1 Introduction Uncertainty refers to imperfect representations of the real world which include both verbal descriptions and visual representations such as sketch maps. This can take the form of inaccuracy, where elements are either added or removed leading to an erroneous representation or imprecision where the state of the real world and its semantics are not specific enough to represent [1]. In our study of uncertain places, we focus on the latter which could arise due to ambiguity (multiple definitions or possible interpretations) and vagueness (imprecise definition leads to borderline cases) [2]. Places that are uncertain, especially vague ones are hardly represented on metric maps, owing partly to the difficulty in visualizing them. But, people often use them in communicating about the environment [3] such as in giving wayfinding instructions. We also refer to these places to convey an idea of direction to take and for orientation purposes even though it may not be the destination. Sketch maps are a good source to elicit information about such places. The use of vague places in route descriptions both in verbal instructions and in sketch maps is not extensively explored in many studies. Hence, this paper attempts to fill this gap by providing insights of how such places are visualized based on people’s knowledge that was drawn on sketch maps. The following sections present the experiment design, results, discussion and conclusion in the broader scope of our ongoing research in wayfinding. 2 Experiment 2.1 Participants A total of 20 participants (11 males, 9 females) aged between 20 and 35 years (M = 27.7 years, SD = 4.3) took part in the experiment. The participants are mostly university students from various fields of study who have been living in the study area for a minimum of six months. The rest of the participants are university employees. They received 10€ as payment for participation. 2.2 Study Area The study area is in Muenster, a major city in Germany, which is also considered as a university town. 2.3 Design In the experiment, participants were assigned to either of the two groups (A and B) consisting of different tasks. Participants who received Experiment A were asked to draw a sketch map within a city route (from harbour to natural science campus) while Experiment B was a city to city route (from natural science campus in Muenster to any city in Germany). We identified uncertain places to be drawn in the sketch maps. These places are: city center, natural science campus, the university hospital, the castle, and the harbour (Hafen). Map-off the city: How uncertain places are represented in sketch maps Vanessa Joy A. Anacta Institute for Geoinformatics University of Muenster Heisenbergstrasse 2, 48149 Muenster, Germany v.anacta@uni-muenster.de Mohammed Imaduddin Humayun Institute for Geoinformatics University of Muenster Heisenbergstrasse 2, 48149 Muenster, Germany humayun@uni-muenster.de Angela Schwering Institute for Geoinformatics University of Muenster Heisenbergstrasse 2, 48149 Muenster, Germany schwering@uni-muenster.de Abstract The paper evaluates different visualization techniques for uncertain places in route sketch maps. Vague places, for instance, are often used in daily communication but there is a lack of extensive research on how to visualize them. In this study, we asked 20 participants to draw a specific route on the sketch maps with selected places in the city that have uncertain boundaries. A previously developed visualization classification scheme is used to categorize them. We found that participants usually combine labels with any bounded shape to represent uncertain places. This is followed by the use of a simple label to visualize the place in the sketch maps. The various classifications provide ideas of how uncertain places may be visualized and the results may be incorporated in designing better interfaces for various information systems. Keywords: uncertainty, route sketch maps, wayfinding, navigation, orientation.