This paper describes a method of reconstructing polygons by digitized line segments in a map coverage. The order and direction of digitization are arbitrary. Based on the analysis of topological relationships of the basic graphic unts: Polygon

Line and node

the emphasis of the discussion is placed on the linkage of Lines

the sequential searching for Lines which the polygon consists of

transaction of islands

and attribute coding of polygons. As a result

the series records related to the polygons are then produced for vector-based geographic information systems.