Eurographics / IEEE Symposium on Visualization 2011 (EuroVis 2011) H. Hauser, H. Pfister, and J. J. van Wijk (Guest Editors) Volume 30 (2011), Number 3 The Undistort Lens John Brosz, Sheelagh Carpendale, and Miguel A. Nacenta Department of Computer Science, University of Calgary, Calgary, Alberta, Canada Abstract Detail-in-context lens techniques can be useful for exploring visualizations of data spaces that are too large or have too much detail to fit in regular displays. For example, by bending the space in the right way we can bring together details from two separate areas for easy comparison while roughly keeping the context that situates each area within the global space. While these techniques can be powerful tools, they also introduce distortions that need to be understood, and often the tools have to be disabled in order to have access to the undistorted data. We introduce the undistort lens, a complement to existing distortion-based techniques that provides a local and separate presentation of the original geometry without affecting any distortion-based lenses currently used in the presentation. The undistort lens is designed to allow interactive access to the underlying undistorted data within the context of the distorted space, and to enable a better understanding of the distortions. The paper describes the implementation of a generic back-mapping mechanism that enables the implementation of undistort lenses for arbitrary distortion based techniques, including those presented in the lens literature. We also provide a series of use-case scenarios that demonstrate the situations in which the technique can complement existing lenses. Categories and Subject Descriptors (according to ACM CCS): H. [H. Information Systems]: Information Interfaces and Presentation—H.5.2 User Interfaces 1. Introduction As our understanding of the possibilities and benefits of detail-in-context viewing improves, more variations con- tinue to arise. However, these information exploration tech- niques are still usually achieved through some type of dis- tortion and while the accompanying distortions may have become more sophisticated, they are also frequently com- plex. Into this interactive milieu, we introduce the undistort lens. The undistort lens is an interactive technique that pro- vides access to the undistorted data from within a distorted visualization. Consider the following scenario: we want to use a map (Fig. 1A) to find the best route between two distant small towns that are hundreds of miles from each other. This is a typical detail-in-context problem, since a map scale that al- lows us to recognize and see the towns (the detail) would be too big to fit on any screen, and a scale that makes the dis- tance between the towns fit within a reasonable space (the context) could make the towns invisible or indistinguishable from other similar objects. There are a number of visualiza- tion techniques based on distortion that can help us solve this problem. For example, magnification lenses can be placed on c  2011 The Author(s) Journal compilation c 2011 The Eurographics Association and Blackwell Publishing Ltd. Published by Blackwell Publishing, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main Street, Malden, MA 02148, USA.