This paper details the application of geometric proportional analogies in the sub-classification of polygons within a topographic (land cover) map. The first part of this paper concerns geometric proportional analogies that include attributes (e.g. fill-pattern and fill-colour). We describe an extension to the standard theory of analogy that incorporates attributes into the analogical mapping process. We identify two variants on this “attribute matching” extension, which is required to solve different types of geometric proportional analogy problems. In the second part of this paper we describe how we use the simpler of these algorithms to generate inferences in topographic maps. We detail the results of identifying a number of different structures on a sample topographic map.