Having % Increased Evasion Rating on a piece of gear, will it increase the Evasion Rating of my whole character or only of that piece?
- Example Item: http://pathofexile.gamepedia.com/Ondar%27s_Flight
That particular modifier is a local modifier, meaning it only affects the item in question. Global modifiers almost never appear on items that have the property being modified.
Mark explains it here, but basically if the item can have the property being modified, the modifier is local. If you get +100% evasion on a piece of armor, it's local (armor only). If you get +100% evasion on a ring, which has no base evasion because it's a ring, it has to be a global modifier.
TL:DR; Assume it is a local modifier, unless it makes no sense, then it has to be a global one.