1
2 ///////////////////////////////////////////////////////////
3 // //
4 // SAGA //
5 // //
6 // System for Automated Geoscientific Analyses //
7 // //
8 // Tool Library //
9 // Grid_Calculus //
10 // //
11 //-------------------------------------------------------//
12 // //
13 // grid_histogram_match.cpp //
14 // //
15 // Copyright (C) 2019 by //
16 // Olaf Conrad //
17 // //
18 //-------------------------------------------------------//
19 // //
20 // This file is part of 'SAGA - System for Automated //
21 // Geoscientific Analyses'. SAGA is free software; you //
22 // can redistribute it and/or modify it under the terms //
23 // of the GNU General Public License as published by the //
24 // Free Software Foundation, either version 2 of the //
25 // License, or (at your option) any later version. //
26 // //
27 // SAGA is distributed in the hope that it will be //
28 // useful, but WITHOUT ANY WARRANTY; without even the //
29 // implied warranty of MERCHANTABILITY or FITNESS FOR A //
30 // PARTICULAR PURPOSE. See the GNU General Public //
31 // License for more details. //
32 // //
33 // You should have received a copy of the GNU General //
34 // Public License along with this program; if not, see //
35 // <http://www.gnu.org/licenses/>. //
36 // //
37 //-------------------------------------------------------//
38 // //
39 // e-mail: oconrad@saga-gis.org //
40 // //
41 // contact: Olaf Conrad //
42 // Institute of Geography //
43 // University of Hamburg //
44 // Germany //
45 // //
46 ///////////////////////////////////////////////////////////
47
48 //---------------------------------------------------------
49 #include "grid_histogram_match.h"
50
51
52 ///////////////////////////////////////////////////////////
53 // //
54 // //
55 // //
56 ///////////////////////////////////////////////////////////
57
58 //---------------------------------------------------------
CGrid_Histogram_Match(void)59 CGrid_Histogram_Match::CGrid_Histogram_Match(void)
60 {
61 Set_Name (_TL("Histogram Matching"));
62
63 Set_Author ("O.Conrad (c) 2019");
64
65 Set_Description (_TW(
66 "This tool alters the values of a grid so that its value "
67 "distribution (its histogram), matches that of a reference grid. "
68 "The first method simply uses arithmetic mean and standard "
69 "deviation for adjustment, which usually is sufficient for normal "
70 "distributed values. The second method performs a more precise "
71 "adjustment based on the grids' histograms. "
72 ));
73
74 Parameters.Add_Grid(
75 "", "GRID" , _TL("Grid"),
76 _TL(""),
77 PARAMETER_INPUT
78 );
79
80 Parameters.Add_Grid(
81 "", "MATCHED" , _TL("Adjusted Grid"),
82 _TL(""),
83 PARAMETER_OUTPUT_OPTIONAL
84 );
85
86 Parameters.Add_Grid(
87 "", "REFERENCE" , _TL("Reference Grid"),
88 _TL(""),
89 PARAMETER_INPUT, false
90 );
91
92 Parameters.Add_Choice(
93 "", "METHOD" , _TL("Method"),
94 _TL(""),
95 CSG_String::Format("%s|%s",
96 _TL("standard deviation"),
97 _TL("histogram")
98 ), 1
99 );
100
101 Parameters.Add_Int(
102 "", "NCLASSES" , _TL("Histogramm Classes"),
103 _TL("Number of histogram classes for internal use."),
104 10, 100, true
105 );
106
107 Parameters.Add_Int(
108 "", "MAXSAMPLES", _TL("Maximum Sample Size"),
109 _TL("If set to zero all data will be used to build the histograms."),
110 1000000, 0, true
111 );
112 }
113
114
115 ///////////////////////////////////////////////////////////
116 // //
117 ///////////////////////////////////////////////////////////
118
119 //---------------------------------------------------------
