[mapserver-users] Clustering based on a classified column

Tamas Szekeres szekerest at gmail.com
Wed Oct 19 13:04:22 EDT 2011


Hi Stephan,

I'm not sure exactly what you would like to achieve. The GROUP setting
specifies which features may belong to the same cluster. This setting can be
an expression (including the feature attributes) which evaluates to a string
value. Features with different group string value are not used within the
same cluster.

The FILTER setting can also be an expression (including the feature
attributes or the aggregated attributes) which evaluates to a boolean value.
This boolean determines whether the particular shapes should be filtered out
or not in the clustering process.

You can continue to use the CLASSITEM setting or class EXPRESSION (including
the aggregated attributes, like Cluster:FeatureCount in the expressions) to
control which class is used to display a particular clustered shape.

What do you mean by validation in the GROUP or FILTER expressions?


Best regards,

Tamas




2011/10/19 Stephan Holl <stephan.holl at intevation.de>

> Dear mapservers,
>
> I am playing arround with the CLUSTER-directive and I am going fine.
>
> Though there are some questions left I cannot answer by myself and the
> documentation.
>
> Is it possible to cluster a POINT layer based on a specific attribute
> columns? THis column is the  basis of the classification of the layer.
>
> What I want to achive is adding a label to each CLASS if the
> Cluster:FeatureCount is > 1.
>
> The docs do not make it clear for me if CLUSTER:GROUP or CLUSTER:FILTER
> is the correct stuff. Neither of them work during tests.
>
> Could someone tell me if this could be done with the CLUSTERing?
>
> And the bonus-question: if this is possible, are validation-pattern
> taken into account within GROUP or FILTER?
>
> Looking forward to your suggestions.
>
> TIA
>
> Best regards
>
>        Stephan
>
> --
> Stephan Holl <stephan.holl at intevation.de> | Tel.: +49 (0)541-33 508 3663
> Intevation GmbH, Neuer Graben 17, 49074 OS  |  AG Osnabrück - HR B 18998
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