Question about Fortresses

[PrinceMiskin]

Fortresses seem to be marked with a +2 survivability bonus. How does this translate to game engine, does it add a +2 modifier to any stationary unit?

Thanks,
Mysh

[firepowerjohan]

Survivability of reources is only used in strategic battle, not unit battle. So if you attack a fort or city with a strategic bomber or if you strike a empty resource then you are going up against it, else you go up against the unit.
 
The fortress attack penalty is what is used deciding your penalty in a battle vs defending unit.

[PrinceMiskin]

Thanks! [:)]