On_Parameters_Enable(CSG_Parameters * pParameters,CSG_Parameter * pParameter)120 int CGrid_Histogram_Match::On_Parameters_Enable(CSG_Parameters *pParameters, CSG_Parameter *pParameter)
121 {
122 if( pParameter->Cmp_Identifier("METHOD") )
123 {
124 pParameters->Set_Enabled("NCLASSES" , pParameter->asInt() == 1);
125 pParameters->Set_Enabled("MAXSAMPLES", pParameter->asInt() == 1);
126 }
127
128 return( CSG_Tool_Grid::On_Parameters_Enable(pParameters, pParameter) );
129 }
130
131
132 ///////////////////////////////////////////////////////////
133 // //
134 ///////////////////////////////////////////////////////////
135
136 //---------------------------------------------------------
On_Execute(void)137 bool CGrid_Histogram_Match::On_Execute(void)
138 {
139 //-----------------------------------------------------
140 CSG_Grid *pGrid = Parameters("GRID")->asGrid();
141
142 if( Parameters("MATCHED")->asGrid() && Parameters("MATCHED")->asGrid() != pGrid )
143 {
144 CSG_Grid *pResult = Parameters("MATCHED")->asGrid();
145
146 pResult->Create(*pGrid);
147
148 pResult->Fmt_Name("%s [%s]", pGrid->Get_Name(), _TL("histogram match"));
149
150 pGrid = pResult;
151 }
152
153 //-----------------------------------------------------
154 CSG_Grid *pReference = Parameters("REFERENCE")->asGrid();
155
156 CSG_Simple_Statistics Statistics[2]; CSG_Histogram Histogram[2];
157
158 int Method = Parameters("METHOD")->asInt();
159
160 switch( Method )
161 {
162 case 0:
163 Statistics[0] = pReference->Get_Statistics();
164
165 if( Statistics[0].Get_StdDev() <= 0.0 )
166 {
167 Error_Fmt("%s [%s]", _TL("no variance in data set"), pReference->Get_Name());
168
169 return( false );
170 }
171
172 Statistics[1] = pGrid->Get_Statistics();
173
174 if( Statistics[1].Get_StdDev() <= 0.0 )
175 {
176 Error_Fmt("%s [%s]", _TL("no variance in data set"), pGrid->Get_Name());
177
178 return( false );
179 }
180 break;
181
182 default:
183 if( !Histogram[0].Create(Parameters("NCLASSES")->asInt(),
184 pReference->Get_Min(), pReference->Get_Max(), pReference, (size_t)Parameters("MAXSAMPLES")->asInt()) )
185 {
186 Error_Fmt("%s [%s]", _TL("failed to create histogram"), pReference->Get_Name());
187
188 return( false );
189 }
190
191 if( !Histogram[1].Create(Parameters("NCLASSES")->asInt(),
192 pGrid->Get_Min(), pGrid->Get_Max(), pGrid, (size_t)Parameters("MAXSAMPLES")->asInt()) )
193 {
194 Error_Fmt("%s [%s]", _TL("failed to create histogram"), pGrid->Get_Name());
195
196 return( false );
197 }
198 break;
199 }
200
201 //-----------------------------------------------------
202 for(int y=0; y<Get_NY() && Set_Progress(y); y++)
203 {
204 #ifndef _DEBUG
205 #pragma omp parallel for
206 #endif
207 for(int x=0; x<Get_NX(); x++)
208 {
209 if( !pGrid->is_NoData(x, y) )
210 {
211 double v = pGrid->asDouble(x, y);
212
213 switch( Method )
214 {
215 case 0:
216 v = Statistics[0].Get_Mean() + (v - Statistics[1].Get_Mean()) * Statistics[0].Get_StdDev() / Statistics[1].Get_StdDev();
217 break;
218
219 default:
220 v = Histogram[0].Get_Quantile(Histogram[1].Get_Quantile_Value(v));
221 break;
222 }
223
224 pGrid->Set_Value(x, y, v);
225 }
226 }
227 }
228
229 //-----------------------------------------------------
230 if( pGrid != Parameters("MATCHED")->asGrid() )
231 {
232 DataObject_Update(pGrid); // only declared output data is updated automatically by the framework
233 }
234
235 return( true );
236 }
237
238
239 ///////////////////////////////////////////////////////////
240 // //
241 // //
242 // //
243 ///////////////////////////////////////////////////////////
244
245 //---------------------------------------------------------
246