Class with join

[Erich Schroeder]

Hi,
  I'm hoping that I can do this without mapscript. I have a point coverage
with site locations. Each site can have multiple animal taxa and time
periods associated. I therefore have a sites.dbf file with the following
fields:

    1 AREA        N     12   3
    2 PERIMETER   N     12   3
    3 SITES_      N     11   0
    4 SITES_ID    N     11   0
    5 COUNTRY     C      3   0

and a file with all the taxa and time records with the following fields:

    1 SITES_ID    N      5   0
    2 TAXON       C      6   0
    3 AGE         C      4   0
    4 RESTAXON    C      6   0
    5 RIO         C      3   0

I want to be able to make a map file which will just show sites with a
particular taxon, and ultimately just that taxon from a particular age. 

I tried this:

LAYER
  NAME sites
  TYPE POINT
  STATUS DEFAULT
  DATA sites
  CLASS
    SYMBOL 4
    COLOR 255 0 0
    NAME "BIbi Sites"
    EXPRESSION ([TAXON] = "BIbi")
    JOIN
       table "alltaxa.dbf"
       type single
       from "SITES_ID"
       to "SITES_ID"
    END # join
  END
END

But this doesn't work as Joins are to be used in queries, as I understand.
I'm sure that what I want to do is possible, but I don't know how.

eks

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Erich Schroeder                    Phone: (217)785-0033
Curator, Information Technologies  FAX:   (217)785-2857
Illinois State Museum GIS Lab      Internet: erich at museum.state.il.us
http://www.museum.state.il.us/
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