[mapserver-users] PostGIS performance

[Alexander Pucher]

Hallo Jan,

Jan Hartmann wrote:

> Alexander Pucher wrote:
>
>> I think the problem is in the use of the EXPRESSION with a PostGIS 
>> layer. In the documentation I found a line, saying that CLASSITEM is 
>> not used in a PostGIS layer. One has to use the field name in the 
>> EXPRESSION tag!!
>>
>
> Where did you read that??? Anyway, it's not true. 

On page 64 of the 'UMN MapServer Handbuch und Referenz', published by 
MapMedia and mentioned several times on this group, the chapter on 
PostGIS says :

"...folgen wieder die einzelnen Klassen zur Definition der Darstellung. 
Falls Sie an dieser Stelle EXPRESSIONs benutzen mo"chten, beachten Sie 
bitte, dass Sie hier Feldnamen explizit angeben mu"ssen, da es kein 
CLASSITEM in einem PostGIS-Layer gibt."

Please excuse if I misinterpreted this.

> [...]

Thanks for the file, I think my problem sits deaper. I will check my 
whole MapServer Installation once again and see what I can do. Maybe I 
try the Nightly Build.

> To be noted:
>
> 1) You can use both an EXPRESSION from a CLASSITEM and a logical 
> EXPRESSION.
> 2) You can use both an original variable and a computed one, provided 
> you have named them in the subselect.
> 3) In literal EXPRESSIONS numeric variables have to be quoted or 
> constructed as regex.
> 4) In logical EXPRESSIONS you can use numeric variables as numeric or 
> as strings.

Thanks for that!

Regards,
alex


-- 
________________________________________________________

Institut fuer Geographie und Regionalforschung
Universitaet Wien
Kartografie und Geoinformation

Departement of Geography and Regional Research
University of Vienna
Cartography and GIS

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Tel: (+43 1) 4277 48644
Fax: (+43 1) 4277 48649
E-mail: alexander.pucher at univie.ac.at

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