📄 topographicindices.cpp
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///////////////////////////////////////////////////////////
// //
// SAGA //
// //
// System for Automated Geoscientific Analyses //
// //
// Module Library: //
// ta_hydrology //
// //
//-------------------------------------------------------//
// //
// TopographicIndices.cpp //
// //
// Copyright (C) 2003 by //
// Olaf Conrad //
// //
//-------------------------------------------------------//
// //
// This file is part of 'SAGA - System for Automated //
// Geoscientific Analyses'. SAGA is free software; you //
// can redistribute it and/or modify it under the terms //
// of the GNU General Public License as published by the //
// Free Software Foundation; version 2 of the License. //
// //
// SAGA is distributed in the hope that it will be //
// useful, but WITHOUT ANY WARRANTY; without even the //
// implied warranty of MERCHANTABILITY or FITNESS FOR A //
// PARTICULAR PURPOSE. See the GNU General Public //
// License for more details. //
// //
// You should have received a copy of the GNU General //
// Public License along with this program; if not, //
// write to the Free Software Foundation, Inc., //
// 59 Temple Place - Suite 330, Boston, MA 02111-1307, //
// USA. //
// //
//-------------------------------------------------------//
// //
// e-mail: oconrad@saga-gis.org //
// //
// contact: Olaf Conrad //
// Institute of Geography //
// University of Goettingen //
// Goldschmidtstr. 5 //
// 37077 Goettingen //
// Germany //
// //
///////////////////////////////////////////////////////////
//---------------------------------------------------------
///////////////////////////////////////////////////////////
// //
// //
// //
///////////////////////////////////////////////////////////
//---------------------------------------------------------
#include "TopographicIndices.h"
///////////////////////////////////////////////////////////
// //
// //
// //
///////////////////////////////////////////////////////////
//---------------------------------------------------------
CTopographicIndices::CTopographicIndices(void)
{
Set_Name(_TL("Topographic Indices"));
Set_Author(_TL("Copyrights (c) 2003 by Olaf Conrad"));
Set_Description (_TW(
"Calculation of slope and catchment area based topographic indices (wetness, LS-factor, stream power).\n\n"
"References:\n"
"Moore, I.D., Grayson, R.B., Ladson, A.R. (1991): "
"'Digital terrain modelling: a review of hydrogical, geomorphological, and biological applications'\n"
"Hydrological Processes, Vol.5, No.1\n")
);
//-----------------------------------------------------
Parameters.Add_Grid(
NULL, "SLOPE" , _TL("Slope"),
_TL(""),
PARAMETER_INPUT
);
Parameters.Add_Grid(
NULL, "AREA" , _TL("Catchment Area"),
_TL(""),
PARAMETER_INPUT
);
Parameters.Add_Grid(
NULL, "TRANSMISS" , _TL("Transmissivity"),
_TL(""),
PARAMETER_INPUT_OPTIONAL
);
//-----------------------------------------------------
Parameters.Add_Grid(
NULL, "WETNESS" , _TL("Topographic Wetness Index"),
_TL("The Topographic Wetness Index: ln( A / tan(\xc3\x9f) )"),
PARAMETER_OUTPUT
);
Parameters.Add_Grid(
NULL, "STREAMPOW" , _TL("Stream Power Index"),
