function normalize(gj) {
	    if (!gj || !gj.type) return null;
	    var type = types[gj.type];
	    if (!type) return null;
	
	    if (type === 'geometry') {
	        return {
	            type: 'FeatureCollection',
	            features: [{
	                type: 'Feature',
	                properties: {},
	                geometry: gj
	            }]
	        };
	    } else if (type === 'feature') {
	        return {
	            type: 'FeatureCollection',
	            features: [gj]
	        };
	    } else if (type === 'featurecollection') {
	        return gj;
	    }
	}
Normalize a GeoJSON feature into a FeatureCollection.

@param {object} gj geojson data
@returns {object} normalized geojson data