An Assessment of Visual Variables for the Cartographic Design of 3D Informal Settlement Models
1Rautenbach, V.; 2Coetzee, S.; 3Schiewe, J.; 4Coltekin, A.
1UNIVERSITY OF PRETORIA Email: firstname.lastname@example.org
2UNIVERSITY OF PRETORIA Email: email@example.com
3HAFENCITY UNIVERSITY HAMBURG Email: firstname.lastname@example.org
4UNIVERSITY OF ZURICH Email: email@example.com
Visual variables were originally proposed for hard copy maps printed in black and white by Bertin in 1980s. However, we can now generate various digital geovisualization products that are inherently different from printed maps, such as interactive 3D city models. Additional visual variables have been proposed for some of these new geovisualizations, however the discussion is still on-going. In this paper, we contribute to this discussion by investigating the relevance of a subset of visual variables for planning informal settlement upgrades in 3D geovisualizations, and specifically how these variables contribute to the selectiveness of objects. The variables were systematically evaluated against specific requirements for planning upgrades which were compiled using expert knowledge. We observe that evaluated visual variables, except colour and texture, are not directly transferrable. Furthermore, we propose that; in an interactive 3D setting, visual variables position, orientation and motion should not be only considered in relation to the objects in a 3D environment, but also in relation to the camera, and the concept of Level of Detail (LoD) should replace shape. The results contribute towards building design principles of 3D informal settlement models for planning upgrades.