[mapserver-users] getFeatureInfo() Only Works on One Layer?

[Bill Thoen]

Well, when I moved the application to a publicly-accessible server to 
show you all, it worked as it should. Turns out my server has the latest 
version of MapServer installed, but my workstation is running an older 
one, and so I guess the problem got fixed in the newer release. 



Yewondwossen Assefa wrote:
> Bill,
>
> You might try setting the layers in the QUERY_LAYERS parameter without 
> any space: QUERY_LAYERS: "us_interstate,us_states".
> If that does not work, as suggested you might give the full URL sent 
> to Mapserver.  From what I can see, query on more that one layer is 
> possible  (URL using the Mapserver5.2.1 : 
> http://www2.dmsolutions.ca/cgi-bin/mswms_gmap?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetFeatureInfo&BBOX=-173.433000,36.354100,-12.969800,83.746600&SRS=EPSG:4326&WIDTH=785&HEIGHT=232&LAYERS=park%2Cpopplace&STYLES=%2C&FORMAT=image/png&TRANSPARENT=TRUE&QUERY_LAYERS=popplace,park&INFO_FORMAT=text/plain&X=302&Y=121&feature_count=1 
>
>
> Best Regards.
>
>
> Bill Thoen wrote:
>> I originally asked this on the OpenLayers forum, but was told that 
>> this is really a Maperver question. So I'll try it here.
>>
>> I've got a WMS layer that has two sub-layers in it and I'm trying to 
>> get attribute information from them via a getFeatureInfo request, but 
>> I can only get one of them to respond at a time. I've looked at the 
>> docs at  http://trac.openlayers.org/wiki/GetFeatureInfo and noticed 
>> that you can specify several layers with the QUERY_LAYERS parameter, 
>> but I'm finding that only the one listed first is active. Also, it's 
>> not clear what layer you specify at the root of the request, but it 
>> looks like it's supposed to be different from the layers you're 
>> querying. Anyway, here's what I'm trying:
>>
>> I open and load the combined layer like so:
>> base = new OpenLayers.Layer.WMS(
>>   "Base",
>>   "http://192.168.0.250/cgi-bin/mapserv?map=base.map",
>>   { layers: ["us_states", "us_interstate"] }
>> );
>> map.addLayer(base);
>>
>>
>> And here's the request string I'm sending to MapServer:
>>
>> var url = base.getFullRequestString({
>> REQUEST: "GetFeatureInfo",
>> EXCEPTIONS: "application/vnd.ogc.se_xml",
>> FORMAT: 'png',
>> BBOX: map.getExtent().toBBOX(),
>> X: event.xy.x,
>> Y: event.xy.y,
>> INFO_FORMAT: 'text/plain',
>> QUERY_LAYERS: "us_interstate, us_states",
>> FEATURE_COUNT: 1,
>> WIDTH: map.size.w,
>> HEIGHT: map.size.h},
>> "http://192.168.0.250/cgi-bin/mapserv?map=base.map&");
>> OpenLayers.loadURL(url, '', this, setHTML);
>>
>> Note the QUERY_LAYERS line. As shown here, it responds with 
>> interstate attributes only when I click on an interstate roadway 
>> feature, but I get nothing when I click on a state. If I reverse the 
>> order of these layers in the list, then clicking on a state returns 
>> attributes from the us_states table only. Even if I click on a spot 
>> where features in both layers coincide, it returns only the 
>> attributes for the layer listed first.
>>
>> Also, setting the FEATURE_COUNT parameter to something higher than 1 
>> just
>> gives me more results from the single that  is working.
>>
>> So how do I use multiple layers in the QUERY_LAYERS parameter, or do 
>> I get only one at a time? Also, I just guessed at using the layer 
>> called 'base' for the getFeatureInfo oject, what is supposed to be 
>> used here?
>>
>> TIA,
>> - Bill Thoen
>>
>>
>>
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>>
>
>