[mapserver-users] long expression statement doesn't work anymore

Worth Lutz wal3 at mindspring.com
Fri Oct 23 11:28:48 PDT 2009


I'm seeing the same (or similar) problem.

First I query a MSsql database and get a result set.  The parcel ids from
the result set are inserted into an expression in a class which is inserted
into a layer of the map which has its geometry data in a postgres database.
(Don't ask why two databases!  We hope to move the data soon.)  The parcels
are then highlighted on the map.

The problem we are seeing is when there are lots of parcels, the resulting
map has missing parcels in the highlighted set.  My solution to this was to
reduce the number of parcels in each class to 100 and insert many identical
classes.  My results seem more stable but I still have and error when the
number of parcels exceeds 500 or so.  Each parcel id is 9 characters long
and the form of expression is "([tag] in '123456789,987654321')"



-----Original Message-----
From: mapserver-users-bounces at lists.osgeo.org
[mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Steve Lime
Sent: Wednesday, October 21, 2009 11:20 AM
To: Mapserver Mailinglist ENG; Rafael Szajbel
Subject: Re: [mapserver-users] long expression statement doesn't work
anymore

Any chance you could create a simple test case showing the problem? The fact
it shows some
features is puzzling. If it was just a matter of the expression getting
truncated then you should
see an expression parse error.

Steve

>>> Rafael Szajbel <szajbel at widemann.de> 10/21/2009 6:58 AM >>>
Hello,

in an older MapServer version (4.10.0) it is possible to use a very long
Expression or Filter statement.

Like this one with over 1000 comma separated values:

      EXPRESSION ('[NR]' IN 'ID1,ID2,.................,ID1100')

This works fine:

With newer MapServer versions (whether cgi (expression in mapfile) or
phpmapscript (expression set with setExpression)) like 5.2.1 or 5.6.0 beta3
only o small part of the polygons appears:


So is there a limit on expression statement since version 5?
There are no errors in the log-file with debug set to 5.

This is my layer definition:

  LAYER
         DATA "shapes/fs.shp"
         NAME "FS"
         STATUS ON
         TYPE POLYGON
         CLASS
              NAME "FS"
              EXPRESSION ('[NR]' IN
'ID1,ID2,.............................,ID1100')    # <-- of course without
the points ;)
              STYLE
                    COLOR 255 255 200
                    OUTLINECOLOR 0 0 0
             END
        END
  END

Thanks for any hint.

Rafael

PS: It is not possible to classify on attributes.  






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