Hi Antonio,
> I'm newbie on visad programing, and I´m not know how to draw a contour
> plot from a set of irregular data set. I have a some meteorological
> stations in (lat,lon) format and i need to plot a contour of Maximum
> temperature.
First you should study Ugo's tutorial, linked from the
VisAD web page. For your specific problem you would do
something like this:
float[] x_locs = ... // location x coordinates
float[] y_locs = ... // location y coordinates
float[] temps = ... // temperatures at locations
RealType x = new RealType("x");
RealType y = new RealType("y");
RealType t = new RealType("t");
RealTupleType xy = new RealTupleType(x, y);
FunctionType xy_t = new FunctionType(xy, t);
float[][] locs = {x_locs, y_locs};
Irregular2DSet set = new Irregular2DSet(xy, locs);
FlatField field = new FlatField(xy_value, set);
field.setSamples(temps);
DisplayImplJ3D display = new DisplayImplJ3D("display");
display.addMap(new ScalarMap(x, Display.XAxis));
display.addMap(new ScalarMap(y, Display.YAxis));
ScalarMap cmap = new ScalarMap(t, Display.IsoContour);
display.addMap(cmap);
DataReference ref = new DataReferenceImpl("ref");
ref.setData(field);
display.addReference(ref);
// add display.getComponent() to your GUI
ContourWidget cw = new ContourWidget(cmap);
// add this to your GUI
However, VisAD currently does not support labels for contour
curves from IrregularSets. If you want labels, resample your
temperature field to a Gridded2DSet, as:
double minx = Float.MAX_VALUE;
double maxx = - minx;
double miny = minx;
double maxy = maxx;
for (int i=0; i<x_locs.length; i++) {
if (x_locs[i] < minx) minx = x_locs[i];
if (x_locs[i] > maxx) maxx = x_locs[i];
if (y_locs[i] < miny) miny = y_locs[i];
if (y_locs[i] > maxy) maxy = y_locs[i];
}
int N = 100; // or whatever resolution you like
Linear2DSet lset = new Linear2DSet(xy, miny, maxy, N, minx, maxx, N);
FlatField lfield = (FlatField)
field.resample(lset); // default is weighted average interpolation
. . .
// ref.setData(field);
ref.setData(lfield);
And please remember to study Ugo's tutorial.
Cheers,
Bill
----------------------------------------------------------
Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI 53706
hibbard@xxxxxxxxxxxxxxxxx 608-263-4427 fax: 608-263-6738
http://www.ssec.wisc.edu/~billh/vis.html
