int getMinLonForTile(double lon) {
        return (int) (Math.floor((180 + lon) / LON_DEGREE) * LON_DEGREE) - 180;
    }
@Test
    public void testMinLon() {
        assertEquals(-60, instance.getMinLonForTile(-59.9));
        assertEquals(0, instance.getMinLonForTile(0.9));
    }