Visualisation of Sensor Data from Animal Movement

Abstract

A new area of biological research is identifying and grouping patterns of behaviour in wild animals by analysing data obtained through the attachment of tri-axial accelerometers. As these recording devices become smaller and less expensive their use has increased. Currently acceleration data are visualised as 2D time series plots, and analyses are based on summary statistics and the application of Fourier transforms. We develop alternate visualisations of this data so as to analyse, explore and present new patterns of animal behaviour. Our visualisations include interactive spherical scatterplots, spherical histograms, clustering methods, and feature-based state diagrams of the data. We study the application of these visualisation methods to accelerometry data from animal movement. The reaction of biologists to these visualisations is also reported.

Technological innovation in archival tags used in seabird research

“…We may hope so. The future will determine whether the faster processors in computers will allow even programs like IGOR Pro to function rapidly enough with the increasingly larger datasets or whether we will have to revert to bespoke software written in a highly efficient computer language such as C++ (Grundy et al 2009). Finally, complex data require complex analysis, but that this can be greatly facilitated by software that visualizes the data in a revealing manner.…”

“…9. Screenshot of an output of a program (CRYSTAL BALL; Grundy et al 2009) to visualize changes in behaviour adopted by an imperial cormorant Phalacrocorax atriceps during multiple dives and resting periods at the surface between them. The lines on the outside of the globe indicate animal body angle (the horizontal axis bisecting the globe is the pitch while the vertical axis bisecting the globe is the roll) so that lines on the right hand side of the globe indicate head-down posture (e.g.…”

“…Finally, complex data require complex analysis, but that this can be greatly facilitated by software that visualizes the data in a revealing manner. Spherical scatter plots represent such an approach, and are the basis behind a program called CRYSTAL BALL (Grundy et al 2009), which translates the 3 acceleration axes into a graph that can display 6 or 7 dimensions so that they are all visible in one moving image (Fig. 9).…”

Visualization of Vessel Traffic

“…These accumulation maps can also be used as the height in a 3D polyline rendering of trajectories as shown in Figure 2.7. World-wide trajectories and their aggregating 2D histograms are displayed by Grundy et al [63] in a special version of the space-time cube where the cube is folded around the globe. A more accurate approximation for density is given by Lampe and Hauser [95] who convolve trajectory segments with a constant speed to show the intensity of vessel traffic (see Fig.…”

Angular Histograms: Frequency-Based Visualizations for Large, High Dimensional Data

“…In this section, we use real world animal tracking data for some of our demonstrations [9]. Biologists at Swansea university have collected large amounts of data relating to animal movement by attaching sensors to individual subjects.…”