calculate.areas: Makes a social network based on the xy spatial coordinates provided.

Description

This method uses the area of the intersection between the territorial zones or home bases between each pair of individuals. For a spatial point pattern X, the association of individual j on individual i, Aij, is calculated as the percentage of the overlap of the discs centered at points X_i and X_j of the total area of the territorial area for individual i. The radius for each disc is the inputted interaction radius. The interaction radius for a given population can be identical for each individual, or different. The interaction radius represents the area within which an individual extracts nutrients or exerts its influence, or communicates an action.

The associations calcuated using this method can be asymmetric. In this case, the interaction radii for two given individuals would be different, implying that the proportion of the overlap between the zones for the individuals is different for each individual. As as example, Figure 1 illustrates the effect of different interaction radii per individual. Individual i is represented by the filled square and individual j is represented by the filled circle. The percentage of the overlap between the two territorial zones in the total area of territorial zone i is larger than that in territorial j, suggesting that the effect of individual j on i is greater than that of i on j.

The calculations are done based on a Monte Carlo method.

asymmetry.jpeg

Usage

calculate.areas(arg1, arg2, arg3, numpts)

Arguments

arg1

x coordinates for individuals

arg2

y coordinates for individuals

arg3

interaction radii for each individual (they can all be equal)

numpts

number of Monte Carlo simulations #'