int getMinLatForTile(double lat) {
        return (int) (Math.floor((90 + lat) / LAT_DEGREE) * LAT_DEGREE) - 90;
    }
@Test
    public void testMinLat() {
        assertEquals(50, instance.getMinLatForTile(52.5));
        assertEquals(10, instance.getMinLatForTile(29.9));
        assertEquals(-70, instance.getMinLatForTile(-59.9));
    }