Hi Stuart,
> Again working through Ugo Taddei's VisAd tutorial, in section 3.5
> (http://www.ssec.wisc.edu/~billh/tutorial/s3/Section3.html)
>
> I am trying to modify the example program P3_05 to plot contours
> of one color on a color-filled background map of the same quantity.
>
> The program as given plots contours of temperature, and the contours
> are colored according to the underlying elevation. I want to have one color
> contours of temperature over a background colored by temperature value.
>
> Commenting out the "display.addMap( elevMap );"
> I get white contours on a black background, which is fine.
>
> then using (in place of tempIsoMap),
> tempMapRGB = new ScalarMap( temperature, Display.RGB );
> display.addMap( tempMapRGB );
>
> I get a colored field, colored according to temperature values. As expected.
>
> So I think I shall plot white contours over the colored temperature
> field, by using both tempIsoMap and tempMapRGB. To my surprise
> I get colored contours, and no colored field at all. Why?
>
> Why does adding a isocontour map means my surface gets
> destroyed, when I simply wanted to have the isolines on top of the
> surface?
The behavior of the default DataRenderers is to render either
contours or filled colors for a single FlatField (instead of
contours, you could also substitute flow vectors, shapes or
text).
To do what you want with the default DataRenderers is a little
tricky. You need to make a copy of 'FlatField vals_ff'
temperature values with a new RealType substituted for
temperature in its MathType (which is a FunctionType).
Something like this:
. . .
temperature_2 = new RealType("temperature_2");
func_domain_range_2 = new FunctionType( domain_tuple, temperature_2);
. . .
vals_ff = . . .
float[][] values = vals_ff.getFloats(false); // don't copy
float[][] values_2 = {values[0]};
FlatField vals_ff_2 = new FlatField(func_domain_range_2, domain_set);
vals_ff_2.setSamples(values_2, false); // don't copy
. . .
// simple color fill with temperature_2 values
display.addMap(temperature_2, Display.RGB);
. . .
DataReferenceImpl data_ref_2 = new DataReferenceImpl("data_ref_2");
data_ref_2.setData( vals_ff_2 );
display.addReference(data_ref_2);
. . .
Leave all the other logic alone, to get the iso-contours of
temperature values in vals_ff. I have not tried this code,
but the basic idea should work.
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
