SV: [mapserver-users] Classitems selection
Fawcett, David
David.Fawcett at state.mn.us
Thu Aug 13 07:07:46 PDT 2009
Christy is right.
With a reasonably small number of items, either the IN syntax or the regular expression will work.
I use the IN syntax to classify 87 counties in an app and it runs fast. A recent comparison done by Adrian Popa indicates that the regular expression syntax is faster.
Here is the thread: http://lists.osgeo.org/pipermail/mapserver-users/2009-July/062071.html
David.
-----Original Message-----
From: mapserver-users-bounces at lists.osgeo.org [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Christy Nieman
Sent: Thursday, August 13, 2009 9:01 AM
To: Lars Westerlind
Cc: mapserver-users at lists.osgeo.org
Subject: Re: SV: [mapserver-users] Classitems selection
Hi,
When you say that you could very well use expressions, do you mean
regular expressions? In my experience, unless you are working with a
very large data set they're fine.
E.g.
CLASSITEM "flavour"
...
EXPRESSION /cherry|mango|lime/
Christy
Lars Westerlind wrote:
>
> AFAIK currently I write
>
> CLASSITEM "flavor"
>
> ...
>
> EXPRESSION "cherry"
>
> Suggested extension would be to allow for
>
> CLASSITEM
>
> ...
>
> EXPRESSION "cherry","mango","lime"
>
> But really, syntax is not my concern. A could very well use
> expressions, but the documentation says they are not good for
> performance. And my first question is if I've missed something?
>
> ----------------------------------------------------------------------
> --
>
> *Från:* Fawcett, David [mailto:David.Fawcett at state.mn.us]
> *Skickat:* 13 August 2009 15:39
> *Till:* Lars Westerlind; mapserver-users at lists.osgeo.org
> *Ämne:* RE: [mapserver-users] Classitems selection
>
> Do you mean something like ('[flavor]' IN ('cherry', 'mango', 'lime')?
>
> -----Original Message-----
> *From:* mapserver-users-bounces at lists.osgeo.org
> [mailto:mapserver-users-bounces at lists.osgeo.org] *On Behalf Of
> *Lars Westerlind
> *Sent:* Thursday, August 13, 2009 2:39 AM
> *To:* mapserver-users at lists.osgeo.org
> *Subject:* [mapserver-users] Classitems selection
>
> I use the CLASSITEM - EXPRESSION with string expression rather
> much, which is also recommended for performance. But sometimes I
> have a few values that could be shown in the same class. Wouldn't
> it be a nice idea to allow for a commaseparated set/list of
> strings to match?
>
> ----------------------------------------------------------------------
> --
>
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> mapserver-users at lists.osgeo.org
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