[mapserver-users] Vectorizing/digitizing points that have been rendered as raster

[Rahkonen Jukka]

Hi,

Mapserver 6.0 is listing these filter capabilities
<ogc:Equals/>
<ogc:Disjoint/>
<ogc:Touches/>
<ogc:Within/>
<ogc:Overlaps/>
<ogc:Crosses/>
<ogc:Intersect/>
<ogc:Contains/>
<ogc:DWithin/>
<ogc:BBOX/>

I am not totally sure that all of them really works.  Now it depends a bit about your need what filter to use.  DWithin from the point should give exact results but probably you would need to adjust the distance according to the map scale.  BBOX might be faster but then you must make a rectangle around the clicked point.

About the same result can be obtained also with WMS GetFeatureInfo. Configure a suitable outputformat (text/plain, text/html or gml), use big enough feature_count and reasonable pixel based tolerance in the mapfile.

-Jukka Rahkonen-


Wim Vanbelle  wrote
Hi,

Currently we have a lot of big datasets with points (think 50k points for instance) that we can now cluster service side with mapserver (cool).
That works like a charm, but now we would like to fetch information if you click on them. (be it a clustered icon, or a non clustered).

The client we are using is google maps with custom javascript code.

As far as I'm aware, I need to perform a WFS request for this. I haven't got any problems setting that up, but what should be passed as a filter?

Can we just pass a point as a filter in the request, or are we forced to supply a bounding box. I'm wondering if there are common solutions to tackle a similar problem.

Thanks in advance.

Best regards.
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