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I have a "rich" application (OL 2.13 + GeoExt 1) where some layers must be styled dynamically according to user input. I am able to add a vector layer using WFS and then apply a style rule. Recently, some users started complaining the feature is not working. Eventually I found out some WFS layers are not being portrayed in the map canvas by OL.

Below is a minimum example with a simple map and one of the problematic layers. After loading all objects the debugger shows a vector layer within the map object; this vector layer is reported as visible and with the drawn property set to true. In the features array there are 8 objects as expected, but there is nothing visible in the map. There are no errors reported in the console.

I am able to display this same layer through WFS in QGIS and access all its attributes without trouble.

What is going wrong here?

<html>
<head>

 <script type="text/javascript" src="http://localhost/spatiallib/OpenLayers-2.13.1/OpenLayers.js"></script>
 <link rel="stylesheet" type="text/css" href="http://localhost/spatiallib/OpenLayers-2.13.1/theme/default/style.css">

 <script type="text/javascript">

function initMap()
{
    // Do not forget to add maps.iguess.tudor.lu to the proxy's allowed addresses
    OpenLayers.ProxyHost = "http://localhost/cgi-bin/proxy.cgi?url=";

    var mapProjection = "EPSG:31467";
    var mapServicePath = "http://maps.iguess.tudor.lu/cgi-bin/mapserv?map=srv/mapserv/MapFiles/LB_localOWS_test.map";

    var bounds = new OpenLayers.Bounds(3500000,5410000,3525000,5425000);

    map = new OpenLayers.Map("MiniMap",{
        projection: new OpenLayers.Projection(mapProjection),
        units: "m",
        maxExtent: bounds,
    });

    map.addControl(new OpenLayers.Control.LayerSwitcher());

    var cityWMS =  new OpenLayers.Layer.WMS(
        "LB_urban_landuse",
        mapServicePath,
        {layers: "LB_urban_landuse",
         format: "image/png",
         srsName: mapProjection,
         transparent: "true",
         projection: new OpenLayers.Projection(mapProjection)},
        {isBaseLayer: true,
         visibility: true}
    );

    var testWFS = new OpenLayers.Layer.Vector("testWFS", {
        strategies: [new OpenLayers.Strategy.Fixed()],
        projection: new OpenLayers.Projection("EPSG:31467"),
        visibility: true,
        protocol: new OpenLayers.Protocol.WFS({
            version: "1.1.0",
            url: "http://maps.iguess.tudor.lu/cgi-bin/mapserv?map=/srv/mapserv/MapFiles/LB_localOWS_test.map",
            featureNS: "http://mapserver.gis.umn.edu/mapserver",
            featureType: "LB_sliders_test",
            srsName: "EPSG:31467"
        })}
    );

    map.addLayers([cityWMS, testWFS]);
    map.setCenter(new OpenLayers.LonLat(3514100,5417800), 7);

    testWFS.display(true);
}

 </script>
</head>
 <body onLoad="initMap();" style="margin:0px">
     <div  style="width:800px; height:600px; background:white" id="MiniMap"></div>
     <input type=button value="Click for debugger" onclick="debugger;"></input>
 </body>
</html>
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1 Answer 1

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Your problem may come from using WFS 1.1.0 with a coordinate system that has a northing-easting axis order. You can try these solutions:

  1. Use WFS 1.0.0 version. You can test that 1.1.0 sends coordinates as northing-easting

http://maps.iguess.tudor.lu/cgi-bin/mapserv?map=/srv/mapserv/MapFiles/LB_localOWS_test.map&service=WFS&version=1.1.0&request=getfeature&typename=LB_sliders_test&maxfeatures=100

<gml:posList srsDimension="2">5417870.977814 3514129.458722

while WFS 1.0.0 sends them as easting-northing

http://maps.iguess.tudor.lu/cgi-bin/mapserv?map=/srv/mapserv/MapFiles/LB_localOWS_test.map&service=WFS&version=1.0.0&request=getfeature&typename=LB_sliders_test&maxfeatures=100

<gml:coordinates>3514129.458722,5417870.977814
  1. Actually OpenLayers WFS protocol should be clever enough and flip axis automatically when needed but that may not be the case. You should be able to give a hint for OpenLayers with format option "xy" as in a rather similar case in OpenLayers WFS flip coordinates
formatOptions: {
       xy: false
}
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1
  • The behaviour is the same with WFS 1.0.0, but what you describe is indeed interesting. I'll try solution 2 and report back. What is solution 3?
    – Luís de Sousa
    Commented Oct 17, 2014 at 15:25

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