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
_______________________________________________
mapserver-users mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/mapserver-users
