Area-patch generalisation: a competitive approach

AbstractA solution to the automated generalisation of one particular class of geographical objects is proposed. Those objects are area patches distributed over a two-dimensional space. They are assumed to be semantically identical; hence the competition for space occurs on the basis of geometric considerations only. The solution proposed is algorithmic, stepwise and works for vector data only. The steps include data preprocessing, area expansion and contraction, elimination, reselection, aggregation, displacement, integrity check, smoothing and reduction. Among the generalisation rules which were applied are: (1) emphasis on larger patches at the expense of smaller ones, (2) preservation of the overall figure/group relationship, (3) partial topological integrity, and (4) differential displacement according to patch area. Results are discussed within the wider framework of topographic map generalisation where diversified objects must be simultaneously generalised.