QGIS API Documentation  2.0.1-Dufour
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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( "", "", "" )
26 {
27 
28 }
29 
30 
31 QgsRuggednessFilter::~QgsRuggednessFilter()
32 {
33 
34 }
35 
36 float QgsRuggednessFilter::processNineCellWindow( float* x11, float* x21, float* x31,
37  float* x12, float* x22, float* x32, float* x13, float* x23, float* x33 )
38 {
39  //the formula would be that easy without nodata values...
40  /*
41  //return *x22; //test: write the raster value of the middle cell
42  float diff1 = *x11 - *x22;
43  float diff2 = *x21 - *x22;
44  float diff3 = *x31 - *x22;
45  float diff4 = *x12 - *x22;
46  float diff5 = *x32 - *x22;
47  float diff6 = *x13 - *x22;
48  float diff7 = *x23 - *x22;
49  float diff8 = *x33 - *x22;
50  return sqrt(diff1 * diff1 + diff2 * diff2 + diff3 * diff3 + diff4 * diff4 + diff5 * diff5 + diff6 * diff6 + diff7 * diff7 + diff8 * diff8);
51  */
52 
53  if ( *x22 == mInputNodataValue )
54  {
55  return mOutputNodataValue;
56  }
57 
58  double sum = 0;
59  if ( *x11 != mInputNodataValue )
60  {
61  sum += ( *x11 - *x22 ) * ( *x11 - *x22 );
62  }
63  if ( *x21 != mInputNodataValue )
64  {
65  sum += ( *x21 - *x22 ) * ( *x21 - *x22 );
66  }
67  if ( *x31 != mInputNodataValue )
68  {
69  sum += ( *x31 - *x22 ) * ( *x31 - *x22 );
70  }
71  if ( *x12 != mInputNodataValue )
72  {
73  sum += ( *x12 - *x22 ) * ( *x12 - *x22 );
74  }
75  if ( *x32 != mInputNodataValue )
76  {
77  sum += ( *x32 - *x22 ) * ( *x32 - *x22 );
78  }
79  if ( *x13 != mInputNodataValue )
80  {
81  sum += ( *x13 - *x22 ) * ( *x13 - *x22 );
82  }
83  if ( *x23 != mInputNodataValue )
84  {
85  sum += ( *x23 - *x22 ) * ( *x23 - *x22 );
86  }
87  if ( *x33 != mInputNodataValue )
88  {
89  sum += ( *x33 - *x22 ) * ( *x33 - *x22 );
90  }
91 
92  return sqrt( sum );
93 }
94 
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