This works for me.
Try this:
Create two layers with the same name and group.
Layer 1 ( takes care of values 2000 and 2100) :
LAYER
NAME "A"
GROUP "A"
.....
PROCESSING 'NATIVE_FILTER=gst IS NOT NULL'
CLASS for 2000
....
CLASS for 2100
....
END
Layer 2 ( value = NULL ) ❤️
LAYER
NAME "A"
GROUP "A"
....
PROCESSING 'NATIVE_FILTER=gst IS NULL'
CLASS for NULL
....
END
________________________________
Från: MapServer-users <mapserver-users-boun...@lists.osgeo.org> för Seth G via
MapServer-users <mapserver-users@lists.osgeo.org>
Skickat: den 28 mars 2025 10:43
Till: angelique.kro...@stadt-koeln.de <angelique.kro...@stadt-koeln.de>;
MapServer Users <mapserver-users@lists.osgeo.org>
Ämne: Re: [MapServer-users] NULL-EXPRESSION
Hi,
Unfortunately, MapServer doesn't have a NULL type.
The workaround is to create a database view or query that will set the NULL to
a numeric value of your choosing, e.g. -1 and then use that value in the CLASS
expressions.
Seth
--
web:https://geographika.net & https://mapserverstudio.net
mastodon: @geographika@mastodon.social<mailto:geographika@mastodon.social>
On Fri, Mar 28, 2025, at 8:55 AM, Angelique Kroisl via MapServer-users wrote:
Hello,
I'm trying to create a class using the class item "gst."
The attribute in the database can only have three values (2000, 2100, and
<NULL>).
Unfortunately, I can't create the NULL EXPRESSION.
I've already tried the following:
EXPRESSION IS NULL
EXPRESSION "<NULL>"
EXPRESSION <NULL>
EXPRESSION EMPTY
What is the correct syntax for this?
________________________________
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