What this article does not provide is information about the kibbutzim and moshavim near Gaza which would have given their fields away. I assume that Olmert had discussed this with them and received their agreement. This would be an extremely important information to convey to the public, not only international but also to the Israeli public.
At least 1,000 Israeli Arabs protest death of Palestinian infant in deadly West Bank arson (Haaretz)
from the article: Abbas: Olmert offered PA land equaling 100% of West Bank