Method of describing settlement patterns based on territorial divisions centered on a single site or feature (locational analysis); the polygons are created by drawing straight lines between pairs of neighboring sites, then at the mid-point along each of these lines, a second series of lines are drawn at right angles to the first. Linking the second series of lines creates the Thiessen polygons. Where the exact boundaries between ancient territories are undetermined, an attempt to reconstruct them can be made if the distribution of focal points (central place), one to each territory, is known. The assumption is that any point will be dependent on the nearest central place. Thiessen polygons are useful for defining theoretical territories related to each center - an area of production, a source of an important material, or a market center. These theoretical territories can be tested by comparison with actual archaeological data such as artifact distributions.