Re: Streamline and streakline

Hi Yuzhong,

> I'm using VisAD to visualize some ocean data. I'd like to know whether
> VisAD has classes for streamline and streakline generation? Thank you
> very much for your help.

No, there are no classes for this.  VisAD regards streamlines
and streaklines as analyses rather than built into the display
logic.

It would be possible to write a pretty general method streamline
whose input was a wind field with MathType:

  ((x, y, z) -> (u, v, w))

and whose output was a field with MathType:

  (index -> Set(x, y, z))

where each Set has manifold dimension = 1 (i.e., a streamline
through space).  The lines could even include little arrows.
Map files are already represented as Set(x, y) with manifold
dimension = 1.  See examples/Rivers.java for a simple example.

It would be useful to check for Units in x, y, z, u, v, w
to draw accurate streamlines, and also to check for any
CoordinateSystem from (x, y, z) to reference
(Latitude, Longitude, Altitude).

For streaklines, the input Field would probably have MathType:

  (time -> ((x, y, z) -> (u, v, w)))

and the logic would be a bit more complex.

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