QGIS API Documentation 3.39.0-Master (3783037d301)
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qgsalgorithmslope.cpp
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1/***************************************************************************
2 qgsalgorithmslope.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 "qgsalgorithmslope.h"
19#include "qgsrasterfilewriter.h"
20#include "qgsslopefilter.h"
21
23
24QString QgsSlopeAlgorithm::name() const
25{
26 return QStringLiteral( "slope" );
27}
28
29QString QgsSlopeAlgorithm::displayName() const
30{
31 return QObject::tr( "Slope" );
32}
33
34QStringList QgsSlopeAlgorithm::tags() const
35{
36 return QObject::tr( "dem,slope,terrain" ).split( ',' );
37}
38
39QString QgsSlopeAlgorithm::group() const
40{
41 return QObject::tr( "Raster terrain analysis" );
42}
43
44QString QgsSlopeAlgorithm::groupId() const
45{
46 return QStringLiteral( "rasterterrainanalysis" );
47}
48
49QString QgsSlopeAlgorithm::shortHelpString() const
50{
51 return QObject::tr( "This algorithm calculates the angle of inclination "
52 "of the terrain from an input raster layer. The slope "
53 "is expressed in degrees." );
54}
55
56QgsSlopeAlgorithm *QgsSlopeAlgorithm::createInstance() const
57{
58 return new QgsSlopeAlgorithm();
59}
60
61void QgsSlopeAlgorithm::initAlgorithm( const QVariantMap & )
62{
63 addParameter( new QgsProcessingParameterRasterLayer( QStringLiteral( "INPUT" ), QObject::tr( "Elevation layer" ) ) );
64 addParameter( new QgsProcessingParameterNumber( QStringLiteral( "Z_FACTOR" ), QObject::tr( "Z factor" ),
66
67 addParameter( new QgsProcessingParameterRasterDestination( QStringLiteral( "OUTPUT" ), QObject::tr( "Slope" ) ) );
68}
69
70QVariantMap QgsSlopeAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
71{
72 QgsRasterLayer *inputLayer = parameterAsRasterLayer( parameters, QStringLiteral( "INPUT" ), context );
73
74 if ( !inputLayer )
75 throw QgsProcessingException( invalidRasterError( parameters, QStringLiteral( "INPUT" ) ) );
76
77 const double zFactor = parameterAsDouble( parameters, QStringLiteral( "Z_FACTOR" ), context );
78
79 const QString outputFile = parameterAsOutputLayer( parameters, QStringLiteral( "OUTPUT" ), context );
80 const QFileInfo fi( outputFile );
81 const QString outputFormat = QgsRasterFileWriter::driverForExtension( fi.suffix() );
82
83 QgsSlopeFilter slope( inputLayer->source(), outputFile, outputFormat );
84 slope.setZFactor( zFactor );
85 slope.processRaster( feedback );
86
87 QVariantMap outputs;
88 outputs.insert( QStringLiteral( "OUTPUT" ), outputFile );
89 return outputs;
90}
91
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.
Calculates slope values in a window of 3x3 cells based on first order derivatives in x- and y- direct...