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Commit 52d0a190 authored by LEFEBVREJP email's avatar LEFEBVREJP email
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Fixing wind speed and direction for awr met source.

parent 09680b4b
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radixio/gfsfile.cc
View file @ 52d0a190
......@@ -270,6 +270,54 @@ std::pair<float, float> GFSFile::gbl2xy(float clat
return result;
}
std::pair<float, float> GFSFile::cnxyll(float xi, float eta) const
{
float gamma = mStrcmp[0];
float cgeta = 1.f - gamma * eta;
float gxi = gamma * xi;
// calculate equivalent mercator coordinate
float arg2 = eta + (eta*cgeta - gxi * xi);
float arg1 = gamma * arg2;
float xlat = 0, xlong = 0, temp = 0, ymerc = 0, along = 0;
// distance to north (or south) pole is zero (or imaginary)
if(arg1 >= 1.f)
{
xlat = std::copysign(90., mStrcmp[0]);
xlong = 90. + xlat;
return std::make_pair(xlat, xlong);
}
if(std::abs(arg1) < 0.01f)
{
// this avoids round-off error or divide-by zero in case of mercator projects
temp = std::pow(arg1 / (2.f - arg1), 2);
ymerc = arg2 / (2.f -arg1) * (1.f + temp *
(1.f/3.f + temp *
(1.f/5.f + temp *
1.f/7.f)));
} else
{
//code for moderate values of gamma
ymerc = - std::log(1.f-arg1) / 2.f / gamma;
}
// convert ymerc to latitude
temp = std::exp(- std::abs(ymerc));
xlat = std::copysign(std::atan2((1.f-temp)*(1.f+temp), 2.f*temp),ymerc);
// find longitudes
if(std::abs(gxi) < 0.01f*cgeta)
{ // this avoids round-off error or divide-by zero in case of mercator projects
temp = std::pow(gxi / cgeta, 2);
ymerc = xi / cgeta * (1.f - temp *
(1.f/3.f - temp *
(1.f/5.f - temp *
1.f/7.f)));
} else
{
along = std::atan2(gxi, cgeta) /gamma;
}
xlong = mStrcmp[1] + PI_BELOW_180 * along;
xlat = xlat * PI_BELOW_180;
return std::make_pair(xlat, xlong);
}
std::pair<float, float> GFSFile::cnllxy(float clat, float clon) const
{
std::pair<float, float> result;
......@@ -340,6 +388,38 @@ std::pair<float, float> GFSFile::cll2xy(float clat, float clon) const
return std::make_pair(x,y);
}
std::pair<float, float> GFSFile::cxy2ll(float x, float y) const
{
radix_tagged_line("cxy2ll(" << x
<< "," << y << ")");
float radius = EARTH_RADIUS_MEAN / 1000.f;
float xi0 = (x -mStrcmp[2]) * mStrcmp[6] / radius;
float eta0 = (y - mStrcmp[3]) * mStrcmp[6] / radius;
float xi = xi0 * mStrcmp[4] - eta0 * mStrcmp[5];
float eta = eta0 * mStrcmp[4] + xi0 * mStrcmp[5];
std::pair<float, float> ll = cnxyll(xi, eta);
radix_line("\tcnxy2ll result lat=" << ll.first
<< " lon=" << ll.second);
float xlong = cspanf(ll.second, -180.f, 180.f);
return std::make_pair(ll.first, xlong);
}
std::pair<float, float> GFSFile::cg2cll(float xlat, float xlong, float ug, float vg) const
{
float along = cspanf(xlong - mStrcmp[1], -180.f, 180.f);
float rot = - mStrcmp[0] + along;
// allow cartographic wind vector transformations everywhere
// with rotation to nominal longitudes at the poles, to match u,v values
// on a lat-lon grid
float slong = std::sin(PI_ON_180 * rot);
float clong = std::cos(PI_ON_180 * rot);
float xpolg = slong * mStrcmp[4] + clong * mStrcmp[5];
float ypolg = clong * mStrcmp[4] - slong * mStrcmp[5];
float vn = ypolg * ug + xpolg * vg;
float ue = ypolg * vg + xpolg * ug;
return std::make_pair(ue, vn);
}
std::pair<float, float> GFSFile::cg2cxy(float x, float y, float ug, float vg)
{
float xpolg = 0.f, ypolg = 0.f, temp = 0.f, xi0 = 0.f, eta0 = 0.f;
......@@ -349,10 +429,20 @@ std::pair<float, float> GFSFile::cg2cxy(float x, float y, float ug, float vg)
xpolg = mStrcmp[5] - mStrcmp[0] * xi0;
ypolg = mStrcmp[4] - mStrcmp[0] * eta0;
temp = std::sqrt( std::pow(xpolg, 2.f) + std::pow(ypolg, 2.f));
if(temp <= 1e03)
std::pair<float,float> xy;
if(temp <= 1e-3)
{
std::pair<float, float> ll = cxy2ll(x, y);
xy = cg2cll(ll.first, ll.second, ug, vg);
} else
{
// std::pair<float, float> lat_lon = cxy2ll
// use vector alegbra instread of time consuming trig
xpolg = xpolg / temp;
ypolg = ypolg / temp;
xy.first = ypolg * ug - xpolg * vg;
xy.second = ypolg * vg + xpolg * ug;
}
return xy;
}
void GFSFile::stlmbr(float tnglat, float xlong)
......@@ -574,15 +664,12 @@ std::vector<std::vector<float>> GFSFile::query(float lat
// level index starts at 0 for the surface
if(ll != lp || irec == (matchingIndex.size()-1))
{
// if(lp != 0)
// {
// if(!mHeader.latlon)
// {
// std::pair<float,float> result = cg2cxy();
// utw[lp] = result.first;
// vtw[lp] = result.second;
// }
// }
if(lp != 0 && !mHeader.latlon)
{
std::pair<float,float> xy = cg2cxy(x-1, y-1, utw[lp], vtw[lp]);
utw[lp] = xy.first;
vtw[lp] = xy.second;
}
lp = ll;
}
......@@ -599,7 +686,8 @@ std::vector<std::vector<float>> GFSFile::query(float lat
if( varb.compare("TEMP") == 0
|| varb.compare("T02M") == 0
|| varb.compare("TMPS") == 0
|| varb.compare("DP2M") == 0) vdata[kvar][ll] = vdata[kvar][ll]-273.16f;
|| varb.compare("DP2M") == 0)
vdata[kvar][ll] = vdata[kvar][ll]-273.16f;
// save the surface pressure and terrain mHeight for scaling
// of the vertical coordinate system (mHeight = signma*scaling)
......
radixio/gfsfile.hh
View file @ 52d0a190
......@@ -184,6 +184,14 @@ protected:
, float sync_lon
, float ref_lon) const;
/**
* @brief cnxyll transforms cononical (equator-centered, radian unit) coordinates
* @param xi
* @param eta
* @return std::pair<float,float> xlat, xlong
*/
std::pair<float,float> cnxyll(float xi, float eta) const;
/**
* @brief cnllxy transforms lat-lon to cononical(equator-centered,radian unit) coordinates
* @param clat real latitude
......@@ -193,8 +201,11 @@ protected:
std::pair<float,float> cnllxy(float clat, float clon) const;
std::pair<float, float> cll2xy(float clat, float clon) const;
std::pair<float, float> cxy2ll(float x, float y) const;
std::pair<float,float> cg2cxy(float x, float y, float ug, float vg);
std::pair<float, float> cg2cll(float xlat, float xlong
, float ug, float vg) const;
void stlmbr(float tnglat, float xlong);
......
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