Re: drawing arrows

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wanted to let you know that I used the suggestion of a UnionSet of 
Gridded2Dsets (following roughly the river example) and it was just what I 
needed. I also grabbed Leah's math for drawing arrowheads, which saved me 
some time :-)

thanks!
Donna

Donna L. Gresh, Ph.D.
Optimization and Mathematical Software Group
IBM T.J. Watson Research Center
(914) 945-2472
http://www.research.ibm.com/people/g/donnagresh
gresh@xxxxxxxxxx





Bill Hibbard <billh@xxxxxxxxxxxxx>
Sent by: owner-visad-list@xxxxxxxxxxxxx
08/07/2003 05:09 PM
 
        To:     Donna L Gresh/Watson/IBM@IBMUS
        cc:     visad-list@xxxxxxxxxxxxx
        Subject:        Re: drawing arrows


Hi Donna,

With your ScalarMaps of u to Flow1X and v to Flow1Y, try
experimenting with calls to the setScale() method of the
FlowControl. See visad/examples/Test28.java for an example.

You can also draw a bunch of lines between points as a
UnionSet of Gridded2DSets with manifold dimension = 1.
See visad/examples/Rivers.java for an example.

Good luck,
Bill

On Thu, 7 Aug 2003, Donna L Gresh wrote:

> Is there a simple way to simply draw a set of arrows from one set of
> points to another? (my desire is to show the displacement of a set of
> points)
>
> I have set up a FlatField mapping (x,y) ->(u,v), where the (u,v)'s I've
> computed as the difference between x1,y1 and x2,y2. Thus I'd like to 
draw
> lines starting at points x,y with length u,v.
>
> I've tried constructing a scalarmap of u to Flow1X and v to Flow1Y, but
> nothing seems to appear in the display. It may well be that I'm still 
not
> doing things exactly as they should be, but is this the right approach?
>
>
>
> Donna L. Gresh, Ph.D.
> Optimization and Mathematical Software Group
> IBM T.J. Watson Research Center
> (914) 945-2472
> http://www.research.ibm.com/people/g/donnagresh
> gresh@xxxxxxxxxx
>



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