QgsRasterLayer *layer = parameterAsRasterLayer( parameters, QStringLiteral( "INPUT" ), context );
84 
85  if ( !layer )
86  throw QgsProcessingException( invalidRasterError( parameters, QStringLiteral( "INPUT" ) ) );
87 
88  mBandCount = layer->bandCount();
89 
90  if ( parameters.value( QStringLiteral( "BAND" ) ).isValid() )
91  {
92  const int band = parameterAsInt( parameters, QStringLiteral( "BAND" ), context );
93  if ( band < 1 || band > mBandCount )
94  throw QgsProcessingException( QObject::tr( "Invalid band number for BAND (%1): Valid values for input raster are 1 to %2" ).arg( band )
95  .arg( layer->bandCount() ) );
96  mHasNoDataValue = layer->dataProvider()->sourceHasNoDataValue( band );
97  if ( mHasNoDataValue )
98  mNoDataValue = layer->dataProvider()->sourceNoDataValue( band );
99  }
100 
101  mLayerWidth = layer->width();
102  mLayerHeight = layer->height();
103  mExtent = layer->extent();
104  mCrs = layer->crs();
105  mRasterUnitsPerPixelX = layer->rasterUnitsPerPixelX();
106  mRasterUnitsPerPixelY = layer->rasterUnitsPerPixelY();
107 
108  return true;
109 }
110 
111 QVariantMap QgsRasterLayerPropertiesAlgorithm::processAlgorithm( const QVariantMap &, QgsProcessingContext &, QgsProcessingFeedback * )
112 {
113  QVariantMap outputs;
114  outputs.insert( QStringLiteral( "EXTENT" ), mExtent.toString() );
115  outputs.insert( QStringLiteral( "X_MIN" ), mExtent.xMinimum() );
116  outputs.insert( QStringLiteral( "X_MAX" ), mExtent.xMaximum() );
117  outputs.insert( QStringLiteral( "Y_MIN" ), mExtent.yMinimum() );
118  outputs.insert( QStringLiteral( "Y_MAX" ), mExtent.yMaximum() );
119 
120  outputs.insert( QStringLiteral( "PIXEL_WIDTH" ), mRasterUnitsPerPixelX );
121  outputs.insert( QStringLiteral( "PIXEL_HEIGHT" ), mRasterUnitsPerPixelY );
122 
123  outputs.insert( QStringLiteral( "CRS_AUTHID" ), mCrs.authid() );
124  outputs.insert( QStringLiteral( "WIDTH_IN_PIXELS" ), mLayerWidth );
125  outputs.insert( QStringLiteral( "HEIGHT_IN_PIXELS" ), mLayerHeight );
126 
127  outputs.insert( QStringLiteral( "HAS_NODATA_VALUE" ), mHasNoDataValue );
128  if ( mHasNoDataValue )
129  outputs.insert( QStringLiteral( "NODATA_VALUE" ), mNoDataValue );
130  outputs.insert( QStringLiteral( "BAND_COUNT" ), mBandCount );
131 
132  return outputs;
133 }
134 
135 
137 
138 
139 
virtual QgsRectangle extent() const
Returns the extent of the layer.
QgsCoordinateReferenceSystem crs
Definition: qgsmaplayer.h:79
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 boolean output for processing algorithms.
A numeric output for processing algorithms.
A string output for processing algorithms.
A raster band parameter for Processing algorithms.
A raster layer parameter for processing algorithms.
virtual bool sourceHasNoDataValue(int bandNo) const
Returns true if source band has no data value.
virtual double sourceNoDataValue(int bandNo) const
Value representing no data value.
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.
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.
int width() const
Returns the width of the (unclipped) raster.