understanding "visible" units in F10 maps

[chromium]

Hi,

 

I would like to understand how enemy units are shown in the F10 "fog of war" map view: has the "is detected" command used?

 

at the moment I have a script that prints out a csv file of any visibile units by any allied units (within a range that take into account real curvature of the earth), but I prefer to reproduce the same logic that the sim use to make visibile enemy units in F10 map.

 

Any suggestion? :)