Using data depictions to select a region...

Hi, I am new at this VisAd staff, the only thing I can tell by now is that
it looks great.
I am trying (unsuccessfully) to put some code into de VisAd Spreadsheet so I
can use a couple depiction points to select a region. Could you please give
an idea (or example) of how to do that.
Forgive my English please.
Thanks.




              pol
      pol@xxxxxxxxxxxxxxx
http://www.chasque.apc.org/pol
    Facultad de Ingeniería
     Montevideo - URUGUAY