How did the tape measure come from?

The inventor of the world's first tape measure was Cheng Dawei, a famous mathematician, abacus operator and inventor in Ming Dynasty. He invented it around 1578. He called it "measuring walking bicycle" at that time, so Cheng Dawei was called "the father of tape measure". Compared with the existing steel tape and leather tape, the "measuring device" is much larger, but from its principle, structure, use and usage, it is the prototype of tape measure. It consists of a wooden coat, a cross, a bamboo ruler, an iron swivel, a drill foot and a ring. The rod ruler is put in and taken out from the plate hole of the jacket, which is convenient for the drilling foot to be accurately inserted into the field measurement point and easy to carry. Prior to this, "the ancients measured fields wider and longer, and measured them completely by rope ruler", which was not only labor intensive, but also had a high error rate. The value of Cheng Dawei lies in the inspiration of replacing the rope with a flat ruler. This revolutionary achievement has been strictly enjoyed by tape measure until now.