[Geoprisma-dev] QueryOnClick - Highlighting WFS.fromWMSLayer

[Alexandre Dube]

Hey,

Yves Moisan wrote:
> New thread = "Highlighting WFS.fromWMSLayer" 
>   

New thread should be new message too, I think...

>
> Right.  Here's what's in /OpenLayers/Protocol/WFS.js :
>
> "Function: OpenLayers.Protocol.WFS.fromWMSLayer 
>
> Convenience function to create a WFS protocol from a WMS layer. This
> makes the assumption that a WFS requests can be issued at the same URL
> as WMS requests and that a WFS featureType exists with the same name as
> the WMS layer."
>
> If we take the service url, maybe the proxy could issue a WFS request to
> the <wms> service url (e.g. MapServer in our case) and get something
> back without the need to add another resource ?  I just thought the very
> name "WFS.fromWMSLayer" was a hint that one could get some features from
> a WMS layer.  I know better how that works now.  
>   

Still, the query sent must go thought the proxy, so a new "WFS" service 
would be required, so it would be needed in the config file anyway...

I think we could accomplish the same with FeatureServer since the same 
logic from "fromWMSLayer" is already existant in GeoPrisma with our 
multiple DataStores in Resources concept.

> Highlighting a feature after either a query for info (QueryOnClick) or
> when one ends up zoomed on a feature (ShortCut, InitialView, the
> deprecated QuickZoom) is really one of the most obvious things missing
> in the eyes of GeoPrisma users so I figured if someone got a feature
> highlighting to work on a WMS layer, that would be worth investigating.
>
> In short, can we get a small number of features (e.g. those
> corresponding to the tolerance set e.g. in the mapfile) that could be
> used on a "highlight" utility layer that could be used for other things
> as a "temp" layer in GeoPrisma much like for example the "Cosmetic
> layer" (or whatever its name) is used in MapInfo to store transient
> features/annotations, etc. ?
>
>   

I would still work with the existing vector layer that uses the same 
data.  If it's not there, then we should find a way to interact with 
what we have.

Or, even better, let's compare with Google Maps.  When searching for 
"Racine street, Chicoutimi, QC, Canada", it recenters the map on the 
street without changing the color (makes sens, it's a cached layer) and 
a simple marker is added.  Simple enough in my opinion.  The minimum 
should be to have all layers turned to on (displaying the features if 
it's a vector layer else showing an image) with the Shortcut widget 
(already the case) and the InitialView, no more.

Query widgets don't move the map, but a marker is still added.  Having 
the possibility to click on a result to zoom to the queried feature is 
something else (there's already a jira ticket for this and also a 
OpenLayers enhancement ticket too)....

Should the query zoom to the extent of all results found too ?  That 
could be something cool to have as a new option (like the shortcut)...

What do you think ?

> Yves
>
>
>   


-- 
Alexandre Dubé
Mapgears
www.mapgears.com