var distX = Utils.latLngDistance(minLat, minLng, minLat, maxLng);
    var distY = Utils.latLngDistance(minLat, minLng, maxLat, minLng);
    var zoom = this.getZoom();
    var bounds = this.getBounds();
    var sw = bounds.getSouthWest();
    var ne = bounds.getNorthEast();
    var mapDistX = Utils.latLngDistance(sw.lat(), sw.lng(), sw.lat(), ne.lng());
    var mapDistY = Utils.latLngDistance(sw.lat(), sw.lng(), ne.lat(), sw.lng());

    // calculate at zoom 20 the distance
    //console.log('zoom: ' + zoom + ' mapDistX: ' + mapDistX + ' mapDistY: ' + mapDistX);
    while (zoom < 20) {
        zoom++;
        mapDistX /= 2;
        mapDistY /= 2;
        //console.log('zoom: ' + zoom + ' mapDistX: ' + mapDistX + ' mapDistY: ' + mapDistX);
    }

    //console.log('zoom: ' + zoom + ' mapDistX: ' + mapDistX + ' distX: ' + distX);
    while (mapDistX < distX && zoom > 0) {
        mapDistX *= 2;
        mapDistY *= 2;
        zoom--;
        //console.log('zoom: ' + zoom + ' mapDistX: ' + mapDistX + ' distX: ' + distX);
    }

    console.log('zoom: ' + zoom + ' mapDistY: ' + mapDistY + ' distY: ' + distY);
    while (mapDistY < distY && zoom > 0) {
        mapDistY *= 2;
        zoom--;
        //console.log('zoom: ' + zoom + ' mapDistY: ' + mapDistY + ' distY: ' + distY);
    }

    return zoom;