Visualization of Multivariate Data on Surfaces

In several domains of science and applications, the understanding of scientific data leads to technological advances and scientific discovery. Multivariate 3D data, for example, is essential for decision-making in fields such as Medicine and Geology, where experts are required to understand and correlate several spatial attributes. To simplify complexity and facilitate understanding, the 3D data is often explored through surfaces of interest. This is the reason why the visualization of multivariate data on surfaces has been a topic of interest among the visualization community. However, much work has been needed to provide visualization solutions that facilitate the multivariate visualization design, creation, and exploration. This research builds upon ideas introduced and discussed many years ago that focus on the problem of visualizing multiple attributes on surfaces in a single view. Here I present a new perspective to this problem as well as a solution that allows us to design, visualize and interact with multivariate data on surfaces. This perspective is created from the combination of several aspects born in fields such as Illustration, Perception, and Design, that have been employed and studied by the visualization community both in Information and Scientific Visualization. Therefore, this thesis lies between these two main fields, since it involves aspects from both. By building upon this multidisciplinary combination, I present a new way to visualize multivariate data on surfaces by exploiting the concept of layering. First, I introduce a new real-time rendering technique and the concept of Decal-Maps, which fills a gap in the literature and allow us to create 2D visual representations such as glyphs that follow the surface geometry. Building on this technique, I propose the layering framework to facilitate the multivariate visualization design on surfaces. The use of this concept and framework allows us to connect and generalize concepts established in flat space, such as 2D maps, to arbitrary surfaces. This thesis also demonstrates that the design of new multivariate visualizations on surfaces opens up other new possibilities such as the use of interaction techniques. Here I demonstrate this potential by introducing a new interaction technique that allows us to explore multivariate data and to create customized focus+context visualizations on surfaces. This is achieved by introducing a new category of lenses, Decal-Lenses, which extends the concept of magic-lenses from flat space to general surfaces. Finally, this thesis showcases the process of multivariate visual design and data exploration through a series of examples from several domains. Inspired by these examples, I also contribute with an in-depth application research conducted from my long-term collaboration with domain experts in the fields of Geology and Reservoir Engineering. This application illustrates how the proposed approach can support and facilitate decision-making in the complex process of Geological Modelling.
Multivariate Visualization, Illustrative Visualization, Visual Design, Interaction Design, Real-time Rendering, Surfaces
Avelino Rocha, A. C. (2019). Visualization of Multivariate Data on Surfaces (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from