QGIS API Documentation  2.99.0-Master (5b186ae)
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 
20 QgsRuggednessFilter::QgsRuggednessFilter( const QString &inputFile, const QString &outputFile, const QString &outputFormat ): QgsNineCellFilter( inputFile, outputFile, outputFormat )
21 {
22 
23 }
24 
25 QgsRuggednessFilter::QgsRuggednessFilter(): QgsNineCellFilter( QLatin1String( "" ), QLatin1String( "" ), QLatin1String( "" ) )
26 {
27 
28 }
29 
30 float QgsRuggednessFilter::processNineCellWindow( float *x11, float *x21, float *x31,
31  float *x12, float *x22, float *x32, float *x13, float *x23, float *x33 )
32 {
33  //the formula would be that easy without nodata values...
34  /*
35  //return *x22; //test: write the raster value of the middle cell
36  float diff1 = *x11 - *x22;
37  float diff2 = *x21 - *x22;
38  float diff3 = *x31 - *x22;
39  float diff4 = *x12 - *x22;
40  float diff5 = *x32 - *x22;
41  float diff6 = *x13 - *x22;
42  float diff7 = *x23 - *x22;
43  float diff8 = *x33 - *x22;
44  return sqrt(diff1 * diff1 + diff2 * diff2 + diff3 * diff3 + diff4 * diff4 + diff5 * diff5 + diff6 * diff6 + diff7 * diff7 + diff8 * diff8);
45  */
46 
47  if ( *x22 == mInputNodataValue )
48  {
49  return mOutputNodataValue;
50  }
51 
52  double sum = 0;
53  if ( *x11 != mInputNodataValue )
54  {
55  sum += ( *x11 - *x22 ) * ( *x11 - *x22 );
56  }
57  if ( *x21 != mInputNodataValue )
58  {
59  sum += ( *x21 - *x22 ) * ( *x21 - *x22 );
60  }
61  if ( *x31 != mInputNodataValue )
62  {
63  sum += ( *x31 - *x22 ) * ( *x31 - *x22 );
64  }
65  if ( *x12 != mInputNodataValue )
66  {
67  sum += ( *x12 - *x22 ) * ( *x12 - *x22 );
68  }
69  if ( *x32 != mInputNodataValue )
70  {
71  sum += ( *x32 - *x22 ) * ( *x32 - *x22 );
72  }
73  if ( *x13 != mInputNodataValue )
74  {
75  sum += ( *x13 - *x22 ) * ( *x13 - *x22 );
76  }
77  if ( *x23 != mInputNodataValue )
78  {
79  sum += ( *x23 - *x22 ) * ( *x23 - *x22 );
80  }
81  if ( *x33 != mInputNodataValue )
82  {
83  sum += ( *x33 - *x22 ) * ( *x33 - *x22 );
84  }
85 
86  return sqrt( sum );
87 }
88 
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...