A method for scanning a semiconductor layout, the layout comprising objects with edges and corners, the method comprising identifying locally closest point pairs, identifying a proximity relation between two parallel edges where the parallel edges have at least one locally closest point pair in common and storing the proximity relation in a proximity relations table of a database together with a reference to the corresponding pair of edges. Locally closest point pairs are identified where the first edge and the second edge are not in contact with each other, a distance between the first point and the second point is the shortest distance between the first edge and the second edge, and a convex bounding area with the first point and the second point on its boundary contains no edge.