I. INTRODUCTION
Service robots or mobile robot companions need to navigate in an environment that they share with their users. They also have to be able to report their current state and whereabouts in a way that is comprehensible for the user. Robotic localization and mapping is most often performed using geometric features being derived from sensory measurements. Those feature based representations are typically different from the spatial models that humans use to define and reason about the same environment. This poses a challenge in particular if the system is to be operated by novice users without any robotics background.