Refining Geographic Attribution

The locations of our geographic entities will have four gross classes of attribution:

None
The class of entities for which there is no known geographic location.
Weak
The class of entities which have weakly attributed locations, and can not be plausibly placed on a map. For example: "island in the Aegean", "on the Adriatic Coast", "East of the Danube River".
Approximate
The class of entities which have locations attributed strongly enough that they can be plausibly placed on a map. This corresponds to the Barrington Atlas's approximate certainty of locations.
Known
Corresponds to the BA's known certainty of location.