[OpenLayers-Users] reprojection of vector layer from wgs84 to sphericalmercator

[Mike Adair]

Note that this should work too, and allows you to handle points in 
coordinate systems other than EPSG:4326:

- include proj4js in your app via the <script> tag

- then:

preFeatureInsert = function(feature) {
    var src = new OpenLayers.Projection('EPSG:4326');
    var dest = new OpenLayers.Projection('EPSG:900913');
    for (var i = 0; i < feature.geometry.components.length; i++) {
	OpenLayers.Projection.transform(feature.geometry.components[i], src, dest);
   }
};

You may need to skip transforming the last point in the components if it is a repeat of the first point (for polygons).

Mike



Jachym Cepicky wrote:
> Hi,
>
> Jachym Cepicky píše v Po 14. 01. 2008 v 14:11 +0100:
>   
>> [...]
>>
>> Then I tried to redefine preFeatureInsert method of OpenLayers.Layer.Vector, to get coordinates 
>> for all features in epsg:900913
>>
>> preFeatureInsert = function(feature) {
>>     for (var i = 0; i < feature.geometry.components.length; i++) {
>>         var x = feature.geometry.components[i].x;
>>         var y = feature.geometry.components[i].y;
>>         var ll = kolo.forwardMercator(x,y);
>>         
>>         x = x * 20037508.34 / 180;
>>         y = Math.log(Math.tan((90 + y) * Math.PI / 360)) / (Math.PI / 180);
>>
>>         y =  y * 20037508.34 / 180;
>>
>>         feature.geometry.components[i].x = x;
>>         feature.geometry.components[i].y = y;
>>         
>>    }
>> };
>>
>>    // the vector map definition
>>   
>>   var vector = new OpenLayers.Layer.GML("Vector","gml.xml",
>> 			{preFeatureInsert:preFeatureInsert});
>>
>>     
> this works. the error was somewhere else
>
> j
>   
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