The three axes determine three planes,the -, - and - plane.which divide space into eight octants.To each pointin space corresponds an ordered triple of numbers.its Cartesian coordinates,which measure its directed distances from the three planes.

• 三个坐标决定三个坐标面；面；面；面；这些坐标面将空间分成八个卦限；空间中点每个点都对应一个有序三元组和分别表示点到三个坐标面的有向距离.