rspUD: Randomised Shortest Path Utilization Distribution
In jedalong/wildlifeTG: Time Geograhic Analysis of Wildlife Telemetry Data

Description Usage Arguments Details Value References See Also

Calculate the utilization distribution of an animal based on randomised shortest paths between fixes.

1	rspUD(traj, r, theta, theta.col, timescale = FALSE)

`traj`	animal movement trajectory in the form of an `ltraj` object, see package `adehabitatLT`
`r`	a `RasterLayer` object describing the preference/affinity of the landscape. May be the result of a resource selection function, or other analyses. Note: Higher values should be associated higher affinity.
`theta`	a global value for theta.
`theta.col`	character string of the name of the column containing values of theta for each segment (only used if theta is not provided).
`timescale`	(logical) whether or not to scale each segment so the sum of the output surface is equal to the duration of the segment (in seconds). Default = FALSE.

A randomised shortest path model is fit between every pair of fixes. The randomised shortest path model is derived from the passage function in the package gdistance. It uses the net number of packages (see ?passage) to estimate the probability and then scales the values appropriately. An input rasterLayer object is required which defines the ability for movement through the landscape, which might typically be derived from a resource selection function, or be related to known barriers on the landscape. It requires only a single parameter theta which can be estimated from the data using the function esttheta.

This function returns a RasterLayer which can be used to estimate the UD of an animal.

Long, J.A. Estimating wildlife utilization distributions using randomized shortest paths. (in Preparation)

esttheta, volras

jedalong/wildlifeTG documentation built on July 17, 2019, 2:52 p.m.