[GIS] How to get feature id for particular feature after feature ismodify in OpenLayers

openlayers-2

I am using modify control in OpenLayers 2.12. After feature is modified I am running the function below:

building.events.register('afterfeaturemodified',building, onchanges);

Where building is my WFS layer. Now in "onchanges" function runs and now I want my WFS feature id/name, etc.

My function is as follows:

function onchanges(ev)
        {
            var polygonch=ev.feature.geometry;
        }

Now in this function I want feature id/name on which modification is done. Or other method to get feature info on which editing/modification is done.

Best Answer

You just need to call for the feature id, the same way you would for the feature geometry:

 changed_polygon_id = ev.feature.id;

Option #1:

Use a click Handler (EXAMPLE).

and Inside click trigger build the infoWindow like so:

...
trigger: function(e) {
   var feature = geojson_layer.getFeatureById(e.target._featureId); //<--feature being clicked on.
   map.addPopup(new OpenLayers.Popup.FramedCloud(
        "chicken", 
        map.getLonLatFromPixel(e.xy),
        null,
        "some text",
        null,
        true
    ));
}
...

You can determine/retrieve the feature which is being clicked on by doing var feature = geojson_layer.getFeatureById(e.target._featureId);

Option #2:

Use the OpenLayers.Control.SelectFeature control. This example includes the infoWindow (popup)

selectControl = new OpenLayers.Control.SelectFeature(geojson_layer, {
    onSelect: function(){...},
    onUnselect: function(){...}
});
map.addControl(selectControl);
selectControl.activate();

OpenLayers 2 GeoServer Style – Cloned Features Getting Style from Original Feature

I attacked the problem from a different direction. Instead of trying to make it work using clone() or addFeatures I ended up using the WKT method. It probably isn't the best solution to the problem but it works. Here is the code I am using now:

function createSelectedFeatureLayer(selectItems) { 
//GET THE NAME OF THE LAYER TO SELECT FROM
var mLayer = map.getLayersBy('name', 'Test Stands 4thQ 2012' );
//SET A VARIABLE TO THE LAYERS FEATURE ARRAY
var layerFeatureArray = mLayer[0].features; 
//SET UP A STYLE MAP FOR THE FEATURES WE ARE GOING TO CREATE
var vctrStyleMap = new OpenLayers.StyleMap({
    fillColor: '#FF0000', 
    fillOpacity: 0.5,
    strokeColor: '#FF0000',
    strokeWidth: 2.5
});

//CREATE A NEW VARIABLE TO HOLD A WELL KNOWN TEXT OBJECT
wkt = new OpenLayers.Format.WKT();
//CREATE A NEW EMPTY VECTOR LAYER TO HOLD THE FEATURES WE WILL CREATE - ASSIGN THE STYLEMAP VARIABLE TO IT
vectors = new OpenLayers.Layer.Vector("Search Results", { styleMap: vctrStyleMap });
//ADD THE NEW EMPTY VECTOR LAYER TO THE MAP OBJECT
map.addLayer(vectors);

//selectItems IS AN ARRAY OF VALUES I AM MATCHING AGAINST - LOOP THROUGH THIS LIST
for (a = 0; a < selectItems.length; a++) {
//LOOP THROUGH THE FEATURES ARRAY FROM THE LAYER WE ARE SELECTING FROM
    for (x = 0; x < layerFeatureArray.length; x++) {
//IF THE UID OF THE FEATURE FROM THE SELECTION LAYER MATCHES THE VALUE FROM THE INPUT ARRAY
        if (layerFeatureArray[x].attributes['UID'] == selectItems[a]) {                
            //SET A VARIABLE TO THE FEATURE
            var searchFeature = layerFeatureArray[x];
            //SET A VARIABLE TO THE WELL KNOWN TEXT VALUE OF THE FEATURE OBJECT - WRITE IT!
            var str = wkt.write(searchFeature);
            //READ THE WELL KNOWN TEXT STRING AND ASSIGN IT TO THE features VARIABLE
            var features = wkt.read(str);
            //ADD THE FEATURE TO THE VECTOR LAYER WE CREATED EARLIER
            vectors.addFeatures(features);

            break;
        }//END if 
    } //END feature array FOR LOOP  
} //END selItems array FOR LOOP

vectors.redraw();//REDRAW THE LAYER
map.zoomToExtent(vectors.getDataExtent()); //ZOOM TO THE NEW LAYERS 
map.setLayerZIndex(vectors, 100); //PUT THE SELECTION LAYER ON TOP

}

Best Answer

Related Solutions

OpenLayers 2 GeoJSON – Adding an Infowindow to an OpenLayers GeoJSON Layer

Option #1:

Option #2:

OpenLayers 2 GeoServer Style – Cloned Features Getting Style from Original Feature

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