Wie zu Lesen externe GeoJSON-Datei von openlayers?

Ich haben, zeichnen Sie einige Linien von OpenLayers. Die Linie Funktionen codiert sind, als GeoJSON-format. Mein code ist ok für hart codiert GeoJSON features. Aber, wenn ich diese Funktionen in separate Datei, und versuchen Sie es zu laden. Es funktioniert einfach nicht. Ich weiß nicht, was ist falsch mit meinem laden von externen GeoJSON-Datei. Ich habe sowohl den code.

Code 1:

//This code is ok with hard coded GeoJSON features
map.addControl(new OpenLayers.Control.LayerSwitcher());

            vectorLayer = new OpenLayers.Layer.Vector("Lines");

            var myGeoJSON = { "type": "FeatureCollection",
                "features": 
                [

                    { "type": "Feature", "properties": { "LENGTH": 756.304000}, "geometry": { "type": "LineString", "coordinates": [ [ 18.105018, 59.231027 ], [ 18.104176, 59.230737 ], [ 18.103928, 59.230415 ], [ 18.103650, 59.230336 ], [ 18.103028, 59.230463 ], [ 18.102491, 59.230418 ], [ 18.101976, 59.230237 ], [ 18.100893, 59.230110 ], [ 18.100117, 59.230016 ], [ 18.097715, 59.230262 ], [ 18.096907, 59.230376 ], [ 18.096637, 59.230405 ], [ 18.096578, 59.230428 ], [ 18.096429, 59.230450 ], [ 18.096336, 59.230479 ], [ 18.096108, 59.230534 ], [ 18.095971, 59.230600 ], [ 18.095925, 59.230633 ], [ 18.095891, 59.230665 ], [ 18.094000, 59.231676 ], [ 18.093864, 59.231720 ] ] } }
                    ,                   
            { "type": "Feature", "properties": { "LENGTH": 1462.390000}, "geometry": { "type": "LineString", "coordinates": [ [ 17.877073, 59.461653 ], [ 17.877116, 59.461598 ], [ 17.876936, 59.461507 ], [ 17.876936, 59.461323 ], [ 17.876773, 59.461098 ], [ 17.876430, 59.460885 ], [ 17.876413, 59.460553 ], [ 17.876576, 59.460280 ], [ 17.876575, 59.460078 ], [ 17.876762, 59.460060 ], [ 17.877371, 59.460042 ], [ 17.877808, 59.460046 ], [ 17.878641, 59.460046 ], [ 17.879010, 59.460078 ], [ 17.879337, 59.460044 ], [ 17.879526, 59.459878 ], [ 17.879749, 59.459563 ], [ 17.880058, 59.459538 ], [ 17.880435, 59.459503 ], [ 17.887550, 59.453608 ], [ 17.887696, 59.453430 ], [ 17.887971, 59.453150 ], [ 17.888221, 59.452843 ], [ 17.888246, 59.452721 ], [ 17.888435, 59.452609 ], [ 17.888470, 59.452568 ], [ 17.888517, 59.452410 ] ] } }

                ]
            };

            var geojson_format = new OpenLayers.Format.GeoJSON({
                'internalProjection': map.baseLayer.projection,
                'externalProjection': new OpenLayers.Projection("EPSG:4326")
            });


            map.addLayer(vectorLayer);

            vectorLayer.addFeatures(geojson_format.read(myGeoJSON));

            map.setCenter(
                new OpenLayers.LonLat(18.068611, 59.329444).transform(
                    new OpenLayers.Projection("EPSG:4326"),
                    map.getProjectionObject()
                ), 10
            );

Code 2: Dieser code enthält einen Fehler, es konnte nicht geladen werden features

//This code does not work because it can not load the external GeoJSON file

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

vectorLayer = new OpenLayers.Layer.Vector("Lines");

var myGeoJSON = new OpenLayers.Layer.Vector("Lines", {
    strategies: [new OpenLayers.Strategy.Fixed()],                
    protocol: new OpenLayers.Protocol.HTTP({
           url: "ml/lines.json"

           })
     });

var geojson_format = new OpenLayers.Format.GeoJSON({
    'internalProjection': map.baseLayer.projection,
    'externalProjection': new OpenLayers.Projection("EPSG:4326")
    });

map.addLayer(vectorLayer);

vectorLayer.addFeatures(geojson_format.read(myGeoJSON));

map.setCenter(
     new OpenLayers.LonLat(18.068611, 59.329444).transform(
         new OpenLayers.Projection("EPSG:4326"),
             map.getProjectionObject()
                ), 10
            );

Vielen Dank im Voraus

InformationsquelleAutor der Frage Shahjalal | 2012-04-29