[OpenLayers-Users] WMSGetFeatureInfo + xy mouse coordinates, can this be done?

Tue Mar 1 14:02:36 EST 2011

Several thousands is too much indeed.  You could :

   * use the BBOX strategy instead of Fixed to request for features in 
the current extent only
   * have a WMS layer on zoomed out scales and switch to WFS on zoomed 
in scales, but you wouldn't be able to interact with your WMS as you do 
with your vector features...
   * take a look at the GetFeature control and see if that could do the 
trick (currently not working, but look at the code to get the idea) :

http://dev.openlayers.org/releases/OpenLayers-2.10/examples/getfeature-wfs.html
   * setup an OGC filter to your vector layer to get only specific 
features (if your data have some kind of attribute you could filter on), 
and make only specific features display on specific zoom levels.  I 
already did something like that, see an example here : 
http://bs-dev2.mapgears.com/webmap/

Best regards,

Alexandre

On 11-03-01 01:35 PM, Andrew Stewart wrote:
> Actually I modified the strategies to be -
>
> strategies: [
>
> newOpenLayers.Strategy.Fixed(),
>
> newOpenLayers.Strategy.Cluster()
>
> ],
>
> Now I am getting the points showing up but there is still quite a 
> delay in loading / zooming etc. Is there anyway I can optimize this 
> further by limiting features etc?
>
>
> ------------------------------------------------------------------------
> *From:* openlayers-users-bounces at lists.osgeo.org 
> [mailto:openlayers-users-bounces at lists.osgeo.org] *On Behalf Of 
> *Andrew Stewart
> *Sent:* March 01, 2011 11:31 AM
> *To:* openlayers-users at lists.osgeo.org
> *Subject:* RE: [OpenLayers-Users] WMSGetFeatureInfo + xy mouse 
> coordinates, can this be done?
>
> So I am having success with point features below 100.. but is it also 
> possible to use this with many point features (several thousand?)
> My code below is trying to use the cluster strategy.. previously it 
> was Fixed but that causes my map to freeze when loading the several 
> thousand points. But when I switch to cluster nothing happens and no 
> points appear, any advice on what I'm doing wrong?
>  //Hydrant
>    var test_hydrants = new OpenLayers.Layer.Vector("Hydrant", {
>
>         strategies: [new OpenLayers.Strategy.Cluster()],
>
>         protocol: new OpenLayers.Protocol.WFS({
>             url: wfs,
>             featureType: "Hydrants",
>             featureNS: "http://www.intergraph.com/geomedia/gml",
>             featurePrefix: "gmgml",
>             srsName: "EPSG:3776",
>             //filter: filter,
>             geometryName: "Geometry",
>             version: "1.1.0"
>         })
>     });
>
>        //Add Vector Layers to Map
>        map.addLayer(test_hydrants);
>
>
> ------------------------------------------------------------------------
> *From:* openlayers-users-bounces at lists.osgeo.org 
> [mailto:openlayers-users-bounces at lists.osgeo.org] *On Behalf Of 
> *Alexandre Dube
> *Sent:* March 01, 2011 7:52 AM
> *To:* openlayers-users at lists.osgeo.org
> *Subject:* Re: [OpenLayers-Users] WMSGetFeatureInfo + xy mouse 
> coordinates, can this be done?
>
> 50~ shouldn't be a problem.  IMHO, it would be a good idea to make the 
> switch to WFS.
>
> Cheers,
>
> Alexandre
>
> On 11-03-01 09:39 AM, Andrew Stewart wrote:
>>
>> Ok thanks.. So basically if my web service does not support tolerance (which I'm pretty sure is the case) then there is not much I can do with openlayers to fix this problem.. Besides possibly changing my features into markers from my WFS and giving those markers tooltips/hotspots but not sure what the performance would be on that since I need sometimes 50+ markers.
>>
>>
>> -----Original Message-----
>> From:openlayers-users-bounces at lists.osgeo.org  [mailto:openlayers-users-bounces at lists.osgeo.org] On Behalf Of Alexandre Dube
>> Sent: March 01, 2011 6:49 AM
>> To:openlayers-users at lists.osgeo.org
>> Subject: Re: [OpenLayers-Users] WMSGetFeatureInfo + xy mouse coordinates, can this be done?
>>
>> Hi,
>>
>> That could be setup in your web mapping service. If you use MapServer,
>> you could set the Layer object definition "TOLERANCE" parameter for that.
>>
>> Regards,
>>
>> Alexandre
>>
>> [1]http://mapserver.org/mapfile/layer.html  (search for "TOLERANCE")
>>
>>
>> On 11-02-28 10:02 PM, Planet)x wrote:
>>> I have a slight problem which has to do with my WMS mainly but wondering if
>>> there is a way to program around it. Well problem is I can increase the
>>> symbol size for points on my Web service but the geometry of the point
>>> (centroid) remains the same. Therefore when using a
>>> OpenLayers.Control.WMSGetFeatureInfo the feature info is never returned
>>> until I move the mouse directly in the middle of the point feature (and also
>>> lines unfortunately). Question is can I somehow force the mouse to be moved
>>> to the center of the point when it nears a symbol.. and is there anyway to
>>> actually get the entire coordinates for the symbol so I can use them to do
>>> the featureinfo somehow? Not sure if this makes sense or if there is another
>>> approach I can utilize to do this.. appreciate any advice!
>>>
>>
>>
>> _______________________________________________
>> Users mailing list
>> Users at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/openlayers-users
>
>
> -- 
> Alexandre Dubé
> Mapgears
> www.mapgears.com
>
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-- 
Alexandre Dubé
Mapgears
www.mapgears.com

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