[mapserver-dev] testing CLUSTER object

[Tamas Szekeres]

2011/4/14 Jeff McKenna <jmckenna at gatewaygeomatics.com>

> - why isn't the LAYER TYPE ANNOTATION supported for the cluster object?  A
> common trick for labelling symbols is to use an annotation layer, I really
> think the cluster logic should be applied to that type as well.
>
>
Hi Jeff,

We have no specific reason not to support the annotation layers since those
are point layers in most cases. I will see how it could be enabled too.



> - I think there is a problem with query results from a cluster.  If I query
> a non-cluster-object group of features with mode=nquery (and a template set
> at the LAYER level) I get the correct number of features returned; If I
> query the same cluster-object group of features with mode=nquery (and a
> template set at the LAYER level) I only ever get one feature result (testing
> with MapServer trunk).  Thoughts?
>
>
I'm not sure what you mean by querying a  non-cluster-object group or
querying the same cluster-object group. With the current approach we can
query only those features which are actually generated (displayed) for that
layer (ie the clustered features) and there's no such mechanism to retrieve
the features behind a cluster (if I understand the question correctly). This
option would require the driver to behave differently regarding to the query
and the normal drawing operations.



> - If you look at my example layer (
> http://www.mapserver.org/trunk/mapfile/cluster.html#example-clustering-railway-stations),
> you can see that I had to do some tricks with an expression to not show a
> cluster object for when the featurecount = 1; should this be the case?
>  Would anyone using MapServer ever need a cluster for one feature?
>
>
Good question, I thought if that can be filtered by using the filter
expression of the cluster object.



> - I've had "challenges" trying to stop the cluster circle symbols from
> being split at tile edges with mod-geocache (
> http://labs.gatewaygeomatics.com/cluster/demo.html) Yes it could be a
> missing setting either in my mapfile or in my geocache.xml, but I still want
> to report this.  Maybe this is a good sign that we (MapServer or
> mod-geocache) need to make it easier for new users to prevent this from
> occurring?
>
>
Is this dedicated to the cluster layer as a problem?

Thanks for testing this, your comments and document additions were really
helpful.

Best regards,

Tamas
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