在OpenLayers Map中更改投影

Question

我想将"EPSG:4326"设置为OpenLayers地图的投影,但是当我尝试它时,我总是得到"EPSG:900913".

function init() {

    var options = {
            projection: new OpenLayers.Projection("EPSG:4326")  // ignored
    };

    map = new OpenLayers.Map('map', options);

    var layer = new OpenLayers.Layer.OSM.Osmarender("Osmarender");
    map.addLayer(layer);

    ...

    alert(map.getProjection());  // returns "EPSG:900913"

    ...

}

基本地图是开放的街道地图.

如何将投影设置为EPSG:4326？

Answer 1

正如milovanderlinden指出的那样,你必须先转换纬度/经度值(如Google或Bing地图中所使用的那样),然后才能在OpenStreetMap图层中应用,Osmarender或者Mapnik:

var datapoint = new OpenLayers.LonLat(-71.0, 42.0);
var proj_1 = new OpenLayers.Projection("EPSG:4326");
var proj_2 = new OpenLayers.Projection("EPSG:900913");
datapoint.transform(proj_1, proj_2);