OpenLayers 3.2.1 - Change default projection

Question

I am having a difficult time trying to change the default projection of the map view.

Here is a JSFIDDLE: http://jsfiddle.net/qtcpjape/3/

$( document ).ready(function() {
    var proj = new ol.proj.Projection({
        code: 'EPSG:4326',
        units: 'm',
        extent: [-180.0000, -90.0000, 180.0000, 90.0000]
    });

    var map = new ol.Map({
        target: 'map',
        controls: [],
        layers: [
            new ol.layer.Tile({
                source: new ol.source.MapQuest({
                    layer: 'osm'
                })
            })
        ],
        view: new ol.View({
            center: [-90.78885827595732, 38.78662388327825],
            projection: proj,
            zoom: 15
        })
    });
});

I will be having GeoJSON coming from a REST call that is in EPSG:4326 and I would like to map it easily.

Right now, I cannot seem to get the map to change the projection and show the actual center.

Any help would be appreciated! Thanks!

tsauerwein tsauerwein · Accepted Answer · 2015-03-03T07:54:45

As you are using MapQuest tiles, your map has to be in EPSG:3857 ~~because ol3 does not support raster reprojection~~ (raster reprojection is supported since version 3.11.0 but for performance reasons it is usually recommend to reproject the vector data). But your GeoJSON vector data can be reprojected on-the-fly from EPSG:4326 to EPSG:3857 by setting the target projection on the vector source.

For example:

var vectorSource = new ol.source.GeoJSON({
  ...
  projection: 'EPSG:3857'
});


var vectorLayer = new ol.layer.Vector({
  source: vectorSource
});


var map = new ol.Map({
    target: 'map',
    controls: [],
    layers: [
        new ol.layer.Tile({
            source: new ol.source.MapQuest({
                layer: 'osm'
            })
        }),
        vectorLayer
    ],
    view: new ol.View({
        center: ol.proj.transform([6, 49], 'EPSG:4326', 'EPSG:3857'),
        zoom: 3,
        projection: 'EPSG:3857'
    })
});

See http://jsfiddle.net/qtcpjape/5/

OpenLayers 3.2.1 - Change default projection

2 Answers