ICA-Proc Proceedings of the ICA ICA-Proc Proc. Int. Cartogr. Assoc. 2570-2092 Copernicus Publications Göttingen, Germany 10.5194/ica-proc-4-66-2021 Effect of Geospatial Uncertainty Borderization on Users’ Heuristic Reasoning Libertini Lorenzo 1 Chuprikova Ekaterina 2 Meng Liqiu 3 International M.Sc. of Cartography, Chair of Cartography, Technical University of Munich, Germany Centre for Sensing Solutions, EURAC research Chair of Cartography, Department of Aerospace and Geodesy, Technical University of Munich, Germany 03 12 2021 4 66 Copyright: © 2021 Lorenzo Libertini et al. 2021 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://ica-proc.copernicus.org/articles/ica-proc-4-66-2021.html The full text article is available as a PDF file from https://ica-proc.copernicus.org/articles/ica-proc-4-66-2021.pdf

A set of mental strategies called "heuristics" – logical shortcuts that we use to make decisions under uncertainty – has become the subject of a growing number of studies. However, the process of heuristic reasoning about uncertain geospatial data remains relatively under-researched. With this study, we explored the relation between heuristics-driven decision-making and the visualization of geospatial data in states of uncertainty, with a specific focus on the visualization of borders, here termed "borderization". Therefore, we tested a set of cartographic techniques to visualize the boundaries of two types of natural hazards across a series of maps through a user survey. Respondents were asked to assess the safety and desirability of several housing locations potentially affected by air pollution or avalanches. Maps in the survey varied by "borderization" method, background color and type of information about uncertain data (e.g., extrinsic vs. intrinsic). Survey results, analyzed using a mixed quantitative-qualitative approach, confirmed previous suggestions that heuristics play a significant role in affecting users' map experience, and subsequent decision-making.