{z}/{x}/{y}.png", {opacity: 0.3, attribution: 'map data &copy; OpenStreetMap contributors, imagery <a target="_blank" href="http://ihned.cz">IHNED.cz</a>'}).addTo(map);
            L.control.layers(null, {
                "SVG Mapper output": svgMapper,
                "OSM Imagery": osmImagery
            }).addTo(map);
            utfGrid.on('mouseover', function (e) {
                var str = e.data;
                tooltip.display(str);
            });
            utfGrid.on('mouseout', function (e) {
