[OpenLayers-Users] wfs feature geometry based on one attribute value

[Lehtonen, Mika]

Alexandre Dube kirjoitti:
>>
>>
>> I have my data in PostGIS and I mean features that aren't shown in my 
>> map. Or actually they are shown, but through wms. I am already 
>> fetching some attributes after geometry comparison through wfs 
>> GetFeature, but I was wondering whether there would some other ways 
>> to do that.
>
> Could you share an example of this ?  I would like to see how you do it.
>
> Alexandre
Sure,
it ain't no rocket science. I'm using GeoServer and PostGIS. I have 
about 3000 polygons in my wfs service and I need to get some attributes 
out of those I choose using wms-layer as a reference. The choosing tool 
is sort of a buffer tool (choose all features which are entirely or 
partially inside the circle). First I do the GetFeature.( I'll try to 
incorporate only the essential parts..)

function buffer(e) {      
                var url =  wfs.getFullRequestString({
                SERVICE: 'WFS',
                VERSION: '1.0.0',
                REQUEST: 'GetFeature',
                OUTPUTFORMAT: 'json',
                PROPERTYNAME: 'the_geom,attr1',
                MAXFEATURES: 1000,
                TYPENAME: 'ns:layername',
                SRSNAME: 'EPSG:900913',
                CQL_FILTER: 'INTERSECT(the_geom,'+ buffergeometry +')'
                },
                           "http://host.domain/geoserver/wfs"
                            );
                OpenLayers.loadURL(url,'',this,bufferUpdate);   
                Event.stop(e);
                };

Then I dig the attributes I need out of the response:

function bufferUpdate (response) {
                g =  new OpenLayers.Format.JSON();
                resp = g.read(response.responseText);
                attrdata = new Array();
                for (i in resp.features) {
                attrdata[i] = resp.features[i].properties.attr1; }
                   }

I hope I included all the parts needed. Anyway after this I have an 
array of attributes (attr1) of the chosen geometries. I guess CQL_FILTER 
is Geoserver specific and JSON isn't mandatory format in wfs compliant 
server, but of course there could be used standard FILTER and GML output 
with 'getElementsByTagName' or similar.

- mika -