_TL(""),
PARAMETER_OUTPUT_OPTIONAL
);
Parameters.Add_Grid(
NULL, "LSFACTOR" , _TL("LS-Factor"),
_TL(""),
PARAMETER_OUTPUT_OPTIONAL
);
}
//---------------------------------------------------------
CTopographicIndices::~CTopographicIndices(void)
{}
///////////////////////////////////////////////////////////
// //
// //
// //
///////////////////////////////////////////////////////////
//---------------------------------------------------------
bool CTopographicIndices::On_Execute(void)
{
bool bTopmodel = false;
int x, y;
double Area, Slope, tan_Slope, Kf, Mean_Kf, Mean_TWI;
CSG_Grid *pArea, *pSlope, *pKf, *pTWI, *pSPI, *pLSF;
//-----------------------------------------------------
pSlope = Parameters("SLOPE") ->asGrid();
pArea = Parameters("AREA") ->asGrid();
pKf = Parameters("TRANSMISS") ->asGrid();
pTWI = Parameters("WETNESS") ->asGrid();
pSPI = Parameters("STREAMPOW") ->asGrid();
pLSF = Parameters("LSFACTOR") ->asGrid();
Kf = 1.0;
if( pTWI )
{
DataObject_Set_Colors(pTWI, 100, SG_COLORS_RED_GREY_BLUE);
}
if( pSPI )
{
DataObject_Set_Colors(pSPI, 100, SG_COLORS_RED_GREY_GREEN, true);
}
if( pLSF )
{
DataObject_Set_Colors(pLSF, 100, SG_COLORS_RED_GREY_GREEN, true);
}
//-----------------------------------------------------
if( bTopmodel )
{
Mean_TWI = 0.0;
Mean_Kf = 0.0;
Area = 0.0;
for(y=0; y<Get_NY() && Set_Progress(y); y++)
{
for(x=0; x<Get_NX(); x++)
{
if( !pArea->is_NoData(x, y) && !pSlope->is_NoData(x, y) )
{
if( pKf )
{
if( !pKf->is_NoData(x, y) )
{
Kf = pKf->asDouble(x, y);
if( Kf < M_ALMOST_ZERO ) Kf = M_ALMOST_ZERO;
Kf = log(Kf);
}
else
{
Kf = 0.0;
}
}
tan_Slope = tan(pSlope->asDouble(x, y));
if( tan_Slope < M_ALMOST_ZERO ) tan_Slope = M_ALMOST_ZERO;
Mean_TWI += log(pArea->asDouble(x, y) / tan_Slope);
Mean_Kf += Kf;
Area++;
}
}
}
if( Area > 0.0 )
{
Area *= pArea->Get_Cellarea();
Mean_TWI /= Area;
Mean_Kf /= Area;
}
}
//-----------------------------------------------------
for(y=0; y<Get_NY() && Set_Progress(y); y++)
{
for(x=0; x<Get_NX(); x++)
{
if( pArea->is_NoData(x, y) || pSlope->is_NoData(x, y) )
{
if( pLSF ) pLSF->Set_NoData(x, y);
if( pSPI ) pSPI->Set_NoData(x, y);
if( pTWI ) pTWI->Set_NoData(x, y);
}
else
{
//-----------------------------------------
Area = pArea ->asDouble(x, y) / pArea->Get_Cellsize(); // pseudo specific catchment area...
Slope = pSlope->asDouble(x, y); // slope as radians...
tan_Slope = tan(Slope);
if( tan_Slope < M_ALMOST_ZERO ) tan_Slope = M_ALMOST_ZERO;
if( pKf )
{
Kf = pKf->asDouble(x, y);
if( Kf < M_ALMOST_ZERO ) Kf = M_ALMOST_ZERO;
}
//-----------------------------------------
if( pLSF )
{
pLSF->Set_Value(x, y,
(0.4 + 1) * pow(Area / 22.13, 0.4) * pow(sin(Slope) / 0.0896, 1.3)
);
}
if( pSPI )
{
pSPI->Set_Value(x, y,
Area * tan_Slope
);
}
if( pTWI )
{
pTWI->Set_Value(x, y, bTopmodel
? (log(Area / ( tan_Slope)) - Mean_TWI) - (log(Kf) - Mean_Kf)
: log(Area / (Kf * tan_Slope))
);
}
}
}
}
return( true );
}
///////////////////////////////////////////////////////////
// //
// //
// //
///////////////////////////////////////////////////////////
//---------------------------------------------------------
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