Spherical Network Visualizations

Data visualization is a recent domain that founds his roots in the eighties, but its history dates back to more ancient times in other representations such as diagrams, drawings, or maps. In particular, data visualization is hard to take advantage of the heritage offered by cartography, a discipline with established theoretical and mathematical theories. Over more than two thousand years, cartography stimulated a discussion between critical thinking and spatial projections, with a keen interest for orientation and decision-making. This article picks up the cartographic technique of globe projection to apply it to network visualization. If the primary interest of globe projection in cartography is the flattened representation of the earth, in data visualization the focus is moved to the space continuity. In world maps usually the left and right sides are connected, the gaze can follow a trajectory that goes on the opposite side; while in data visualization the space of drawing is framed in all directions. Network visualizations rely on a relational logic applied on a limited flatland. We guess that drawing networks in a non-continuous space is a habit that can be changed. The hypothesis that drawing networks are less reductive on a spherical surface is supported by an example of travel distances between cities, which is mapped in two and three dimensions. Lastly, we argue that adopting a spherical projection eliminates the bias given by centrality in favor of spatial measure based on density.