primary datum

Technical Notes: October 2012 ... 工艺基准 process datum 主要基准 primary datum 次要基准 secondary datum ...

美英加陆军规格_馆档网 ... "原图表"," primary chart" "主基准"," primary datum" "主基线"," primary ground line" ...

在线词典--水电知识网-... ... ordinance datum 法定基准面 primary datum 主基[准]面 reference datum 参考基准面 ...