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/***********************************************/
/**
* @file griddedDataReduceSampling.cpp
*
* @brief Generate coarse grid by computing mean values.
*
* @author Torsten Mayer-Guerr
* @date 2013-10-24
*/
/***********************************************/
// Latex documentation
#define DOCSTRING docstring
static const char *docstring = R"(
Generate coarse grid by computing area weighted mean values.
The number of points is decimated by averaging integer multiplies of grid points
(\config{multiplierLongitude}, \config{multiplierLatitude}).
if \config{volumeConserving} is set, data are interpreted as heights above ellipsoid
and the tesseroid volume
\begin{equation}
V=\int_r^{r+H}\int_{\varphi_1}^{\varphi_2}\int_{\lambda_1}^{\lambda_2} r^2\cos\varphi\,d\varphi\,d\lambda\,dr
\end{equation}
is conserved, where $r$ is the radius of the ellipsoid at grid center and
$(\varphi_1-\varphi_2)\times(\lambda_1-\lambda_2)$ are the grid cell boundaries.
This is meaninful for Digital Elevation Models (DEM).
The fine grid can be written, where the first coarse grid values (data0) are additionally appended.
)";
/***********************************************/
#include "programs/program.h"
#include "files/fileGriddedData.h"
#include "misc/miscGriddedData.h"
/***** CLASS ***********************************/
/** @brief Generate coarse grid by computing mean values.
* @ingroup programsGroup */
class GriddedDataReduceSampling
{
public:
void run(Config &config, Parallel::CommunicatorPtr comm);
};
GROOPS_REGISTER_PROGRAM(GriddedDataReduceSampling, SINGLEPROCESS, "Generate coarse grid by computing mean values", Grid)
/***********************************************/
void GriddedDataReduceSampling::run(Config &config, Parallel::CommunicatorPtr /*comm*/)
{
try
{
FileName fileNameOutCoarseGrid, fileNameOutFineGrid;
FileName fileNameInFineGrid;
UInt numberRows, numberCols;
Bool volumeConserving;
readConfig(config, "outputfileCoarseGridRectangular", fileNameOutCoarseGrid, Config::OPTIONAL, "", "coarse grid");
readConfig(config, "outputfileFineGridRectangular", fileNameOutFineGrid, Config::OPTIONAL, "", "fine grid with additional coarse grid values");
readConfig(config, "inputfileFineGridRectangular", fileNameInFineGrid, Config::MUSTSET, "", "Digital Terrain Model");
readConfig(config, "multiplierLongitude", numberCols, Config::MUSTSET, "8", "Generalizing factor");
readConfig(config, "multiplierLatitude", numberRows, Config::MUSTSET, "8", "Generalizing factor");
readConfig(config, "volumeConserving", volumeConserving, Config::DEFAULT, "0", "data are interpreted as heights above ellipsoid");
if(isCreateSchema(config)) return;
// read grid
// ---------
logStatus<<"read grid from file <"<<fileNameInFineGrid<<">"<<Log::endl;
GriddedDataRectangular gridFine;
readFileGriddedData(fileNameInFineGrid, gridFine);
std::vector<Angle> tmp;
std::vector<Double> radiusFine, longitude, latitude, dLambda, dPhi;
gridFine.geocentric(tmp, tmp, radiusFine);
gridFine.cellBorders(longitude, latitude);
gridFine.areaElements(dLambda, dPhi);
// Generate coarse grid
// --------------------
logStatus<<"generate coarse grid"<<Log::endl;
GriddedDataRectangular gridCoarse;
