API & Defaults Discussion

OpenLayers 3 should provide an API that makes it easy to accomplish common use cases. People who do not need to leverage the full functionality should be provided fast lanes for a leaner and easy to use configuration. Defaults should be set in the right places to avoid duplicated code.

Map with WMS layer (tiled) in default projection (EPSG:3857)

new ol.Map({
    layers: [
        // suitable layer type can be chosen based on the source
        new ol.source.TiledWMS({
            url: '/geoserver/wms',
            params: {
               'LAYERS': 'usa:states' // would be nice without quotes for the key
            }
        })
    ],
    // would be even nicer to provide center and zoom as direct map config options
    view: {
        center: [47, 15],
        zoom: 9
    }
});

Map with custom projection and a WMS layer

new ol.Map({
    layers: [
        // suitable layer type can be chosen based on the source
        new ol.source.TiledWMS({
            url: '/geoserver/wms',
            params: {
               'LAYERS': 'usa:states' // would be nice without quotes for the key
            }
        })
    ],
    // would be even nicer to provide center and zoom as direct map config options
    view: {
        projection: {
            code: 'EPSG:31256',
            extent: [-115317.3972, 151511.8020, 64307.1064, 432456.2246]
        },
        center: [47, 15],
        zoom: 3
    }
});

The layer source should not need a projection configuration - it should get it from the view. With the projection's extent, the layer source should be able to create a default tile grid.