QGIS API Documentation  2.99.0-Master (9caa722)
qgsruggednessfilter.cpp
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1 /***************************************************************************
2  qgsruggednessfilter.cpp - description
3  -----------------------
4  begin : August 7th, 2009
5  copyright : (C) 2009 by Marco Hugentobler
6  email : marco dot hugentobler at karto dot baug dot ethz dot ch
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 "qgsruggednessfilter.h"
19 #include <cmath>
20 
21 QgsRuggednessFilter::QgsRuggednessFilter( const QString &inputFile, const QString &outputFile, const QString &outputFormat ): QgsNineCellFilter( inputFile, outputFile, outputFormat )
22 {
23 
24 }
25 
26 QgsRuggednessFilter::QgsRuggednessFilter(): QgsNineCellFilter( QLatin1String( "" ), QLatin1String( "" ), QLatin1String( "" ) )
27 {
28 
29 }
30 
31 float QgsRuggednessFilter::processNineCellWindow( float *x11, float *x21, float *x31,
32  float *x12, float *x22, float *x32, float *x13, float *x23, float *x33 )
33 {
34  //the formula would be that easy without nodata values...
35  /*
36  //return *x22; //test: write the raster value of the middle cell
37  float diff1 = *x11 - *x22;
38  float diff2 = *x21 - *x22;
39  float diff3 = *x31 - *x22;
40  float diff4 = *x12 - *x22;
41  float diff5 = *x32 - *x22;
42  float diff6 = *x13 - *x22;
43  float diff7 = *x23 - *x22;
44  float diff8 = *x33 - *x22;
45  return sqrt(diff1 * diff1 + diff2 * diff2 + diff3 * diff3 + diff4 * diff4 + diff5 * diff5 + diff6 * diff6 + diff7 * diff7 + diff8 * diff8);
46  */
47 
48  if ( *x22 == mInputNodataValue )
49  {
50  return mOutputNodataValue;
51  }
52 
53  double sum = 0;
54  if ( *x11 != mInputNodataValue )
55  {
56  sum += ( *x11 - *x22 ) * ( *x11 - *x22 );
57  }
58  if ( *x21 != mInputNodataValue )
59  {
60  sum += ( *x21 - *x22 ) * ( *x21 - *x22 );
61  }
62  if ( *x31 != mInputNodataValue )
63  {
64  sum += ( *x31 - *x22 ) * ( *x31 - *x22 );
65  }
66  if ( *x12 != mInputNodataValue )
67  {
68  sum += ( *x12 - *x22 ) * ( *x12 - *x22 );
69  }
70  if ( *x32 != mInputNodataValue )
71  {
72  sum += ( *x32 - *x22 ) * ( *x32 - *x22 );
73  }
74  if ( *x13 != mInputNodataValue )
75  {
76  sum += ( *x13 - *x22 ) * ( *x13 - *x22 );
77  }
78  if ( *x23 != mInputNodataValue )
79  {
80  sum += ( *x23 - *x22 ) * ( *x23 - *x22 );
81  }
82  if ( *x33 != mInputNodataValue )
83  {
84  sum += ( *x33 - *x22 ) * ( *x33 - *x22 );
85  }
86 
87  return std::sqrt( sum );
88 }
89 
float processNineCellWindow(float *x11, float *x21, float *x31, float *x12, float *x22, float *x32, float *x13, float *x23, float *x33) override
Calculates output value from nine input values.
QgsRuggednessFilter(const QString &inputFile, const QString &outputFile, const QString &outputFormat)
float mOutputNodataValue
The nodata value of the output layer.
float mInputNodataValue
The nodata value of the input layer.
Base class for raster analysis methods that work with a 3x3 cell filter and calculate the value of ea...