code: @Override
    public int compareTo(final PointLocation pointLocation)
    {
      int comparison;
      comparison = (int) Math.signum(altitude - pointLocation.altitude);
      if (comparison == 0)
      {
        comparison = latitude.compareTo(pointLocation.latitude);
      }
      if (comparison == 0)
      {
        comparison = longitude.compareTo(pointLocation.longitude);
      }
      return comparison;
    }
docs: {@inheritDoc}
  
  @see java.lang.Comparable#compareTo(java.lang.Object)