Extract local climate for one or more locations for a given time slice.Source:
This function extract local climate for a set of locations at the appropriate times (selecting the closest time slice available for the specific date associated with each location).
location_slice( x, time_bp = NULL, time_ce = NULL, coords = NULL, bio_variables, dataset, path_to_nc = NULL, nn_interpol = TRUE, buffer = FALSE, directions = 8 )
a data.frame with columns x and y coordinates(see
coordsfor standard coordinate names, or how to use custom ones), plus optional columns
time_ce(depending on the units used) and
name. Alternatively, a vector of cell numbers.
used if no
time_bpcolumn is present in
x: the dates in years before present (negative values represent time before present, i.e. 1950, positive values time in the future) for each location.
time in years CE as an alternative to
time_bp.Only one of
time_ceshould be used.
a vector of length two giving the names of the "x" and "y" coordinates, as found in
data. If left to NULL, the function will try to guess the columns based on standard names
c("longitude", "latitude"), or
vector of names of variables to be extracted.
string defining the dataset to use. If set to "custom", then a single nc file is used from "path_to_nc"
the path to the custom nc file containing the palaeoclimate reconstructions. All the variables of interest need to be included in this file.
boolean determining whether nearest neighbour interpolation is used to estimate climate for cells that lack such information (i.e. they are under water or ice). By default, interpolation is only performed from the first ring of nearest neighbours; if climate is not available, NA will be returned for that location. The number of neighbours can be changed with the argument
nn_interpoldefaults to TRUE.
boolean determining whether the variable will be returned as the mean of a buffer around the focal cell. If set to TRUE, it overrides
nn_interpol(which provides the same estimates as
bufferbut only for locations that are in cells with an NA). The buffer size is determined by the argument
bufferdefaults to FALSE.
character or matrix to indicate the directions in which cells are considered connected when using
buffer. The following character values are allowed: "rook" or "4" for the horizontal and vertical neighbours; "bishop" to get the diagonal neighbours; "queen" or "8" to get the vertical, horizontal and diagonal neighbours; or "16" for knight and one-cell queen move neighbours. If directions is a matrix it should have odd dimensions and have logical (or 0, 1) values.