1. For use with proximity correction of dosage in lithography processing of a pattern of area features to form an integrated circuit device, a method of locating those area features which lie within a prescribed proximity correction neighborhood of a respective area feature, comprising the steps of: (a) for each of a plurality of distance increments extending in a first direction across said pattern, examining said pattern to identify those area features which are located within a respective area window extending in a second direction from a respective distance increment, and generating and storing information representative of characteristics of each identified area feature in a group that is associated with that respective area window; (b) for each of the area features whose identities have been stored in respective groups in step (a), defining a boundary window which delineates said prescribed proximity correction neighborhood relative to that respective area feature; and (c) for a respective area feature, identifying those area features that have been stored in step (a) and characteristics of which are contained within the boundary window for said respective area feature as lying within said prescribed proximity correction neighborhood of said respective area feature.