jgg     2014 34 (5):  151-155    ISSN: 0412-1961  CN: 21-1139/TG STUDY ON SELECTION OF GEOMAGNETIC SUITABLE MATCHING  AREA  BASED ON IMPROVED GEOMAGNETIC ENTROPY The Second Artillery Engineering University，Xi’an 710025 Received: 2014-01-15  Revised: null  Online: 2014-09-26 Supporting info