# RBM-sausage calculation of tracking data This function approximates the RBM-sausage of tracking data and returns a list of geom_path objects of the boundary. ```r dw_track(x, y = NULL, eps, nps = 20000, sc = 100) ``` ## Arguments - `x, y`: The `x` and `y` arguments provide the `x` and `y` coordinates of a set of points. Alternatively, a single argument `x` can be provided, see Details. - `eps`: Value of $\epsilon$. - `nps`: Number of points to generate in each segment connecting two locations, see Details. - `sc`: Scale factor. ## Details An attempt is made to interpret the arguments x and y in a way suitable for computing the RBM-sausage. Any reasonable way of defining the coordinates is acceptable, see `xy.coords`. Given a trajectory in the plane, the estimator is defined as the set of points whose distance to the trajectory is less than or equal to $\epsilon$ (this estimator is analogous to the one of Devroye and Wise (1980) for i.i.d. data). Increase `nps` if the trajectory is not contained in the computed estimator. ## Returns A list of geom_path objects defining the boundary of the estimator ## References Cholaquidis, A., Fraiman, R., Lugosi, G. and Pateiro-Lopez, B. (2014) Set estimation from reflected Brownian motion. **arXiv:1411.0433**. Devroye, L. and Wise, G. (1980) Detection of abnormal behaviour via nonparametric estimation of the support. **SIAM J. Appl. Math.** 3, pp. 480-488. Wikelski, M., and Kays, R. (2014). Movebank: archive, analysis and sharing of animal movement data. World Wide Web electronic publication. ## Examples ```r ## Not run: library(move) library(ggmap) # Data from Movebank # Study Name: Dunn Ranch Bison Tracking Project # Principal Investigator: Stephen Blake, Randy Arndt, Doug Ladd # Max Planck Institute for Ornithology Radolfzell Germany study <- "Dunn Ranch Bison Tracking Project" cainfo <- system.file("CurlSSL", "cacert.pem", package = "RCurl") options(RCurlOptions = list(verbose = FALSE, capath = cainfo, ssl.verifypeer = FALSE)) # Login to movebank (first create the login object) curl <- movebankLogin(username = "xxx", password = "zzz") # Downloads study stored in Movebank track <- getMovebankData(study = study, login = curl) dat <- track@data[track@data[, "deployment_id"] == 13848432,] # Map of animal locations bbox <- ggmap::make_bbox(dat[,"location_long"], dat[,"location_lat"], f = 0.3) map_loc <- get_map(location = bbox, source = "google", maptype = 'satellite') map <- ggmap(map_loc, extent = 'panel', maprange=FALSE) p <- map + geom_path(data = dat, aes(x = location_long, y = location_lat), col=2, size=0.3) p ah_dw <- dw_track(x = dat[, c("location_long", "location_lat")], eps = 0.001) p + ah_dw ## End(Not run) ```

dw_track function