What is "split" in film production?

What is "split" in film production? Storyboard is sometimes translated directly into story map or storyboard. A notepad originally meant to arrange film shooting procedures. It is now one of the production tools of animation, film, TV series, advertising and other image media. It refers to explaining the composition of images in the form of charts before actual shooting or drawing, decomposing continuous pictures into one-time mirror operation unit, and marking the mirror operation method, time length, dialogue, special effects, etc. If we start to prepare the overall analysis of a film or the analysis of the narrative and splicing aspects of the film, then the mirror must be an indispensable tool. For the analysis of other aspects of the film, even if it is completely visual analysis, it is also a very useful tool because it can highlight the style of the film and the selection angle of decoration. The division is often edited and drawn by the director himself, and there are also special division engineers.