Re: streamlines

Hi Doug,

> Given a wind field, I'd like to display streamlines. Has anyone done
> this with VisAD?

There are two approaches to streamlines in VisAD.  One is
to create a custom DataRenderer that analyzes and renders
streamlines for RealTypes mapped to Display.Flow* (and also
checks the MathType of the Data being rendered to ensure
that streamlines makes sense - i.e., a Field over a 2 or
3 dimensional domain).

The other approach is to write a subclass of CellImpl whose
input is a FlatField with MathType such as ((x, y) -> (u, v))
and whose output is a UnionSet of Gridded2DSets with manifold
dimension 1.  That is, a collection of lines just like are
used for maps, except in this case they would draw streamlines.

If you've got some streamline code lying around, it wouldn't
be to difficult to produce such a CellImpl subclass.  If you
do write such a subclass, we'd love to distribute it as part
of VisAD.

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