Narrowing it down to even a 100km radius for visint analysts to then pinpoint it down is worth its weight in gold already.

A 40km radius circle is far smaller than a 1000 km radius circle.

Once the guesser's made its attempt, it's more straightforward to either refute the guess entirely, or refine within a probable circle of error.

40km accuracy for something arbitrary is a decent starting point. I can normally get within a few meters within a couple of minutes of most images though.