In this paper, we present a quality evaluation of two-dimensional building acquisition. We propose methods for identification and quantification of differences between independently acquired regions, and we present a systematic classification of those differences. Differences between acquired sets R-j = {r(i)}(j) of region r(ij) depend on the context of observation, on the technique of observation, etc. We distinguish topological and geometrical differences. Topological differences refer to the interior structure of a set of regions as well as to the structure of the boundary of a single region. Geometrical differences refer to the location of the boundary of a single region or of a set of regions, independent of their representation and of the structure of the boundaries. Identification of differences requires a matching of two data sets R-1 and R-2, which is done here by weighted topological relationships. For the identification of topological differences between two sets R-1 and R-2 of regions, we use the two region adjacency graphs (RAGs). For an identification of geometrical differences, we use the zone skeleton between two matched subsets r(p1) and r(q2) of the given sets. The zone skeleton is labeled with the local distances of the corresponding boundaries of the subsets; especially, we investigate its density function. An example based on two real data sets of acquired ground plans of buildings, shows the feasibility of the approach. (C) 2000 Elsevier Science B.V. All rights reserved.