public static double decodeWorldY(long encoded) {
    return ((encoded & LOWER_32_BIT_MASK) / HALF_QUANTIZED_WORLD_SIZE) - 1;
  }
Returns the web mercator Y coordinate of the latitude/longitude encoded with
{@link #encodeFlatLocation(double, double)}.
planetiler-core/src/main/java/com/onthegomap/planetiler/geo/GeoUtils.java