Because of my limited knowledge, I really don't know where the director copied the name of Manhattan measurement. But according to the later explanation, this is a mathematical model to infer the murderer's residence. This method is still possible. In addition to portraits of criminals, there are also geographical portraits. This kind of geographical portrait is called criminal geographical positioning, or GCT for short. This mathematical model uses the distance attenuation function to track the criminal's life direction through the place where the criminal abandoned the body, and infer the time and place of his next crime through the characteristics of the criminal's life, work and travel. GCT is a very complicated process, and it can't be calculated only by Qin Feng falling to the ground.

This mathematical model is based on the geographical description theory of criminals, that is, as far as serial killers are concerned, criminals often have a specific "crime area", and the victims are often not random, but regularly distributed from the suspect's residence, and he will not commit crimes in strange places too far from home; On the other hand, they probably won't commit crimes near their homes to avoid being discovered by acquaintances. Similarly, it is only a tool to assist criminal investigation and may not be used to solve crimes.