/**
   * set lat and lon by using UTM coordinates
   *
   * @param strZone UTM-zone, e.g. 32U
   * @param strNorthing Northing component
   * @param strEasting Easting component
   */
  public void set(String strZone, String strNorthing, String strEasting) {
    LatLonPoint ll = new LatLonPoint();

    utm.zone_letter = strZone.charAt(strZone.length() - 1);
    utm.zone_number = Convert.toInt(strZone.substring(0, strZone.length() - 1));
    utm.northing = (float) Common.parseDouble(strNorthing);
    utm.easting = (float) Common.parseDouble(strEasting);

    ll = utm.toLatLonPoint(); // returns null if unvalit UTM-coordinates
    if (ll != null) {
      this.utmValid = true;
      this.latDec = ll.getLatitude();
      this.lonDec = ll.getLongitude();
    } else {
      this.latDec = 91;
      this.lonDec = 361;
    }
  }
 /** Checks, if the data of utm is valid, if not, utm ist calculated */
 private void checkUTMvalid() {
   if (this.utmValid) return;
   this.utm = MGRSPoint.LLtoMGRS(new LatLonPoint(this.latDec, this.lonDec));
   this.utmValid = true;
 }