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Re: use netcdf data and draw with visad problem..

Hello,

I can't offer you any advice about how to get your code working, but I
can offer you a suggestion. You might want to take a look at the
Integrated Data Viewer from Unidata. It's a high-level framework (based
partly on visad) for looking at geo-science data. First of all you might
find that it creates the plots you need with no coding on your part. If
you find that you need to write code to achieve your goals, you can take
advantage of the IDV source code and existing classes for some good
examples.

Roland

劉育帆 wrote:
> Dear All:
> I have a netcdf file which have head file like this, and
> I want to get the data (rhum[0][1][][]) to draw with visad ...
> I don't know how to assign the section netcdf data to draw with visad.
> Is there any function I can use or any example which about get nectdf
> file,
> parse it and draw with visad..thanks a lot(special get section data)
>
> netcdf rh {
> dimensions:
> time = 10 ;
> level = 8 ;
> lat = 73 ;
> lon = 144 ;
> variables:
> short rhum(time, level, lat, lon) ;//rhum[time][level][lat][lon]
> .....
> .....
> rhum:add_offset = 302.65f ;
> rhum:scale_factor = 0.01f ;
> .....
> .....
> }
>
>
>
> [code]
> import visad.data.netcdf.*;
>
> Field imagesNC = null;
> DisplayImpl display = new DisplayImplJ3D("image display");
>
> try
> {
> imagesNC = (Field) plain.open("C:/tempNcfile/rh.nc");
> }
> catch (IOException exc)
> {
> System.out.println(exc);
> System.exit(0);
> }
>
> final Field image_sequence = imagesNC;
> FunctionType image_sequence_type = (FunctionType)
> image_sequence.getType();
> FunctionType image_type = (FunctionType) image_sequence_type.getRange();
> RealTupleType domain_type = image_type.getDomain();
>
> // map image coordinates to display coordinates
> display.addMap(new ScalarMap((RealType) domain_type.getComponent(0),
> Display.XAxis));
> display.addMap(new ScalarMap((RealType) domain_type.getComponent(1),
> Display.YAxis));
> display.addMap(new ScalarMap((RealType) domain_type.getComponent(2),
> Display.ZAxis));
>
> // map netcdf variable(varname) values to RGB
> RealTupleType range_type = (RealTupleType)image_type.getFlatRange();
> for(int nIdex = 0 ; nIdex < range_type.getNumberOfRealComponents() ;
> nIdex++)
> {
> String netcdf_varname = range_type.getComponent(nIdex).prettyString();
> if(netcdf_varname.equals(varname))
> {
> display.addMap(new ScalarMap((RealType)
> range_type.getComponent(nIdex), Display.RGB));
> break;
> }
> }
>
> // link the Display to image_ref
> // display will update whenever image changes
> final DataReference image_ref = new DataReferenceImpl("image");
>
> image_ref.setData(image_sequence);
> display.addReference(image_ref);
> [/code]
>
> Can I use "import visad.data.netcdf.*;" functions in these package, or
> rewrite parse function in netcdf class package?
>
> Please Help me, thank you~~ :)
>
> p.s I have other question with this..Any boby knows what's wrong ?
> why I run examples.VerySimple class which input val(x, y) netcdf file
> will be ok, but
> I run same function which input rhum(time, level, lat, lon) will get
> these exception..
>
> visad.BadMappingException: DisplayImpl.addMap: DisplayZAxis illegal
> for this DisplayRenderer
> at visad.DisplayImpl.addMap(DisplayImpl.java:1884)
> at visad.DisplayImpl.addMap(DisplayImpl.java:1846)
> at visad.util.DataUtility.makeSimpleDisplay(DataUtility.java:329)
> at examples.VerySimple.main(VerySimple.java:45)
>
> Thanks a lot :)