Hi Yuzhong,
> I have a binary file containing 2-D scalar data in raw format, I'd like
> to know how to read the file. Is there a class in VisAD that can read
> such raw file directly, or do I have to write codes in Java to read the
> file by myself? Thanks a lot.
VisAD has file readers for a variety of specific formats
(e.g., netCDF, HDF-5, McIDAS, GIF, etc) but for a new format
you'll need to write some code to read the file and build
a VisAD data object. 2-D scalar data shouldn't be too
difficult. For example, if you read your data into an
array named "data" of size "float[nx][ny]" then you'd
construct a VisAD Data object like this:
RealType x = new RealType("x");
RealType y = new RealType("y");
RealType scalar = new RealType("scalar");
RealTupleType domain = new RealTupleType(new Real[] {x, y});
FunctionType function_type = new FunctionType(domain, scalar);
Integer2DSet domain_set = new Integer2DSet(nx, ny);
FlatField field = new FlatField(function_type, domain_set);
float[][] field_data = new float[1][nx * ny];
int k = 0;
for (int j=0; j<ny; j++) {
for (int i=0; i<nx; i++) {
field_data[0][k] = data[i][j];
k++;
}
}
field.setSamples(field_data);
Then you can visualize the "field" data object with
something like this:
DisplayImplJ3D display = new DisplayImplJ3D("scalar display");
display.addMap(new ScalarMap(x, Display.XAxis));
display.addMap(new ScalarMap(y, Display.YAxis));
display.addMap(new ScalarMap(scalar, Display.ZAxis));
DataReference ref = new DataReferenceImpl("scalar data");
ref.setData(field);
display.addReference(ref);
Which should make a simple terrain surface. Lots of other
possibilities exist.
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
