LOS line of sight on units NEEDED

I think its needed because sometimes we see for example a unit like a rodeler or a inca unit that i forgot the name but runs at 6.5 speed walking around our villagers and i dont know if the enemy player now has units of my color on the minimap, or he just pass walking and didnt appear my units on enemy player minimap because i was out of line of sight.
With number of line of sight on stats i could calculate aproximately by seeing the map if he didnt kill my villagers because he wasnt putting attention to that zone of the map, or because he just couldnt see my because i was out of his units’ range of vision
also i just dont know what is the line of sight of every unit.
I dont know if cavalry has more line of sight etc.