public static double getWorldLon(double x) {
    return x * 360 - 180;
  }
Returns the longitude for a web mercator coordinate {@code x} where 0 is the international date line on the west
side, 1 is the international date line on the east side, and 0.5 is the prime meridian.
planetiler-core/src/main/java/com/onthegomap/planetiler/geo/GeoUtils.java