QGIS API Documentation 3.38.0-Grenoble (exported)
Loading...
Searching...
No Matches
qgsalgorithmaspect.cpp
Go to the documentation of this file.
1/***************************************************************************
2 qgsalgorithmaspect.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 "qgsalgorithmaspect.h"
19#include "qgsrasterfilewriter.h"
20#include "qgsaspectfilter.h"
21
23
24QString QgsAspectAlgorithm::name() const
25{
26 return QStringLiteral( "aspect" );
27}
28
29QString QgsAspectAlgorithm::displayName() const
30{
31 return QObject::tr( "Aspect" );
32}
33
34QStringList QgsAspectAlgorithm::tags() const
35{
36 return QObject::tr( "dem,aspect,terrain" ).split( ',' );
37}
38
39QString QgsAspectAlgorithm::group() const
40{
41 return QObject::tr( "Raster terrain analysis" );
42}
43
44QString QgsAspectAlgorithm::groupId() const
45{
46 return QStringLiteral( "rasterterrainanalysis" );
47}
48
49QString QgsAspectAlgorithm::shortHelpString() const
50{
51 return QObject::tr( "This algorithm calculates the aspect of the Digital Terrain Model in input." )
52 + QStringLiteral( "\n\n" )
53 + QObject::tr( "The final aspect raster layer contains values from 0 to 360 that express "
54 "the slope direction: starting from North (0°) and continuing clockwise." );
55}
56
57QgsAspectAlgorithm *QgsAspectAlgorithm::createInstance() const
58{
59 return new QgsAspectAlgorithm();
60}
61
62void QgsAspectAlgorithm::initAlgorithm( const QVariantMap & )
63{
64 addParameter( new QgsProcessingParameterRasterLayer( QStringLiteral( "INPUT" ), QObject::tr( "Elevation layer" ) ) );
65 addParameter( new QgsProcessingParameterNumber( QStringLiteral( "Z_FACTOR" ), QObject::tr( "Z factor" ),
67
68 addParameter( new QgsProcessingParameterRasterDestination( QStringLiteral( "OUTPUT" ), QObject::tr( "Aspect" ) ) );
69}
70
71QVariantMap QgsAspectAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
72{
73 QgsRasterLayer *inputLayer = parameterAsRasterLayer( parameters, QStringLiteral( "INPUT" ), context );
74
75 if ( !inputLayer )
76 throw QgsProcessingException( invalidRasterError( parameters, QStringLiteral( "INPUT" ) ) );
77
78 const double zFactor = parameterAsDouble( parameters, QStringLiteral( "Z_FACTOR" ), context );
79
80 const QString outputFile = parameterAsOutputLayer( parameters, QStringLiteral( "OUTPUT" ), context );
81 const QFileInfo fi( outputFile );
82 const QString outputFormat = QgsRasterFileWriter::driverForExtension( fi.suffix() );
83
84 QgsAspectFilter aspect( inputLayer->source(), outputFile, outputFormat );
85 aspect.setZFactor( zFactor );
86 aspect.processRaster( feedback );
87
88 QVariantMap outputs;
89 outputs.insert( QStringLiteral( "OUTPUT" ), outputFile );
90 return outputs;
91}
92
Calculates aspect values in a window of 3x3 cells based on first order derivatives in x- and y- direc...
QString source() const
Returns the source for the layer.
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.
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.
static QString driverForExtension(const QString &extension)
Returns the GDAL driver name for a specified file extension.
Represents a raster layer.