gridCoarse.ellipsoid = gridFine.ellipsoid;
gridCoarse.latitudes.resize(gridFine.latitudes.size()/numberRows);
for(UInt i=0; i<gridCoarse.latitudes.size(); i++)
gridCoarse.latitudes.at(i) = 0.5*(latitude.at(i*numberRows) + latitude.at((i+1)*numberRows));
gridCoarse.longitudes.resize(gridFine.longitudes.size()/numberCols);
for(UInt k=0; k<gridCoarse.longitudes.size(); k++)
gridCoarse.longitudes.at(k) = std::remainder(longitude.at(k*numberCols) + 0.5*std::remainder(longitude.at((k+1)*numberCols)-longitude.at(k*numberCols), 2*PI), 2*PI);
gridCoarse.heights.resize(gridCoarse.latitudes.size()); // Compute mean height
for(UInt i=0; i<gridCoarse.heights.size(); i++)
{
Double height = 0, weight = 0;
for(UInt ii=0; ii<numberRows; ii++)
{
height += dPhi.at(i) * gridFine.heights.at(i*numberRows+ii);
weight += dPhi.at(i);
}
gridCoarse.heights.at(i) = height/weight;
}
gridCoarse.values.resize(gridFine.values.size(), Matrix(gridCoarse.latitudes.size(), gridCoarse.longitudes.size()));
std::vector<Double> radiusCoarse, dLambdaCoarse, dPhiCoarse;
gridCoarse.geocentric(tmp, tmp, radiusCoarse);
gridCoarse.areaElements(dLambdaCoarse, dPhiCoarse);
// Compute mean values
// -------------------
logStatus<<"compute mean values"<<Log::endl;
if(!fileNameOutFineGrid.empty())
gridFine.values.push_back(Matrix(gridFine.latitudes.size(), gridFine.longitudes.size()));
Single::forEach(gridCoarse.latitudes.size(), [&](UInt i)
{
for(UInt k=0; k<gridCoarse.longitudes.size(); k++)
{
// compute volume of tesseroid V = (r2^3-r1^3)/3 * area with r2=r1+h
Vector volumes(gridCoarse.values.size());
for(UInt ii=0; ii<numberRows; ii++)
for(UInt kk=0; kk<numberCols; kk++)
{
const Double area = dPhi.at(i*numberRows+ii) * dLambda.at(k*numberCols+kk);
const Double r1 = radiusFine.at(i*numberRows+ii);
for(UInt idx=0; idx<gridCoarse.values.size(); idx++)
if(volumeConserving)
volumes(idx) += area * (std::pow(r1+gridFine.values.at(idx)(i*numberRows+ii, k*numberCols+kk), 3) - std::pow(r1, 3))/3.;
else
volumes(idx) += area * gridFine.values.at(idx)(i*numberRows+ii, k*numberCols+kk);
}
// height of tesseroid = (V*3/area - r1^3)^(1/3) - r1
const Double area = dPhiCoarse.at(i) * dLambdaCoarse.at(k);
const Double r1 = radiusCoarse.at(i);
for(UInt idx=0; idx<gridCoarse.values.size(); idx++)
if(volumeConserving)
gridCoarse.values.at(idx)(i, k) = std::pow(volumes(idx)*3/area + std::pow(r1, 3), 1./3.) - r1;
else
gridCoarse.values.at(idx)(i, k) = volumes(idx)/area;
if(!fileNameOutFineGrid.empty())
for(UInt ii=0; ii<numberRows; ii++)
for(UInt kk=0; kk<numberCols; kk++)
gridFine.values.back()(i*numberRows+ii, k*numberCols+kk) = gridCoarse.values.at(0)(i, k);
}
});
// write new grid
// --------------
if(!fileNameOutCoarseGrid.empty())
{
logStatus<<"write coarse grid to file <"<<fileNameOutCoarseGrid<<">"<<Log::endl;
writeFileGriddedData(fileNameOutCoarseGrid, gridCoarse);
MiscGriddedData::printStatistics(gridCoarse);
}
if(!fileNameOutFineGrid.empty())
{
logStatus<<"write fine grid to file <"<<fileNameOutFineGrid<<">"<<Log::endl;
writeFileGriddedData(fileNameOutFineGrid, gridFine);
MiscGriddedData::printStatistics(gridFine);
}
}
catch(std::exception &e)
{
GROOPS_RETHROW(e)
}
}
/***********************************************/
|
