Bearing

class ollin.movement_analyzers.bearing.Analyzer(movement)

Bearing analyzer.

Bearing refers to the angle formed by the movement of an individual with respect to a reference direction. In this case the reference direction is east.

Hence if \(p(t_0) = (x_0, y_0)\) and \(p(t_1) = (x_1, y_1)\) is the position of an individual at times \(t_0\) and \(t_1\) then the bearing at time \(t_0\) is defined by:

\[b = \arctan\left(\frac{y_1 - y_0}{x_0 - x_1}\right)\]

analyze(movement)

Extract bearings from movement data.

Get the bearings of all individuals in movement data at every time step. Will result in an array of size [num_individuals, time_steps - 1] so that:

bearing = results[i, k]

Means that the i-th individual had a bearing of bearing at the k-th time step.

Parameters:movement (Movement) – Movement data to analyze Returns:results – Array of shape [num_individuals, time_steps - 1] containing the bearings of all individuals at every time step. Return type:array

plot(ax=None, figsize=(10, 10), num_individual=0, bins=20, width=None, cmap='Reds', alpha=0.8, log=True)

Plot distribution of bearing angles.

Parameters:

• ax (matplotlib.axes.Axes, optional) – Axes object in which to plot.
• figsize (tuple or list, optional) – Size of figure to create if no axes are provided.
• num_individual (int or tuple or list or array, optional) – Selection of individuals from which to draw bearing angle information. If num_individual=’all’, all information will be plotted.
• bins (int, optional) – Number of bins to use in histogram of bearing distribution. Defaults to 20.
• width (float, optional) – Width of bars in histogram. If none is given, width will be maximum possible before overlap.
• cmap (str, optional) – Colormap to use to assign colors to histogram bars. Defaults to ‘Reds’.
• alpha (float, optional) – Alpha value of plot. Defaults to 0.8.