needs customization

define tile server and layer

	    
	        this.osm = new ol.layer.Tile({
                source: new ol.source.OSM()
            });
	    
    

define view (center, projection, zoom)

	    
	        this.view =  new ol.View({
                center: ol.proj.fromLonLat([23.82, 37.41]),
                zoom: 6
            });