Hy,
I just had the same idea as you, Stephan, to cluster features based on
attribute values. I think your expression fails because "1" != 1, so
basically you can't do maths (<>) with the Cluster:FeatureCount, just
String comparisons.
Actually I don't understand the reason why that is so. Imo
ClusterFeatureCount should return a number, not a String.
Frank
Am 20.10.2011 10:36, schrieb Stephan Holl:
Hello Tamas,
thanks for you reply.
Tamas Szekeres<szeker...@gmail.com>, [20111019 - 19:04:22]
I'm not sure exactly what you would like to achieve.
Sorry, let my show an example to make it clear:
I have a classified layer based on the following CLASSES
CLASS
NAME "bar"
EXPRESSION ('[typ]'='bar')
STYLE
SYMBOL "bar"
END
END
CLASS
NAME "foo"
EXPRESSION ('[typ]'='foo')
STYLE
SYMBOL "foo"
END
END
... more CLASSes
As you see, they are classified by the values of the column [typ].
What I want to achieve is adding a label (with the
Cluster:FeatureCount as text) if the different classes have more
identical attributes within the MAXDISTANCE.
What I currently do is adding another CLASS:
LABELITEM "Cluster:FeatureCount"
CLASS
NAME "Clustered foo"
EXPRESSION ("[Cluster:FeatureCount]"> "1"&& '[typ]'='foo')
STYLE
SYMBOL "foo"
END
STYLE
SIZE 20
OFFSET 15 15
SYMBOL "circle"
COLOR 255 0 0
END
LABEL
FONT freesans
TYPE TRUETYPE
SIZE 10
COLOR 255 255 255
OFFSET 15 15
ALIGN CENTER
PRIORITY 10
BUFFER 1
PARTIALS TRUE
POSITION cc
END
END
CLASS
NAME "foo"
EXPRESSION ('[typ]'='foo')
STYLE
SYMBOL "foo"
END
END
... more CLASSes
The problem of the above is, that I have to include the SYMBOL 'foo'
also in the clustered CLASS, because the normal SYMBOL does not show up
(because it is not there since it is clustered now...).
But: I have to do that for all classes I have currently (about 25).
My thinking was about a dynamic classification and clustering based on
the attributes of a specific column ([typ]), but I cannot make it work.
Does this make more sense to you now?
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.
Thanks for your clarification, this is helpful for my understanding.
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?
Does my above example more sense to you?
Best
Stephan
2011/10/19 Stephan Holl<stephan.h...@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
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