Makes sense, I only fish Puget Sound and can say it has been mapped rather well by now. It still isn't 100% accurate (and won't likely ever be), but pretty dang close for the places I have been. I'm probably at 90% for finding a place and having it look like it did on the map and hold the fish I'm looking for. Every once in a while something is just not right or the current is such that it never slacks enough to fish effectively.