What are "action zones" (and maybe how to use this stat for adjustment)?

[Bahnzo]

 

Here's one from a recent match, about the 60th min. The action zone listed on the bottom is what I never have quite understood. Does this mean that Werder is having most of the possession in the midfield? Because the actual stats don't match that. 

And also, do you use it for mid match analysis and if so, then how?