//-------------------------------------------------------
double GribReader::computeDewPoint(double lon, double lat, time_t now)
{
double diewpoint = GRIB_NOTDEF;
GribRecord *recTempDiew = getGribRecord(GRB_DEWPOINT,LV_ABOV_GND,2,now);
if (recTempDiew != NULL)
{
// GRIB file contains diew point data
diewpoint = recTempDiew->getInterpolatedValue(lon, lat);
}
else
{
// Compute diew point with Magnus-Tetens formula
GribRecord *recTemp = getGribRecord(GRB_TEMP,LV_ABOV_GND,2,now);
GribRecord *recHumid = getGribRecord(GRB_HUMID_REL,LV_ABOV_GND,2,now);
if (recTemp && recHumid)
{
double temp = recTemp->getInterpolatedValue(lon, lat);
double humid = recHumid->getInterpolatedValue(lon, lat);
if (temp != GRIB_NOTDEF && humid != GRIB_NOTDEF)
{
double a = 17.27;
double b = 237.7;
double t = temp-273.15;
double rh = humid;
//if ( t>0 && t<60 && rh>0.01)
{
double alpha = a*t/(b+t)+log(rh/100.0);
diewpoint = b*alpha/(a-alpha);
diewpoint += 273.15;
}
}
}
}
return diewpoint;
}
//==================================================================================
// Flèches de direction du current
//==================================================================================
void GribPlot::draw_CURRENT_Arrows (
Altitude altitude,
QColor arrowsColor,
QPainter &pnt, const Projection *proj )
{
if (gribReader == NULL) {
return;
}
currentAltitude = altitude;
currentArrowColor = arrowsColor;
GribRecord *recx = gribReader->getRecord
(DataCode(GRB_CUR_VX,altitude),currentDate);
GribRecord *recy = gribReader->getRecord
(DataCode(GRB_CUR_VY,altitude),currentDate);
if (recx == NULL || recy == NULL)
return;
int i, j;
double x, y, vx, vy;
int W = proj->getW();
int H = proj->getH();
int space;
space = drawCurrentArrowsOnGrid ? currentArrowSpaceOnGrid : currentArrowSpace;
if (drawCurrentArrowsOnGrid)
{ // Flèches uniquement sur les points de la grille
int oldi=-1000, oldj=-1000;
for (int gi=0; gi<recx->getNi(); gi++)
{
x = recx->getX(gi);
y = recx->getY(0);
proj->map2screen(x,y, &i,&j);
if (true || abs(i-oldi)>=space)
{
oldi = i;
for (int gj=0; gj<recx->getNj(); gj++)
{
x = recx->getX(gi);
y = recx->getY(gj);
proj->map2screen(x,y, &i,&j);
//----------------------------------------------------------------------
if (! recx->isXInMap(x))
x += 360.0; // tour du monde ?
if (recx->isPointInMap(x,y)) {
if (true || abs(j-oldj)>=space)
{
oldj = j;
vx = recx->getInterpolatedValue(x, y, mustInterpolateValues);
vy = recy->getInterpolatedValue(x, y, mustInterpolateValues);
if (vx != GRIB_NOTDEF && vy != GRIB_NOTDEF)
{
drawCurrentArrow(pnt, i,j, vx,vy);
}
}
}
}
}
}
}
else
{ // Flèches uniformément réparties sur l'écran
for (i=0; i<W; i+=space)
{
for (j=0; j<H; j+=space)
{
proj->screen2map(i,j, &x,&y);
//----------------------------------------------------------------------
if (! recx->isXInMap(x))
x += 360.0; // tour du monde ?
if (recx->isPointInMap(x,y)) {
vx = recx->getInterpolatedValue(x, y, mustInterpolateValues);
vy = recy->getInterpolatedValue(x, y, mustInterpolateValues);
if (vx != GRIB_NOTDEF && vy != GRIB_NOTDEF)
{
drawCurrentArrow(pnt, i,j, vx,vy);
}
}
//----------------------------------------------------------------------
}
}
}
}
