inEllipsoid: Determine if a point is inside or outside an ellipsoid

Determine if a point is inside or outside an ellipsoid.

inEllipsoid(centroid, eShape, env_data, level)

Arguments

centroid	A numeric vector of centroids for each environmental variable
eShape	Shape matrix of the ellipsoid (can be a covariance matrix or a minimum volume ellipsoid).
env_data	A data frame with the environmental training data.
level	Proportion of points to be included in the ellipsoids. This parameter is equivalent to the error (E) proposed by Peterson et al. (2008).

Value

A data.frame with 2 columns. The first "in_Ellipsoid" binary response with values 1 (inside the ellipsoid) and zeros (outside the ellipsoid); the second "mh_dist" Mahalanobis distance to centroid.

Examples

if (FALSE) {
# Bioclimatic layers path
wcpath <- list.files(system.file("extdata/bios",
                                package = "ntbox"),
                    pattern = ".tif$",full.names = TRUE)
# Bioclimatic layers
wc <- raster::stack(wcpath)
# Occurrence data for the giant hummingbird (Patagona gigas)
pg <- utils::read.csv(system.file("extdata/p_gigas.csv",
                                  package = "ntbox"))
# Environmental data
pg_env <- raster::extract(wc,pg[,c("longitude",
                                      "latitude")],
                             df=TRUE)
pg_env <- pg_env[,-1]

pg_ellip <- cov_center(pg_env,mve=TRUE,
                       level=0.95,
                       vars = c("bio05",
                                "bio06",
                                "bio12"))
# Environmental random data
env_rdata <- raster::sampleRandom(wc,1000)
inErdata <- inEllipsoid(env_data = env_rdata[,c("bio05",
                                                "bio06",
                                                "bio12")],
                        centroid = pg_ellip$centroid,
                        eShape=pg_ellip$covariance,
                        level = 0.99)

}