[OpenLayers-Users] drawing a geojson layer

[Puneet Kishor]

On Sep 23, 2011, at 3:05 PM, <christopher.schmidt at nokia.com> wrote:

> Are you using OSM? Did you reproject your coordinates anywhere?


No, I am using Google Maps base layer. My data are in lat/lng, so I believe this s a re-projection issue.

I redefined my map like so

            map = new OpenLayers.Map("map", {
                controls: [
                    new OpenLayers.Control.LayerSwitcher(),
                    new OpenLayers.Control.MousePosition({div:document.getElementById("coords")})
                ],
                projection: new OpenLayers.Projection("EPSG:900913"),
                displayProjection: new OpenLayers.Projection("EPSG:4326")
            });


and then

            var vector_layer = new OpenLayers.Layer.Vector(
                "vector layer", 
                {projection: new OpenLayers.Projection("EPSG:4326")}
            );
            map.addLayer(vector_layer);

and then 

           var geojson_format = new OpenLayers.Format.GeoJSON();
           vector_layer.addFeatures(geojson_format.read(featurecollection));

I am assuming that is not the right way, because that is not working. Do I have to transform every point one by one?


> 
> -- Chris
> 
> On Sep 23, 2011, at 3:07 PM, ext Puneet Kishor wrote:
> 
>> I have a fairly straightforward code like so, with the JSON data coming out of Pg. I am using OL 2.11
>> 
>>   var data = {
>>     "type" : "FeatureCollection"
>>     "features" : [
>>        {
>>           "geometry" : {
>>              "coordinates" : [[[x1, y1], [x2, y2], [x3, y3]]],
>>              "type" : "MultiLineString"
>>           },
>>           "type" : "Feature",
>>           "properties" : {"code" : 101, "desc" : "blah" }
>>        },
>>        {
>>           "geometry" : {
>>              "coordinates" : [[[x1, y1], [x2, y2], [x3, y3]]],
>>              "type" : "MultiLineString"
>>           },
>>           "type" : "Feature",
>>           "properties" : {"code" : 102, "desc" : "blah" }
>>        },
>>        {
>>           "geometry" : {
>>              "coordinates" : [[[x1, y1], [x2, y2], [x3, y3]]],
>>              "type" : "MultiLineString"
>>           },
>>           "type" : "Feature",
>>           "properties" : {"code" : 103, "desc" : "blah" }
>>        },
>>     ]
>>   }
>> 
>>   var geojson_format = new OpenLayers.Format.GeoJSON();
>>   var lyr = new OpenLayers.Layer.Vector("layer name"); 
>>   PK.vars.map.addLayer(lyr);
>>   trenches.addFeatures(geojson_format.read(data));
>> 
>> Yet, no errors and no features drawn on the map. What am I doing wrong?
>> 
>> Puneet._______________________________________________
>> Users mailing list
>> Users at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/openlayers-users
>