public static double getWorldLat(double y) {
    double n = Math.PI - 2 * Math.PI * y;
    return DEGREES_PER_RADIAN * Math.atan(0.5 * (Math.exp(n) - Math.exp(-n)));
  }
Returns the latitude for a web mercator {@code y} coordinate where 0 is the north edge of the map, 0.5 is the
equator, and 1 is the south edge of the map.
planetiler-core/src/main/java/com/onthegomap/planetiler/geo/GeoUtils.java