The recurse package has a new feature: the ability to examine revisits or residence time in convex polygons, rather than simply specifying a radius. This function came about due to conversations with Lacey Hughey, who I met at an AniMove course. She needed to calculate residence time for elk in a number of ranches. Simply approximating the residence time inside a circle wasn’t precise enough, so I implemented a function to calculate recursions and residence time inside a user-specified polygon that allowed her to use the specific ranch boundaries.

This function could be useful if there is a specific landscape feature where the precise boundary is important, such as a protected area, land use type, or animal’s territory. It could also be used to examine revisits to foraging areas where specific patch boundaries can be specified. There are some restrictions with the functions: the polygon must be convex (that is, any point on a line drawn from one point in the polygon to another point in the polygon will be inside the polygon) and only a one polygon at a time may be analyzed. Check out the new getRecursionsInPolygon function and the example in the vignette.

Reference: Bracis, C., Bildstein, K. L. and Mueller, T. (2018). Revisitation analysis uncovers spatio‐temporal patterns in animal movement data. Ecography. doi:10.1111/ecog.03618.

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