“…Tracking data has been gathered on avatars moving in 2-D virtual space in games, virtual museums and VFTs, with various different techniques used to visualise the data (Börner & Penumarthy, 2003;Coulton et al, 2008;Oda et al, 2009;Sookhanaphibarn et al, 2011). Most pertinent for visualising our 4-D data, Chittaro and Ieronutti (2004) split the floor of a virtual museum into a grid of cells, recording the tracks of virtual visitors through the grid.…”