[mapserver-users] Querymap display via WMS interface?
Tom.Kralidis at ccrs.nrcan.gc.ca
Sun Aug 25 22:30:47 EDT 2002
> -----Original Message-----
> From: Neel Smith [mailto:neelsmith at yahoo.com]
> Sent: Sunday, August 25, 2002 9:27 PM
> To: mapserver-users at lists.gis.umn.edu
> Subject: [mapserver-users] Querymap display via WMS interface?
> I've recently created a mapserver client as part of a
> larger web application implemented with Cocoon. The
> client communicates with mapserver exclusively through
> WMS protocols (a requirement for this particular app.)
> For navigational interaction (pan/zoom), mapserver's
> graphic output is great; for queries by clicking, the
> data results are great (getting output in GML is
> wonderful!) -- but I haven't been able to figure out
> how to get graphic output illustrating query results.
> I'd like for selected features to be highlighted.
> I know that mapserver can do this but I can't seem to
> find anyplace in the WMS protocol where this
> functionality might be exposed. (STYLEs?)
> Can anyone point me in the right direction? Is it
> possible to get the equivalent of mapserver's querymap
> output using only the OGIS WMS interface?
Not per se. Querying WMS usually involves GML.1, GML.2, plain text or HTML
at this point.
The Styled Layer Descriptor (SLD) Specification can help here. SLD is an
OGC technology which allows a client to, along with a WMS request, pass the
URL of an XML document describing how to style requested layers. SLD
documents can contain multiple rulesets with flexible criteria such as scale
and filter expressions.
When MapServer supports SLD, one will be able to send filters and styling
rules in real-time to receive custom maps from an SLD-enabled WMS. Until
then, one can have some middleware which styles XML into an output image.
Hope this helps.
Canada Centre for Remote Sensing
Tel: (613) 947-1828
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