Digital maps created in the process of digitising of cartographic materials contain a lot of topological errors. The sources of these errors are: the qualities of the digitising method and the operator's mistakes. Digital maps which are not cor-rect in terms of topology cannot be used in the vector data processing systems. The special case of topological errors of digital maps is the disagreement of the course of plot boundaries and the functional grounds boundaries. The authors have cre-ated and implemented an algorithm which corrects such errors and which is based on the correction of the course of functional grounds boundaries in the area sur-rounding a given segment of the plot boundary. The program which uses the above algorithm is highly efficient. ...