具有OpenLayers.Control.GetFeature的OpenLayers.Class

Question

I'm wondering if someone could point me in the right direction to force the BBOX of OpenLayers.Control.GetFeature to be always in long/lat coordinates. I'm trying to get this with OpenLayers.Class, so the new control will inherit OpenLayers.Control.GetFeature with just the small modification in BBOX. This is what I've done:

OpenLayers.Control.myGetFeature = OpenLayers.Class(OpenLayers.Control.GetFeature,{
        selectBox: function(position){
            var opts = OpenLayers.Control.GetFeature(position);
            var baseSRSutm = this.map.getprojectionObject();
            var layerSRSdd = new OpenLayers.Projection('EPSG:4326');
            opts.params.bbox = this.map.getExtent().transform(baseSRSutm,layerSRSdd).toBBOX(null,firstLayer.reverseAxisOrder());
        }
        return opts;
    });

but I'm getting that some "}" are missing. Is this the right way to use OpenLayers.Class to do what I want?

Any help is much appreciated.

PS. I'm using OpenLayers 2.11

EDIT:

Moving "return opts;" inside the function solved the above problem but it complained about CLASS_NAME is missing. Adding that, it still complained about the same, but after a couple of clicks or boxes it sent the request, however the sent bbox is still in UTM, where could the problem be? here it is the code:

var mycontrol = function(){
        var protocol = new OpenLayers.Protocol.HTTP({
            url: 'http://www.....',
            format: new OpenLayers.Format.GeoJSON({
                ignoreExtraDims: true,
                'internalProjection': new OpenLayers.Projection('EPSG:900913'),
                'externalProjection': new OpenLayers.Projection('EPSG:4326')
            })
        });

        OpenLayers.Control.myGetFeature = OpenLayers.Class(OpenLayers.Control.GetFeature,{
            selectBox: function(position){
                var opts = OpenLayers.Control.GetFeature(position);
                var baseSRSutm = this.map.getprojectionObject();
    console.log('this is the baseSRSutm' + baseSRSutm); // doesnt appear in firebug
                var layerSRSdd = new OpenLayers.Projection('EPSG:4326');
                opts.params.bbox = this.map.getExtent().transform(baseSRSutm,layerSRSdd).toBBOX(null,firstLayer.reverseAxisOrder());
    console.log('this is the opts.params.bbox' + opts.params.bbox); // doesnt appear in firebug
                return opts;
            },
            CLASS_NAME: "OpenLayers.Control.myGetFeature"
        });

      return new OpenLayers.Control.myGetFeature({
            protocol: protocol,
            box: true,
            click: true,
            single: false,
            clickTolerance: 10,
            eventListeners:{
                // some stuff
            }
        });
    };

because the console.log doesn't appear in firebug, I think the problem is in the OpenLayers.Control.myGetFeature and OpenLayers.Class. It seems to me that the "selectBox" function is the one I need, but the subclass itself is not read by the return.

Please help on this one, thanks in advance,

Answer 1

Your code sample has some syntax errors. Try using some javascript code linters like jsHint in the future to help debug these errors. Here's your code, fixed:

OpenLayers.Control.myGetFeature = OpenLayers.Class(OpenLayers.Control.GetFeature,{
    selectBox: function(position){
        var opts = OpenLayers.Control.GetFeature(position);
        var baseSRSutm = this.map.getprojectionObject();
        var layerSRSdd = new OpenLayers.Projection('EPSG:4326');
        opts.params.bbox = this.map.getExtent().transform(baseSRSutm,layerSRSdd).toBBOX(null,firstLayer.reverseAxisOrder());
        return opts;
    }
});

With regards to your question about a custom GetFeature, I think you're on the right track. This is the same approach I'd take. OpenLayers recommends a slightly different approach in their examples , but it performs the same function:

var control = new OpenLayers.Control.GetFeature();
OpenLayers.Util.extend(control, {
    selectBox: function(position){
        var opts = OpenLayers.Control.GetFeature(position);
        var baseSRSutm = this.map.getprojectionObject();
        var layerSRSdd = new OpenLayers.Projection('EPSG:4326');
        opts.params.bbox = this.map.getExtent().transform(baseSRSutm,layerSRSdd).toBBOX(null,firstLayer.reverseAxisOrder());
        return opts;
    }
});

Answer 2

终于成功了，诀窍是使用原型和selectBox，然后在基础地图投影和displayProjection之间进行转换，在这种情况下，介于900913和4326之间。我在这里得到了这个主意： http：//osgeo-org.1560 .n6.nabble.com / Order-Priority-of-Control-GetFeature-and-Control-WMSGetFeatureInfo-on-click-td4997282.html