Half normal range...

I was wondering if anybody knew exactly how this works. Ex. Caltrops (assasin skill) have half normal range, half range of what? Your normal attack range? If so, what is that? Is there some formula that it plugs numbers into to determine the actual range at which it may be used? Anybody know?

Caltrops is considered a spell, as such it has a range that is half the normal range of a spell such as flare. You can find out more on the guildwiki, specifically, this page

http://gw.gamewikis.org/wiki/Range

its half normal spell range. (about half your aggro bubble)