magnetic declination 地磁偏角 ; [地物] 磁偏角 ; 磁差

magnetic declination diagram 磁偏角略图

declination of magnetic needle 磁偏角

magnetic c declination 磁偏角

MAG DEC Magnetic Declination 磁偏角 ; 磁偏移

magnetic needle declination 磁针偏角

map magnetic declination 图幅磁偏角

magnetic declination angle [地物] 磁偏角

expected magnetic declination 磁偏角期望值

measured magnetic declination 磁偏角实测值