In this paper, we describe an approach to generate semantic descriptions of entities in city maps so that they can be presented through accessible interfaces. The solution we present processes bitmap images containing city map excerpts. Regions of interest in these images are extracted automatically based on colour information and subsequently their geometric properties are determined. The result of this process is a structured description of these regions based on the Geography Markup Language (GML), an XML based format for the description of GIS data. This description can later serve as an input to innovative presentations of spatial structures using haptic and auditory interfaces