[mapserver-users] Querymap display via WMS interface?

[Daniel Morissette]

Tom is correct that at this point GetFeatureInfo can return only GML,
HTML or plain text.  

But since the querymap feature is already there and available in
MapServer, one thing we could do with the WMS interface is that if a
QUERYMAP is defined in the mapfile then we include image types as
additional GetFeatureInfo formats in the capabilities... and then if
someone sends a GetFeatureInfo request with INFO_FORMAT=image/png for
instance then they would receive the querymap in PNG format with the
selected objects highlighted.

I've filed this in bugzilla as a potential enhancement for MapServer 3.7
(http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=191)

Daniel



"Kralidis, Tom" wrote:
> 
> > -----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.
> 
> ..Tom
> 
> =================================
> Tom Kralidis
> Systems Scientist
> Canada Centre for Remote Sensing
> Tel: (613) 947-1828
> http://www.ccrs.nrcan.gc.ca/
> =================================