rangemap_buffer generates a distributional range for a given species by buffering provided occurrences using a defined distance. Optionally, representations of the species extent of occurrence (using convex hulls) and the area of occupancy according to the IUCN criteria can also be generated. Shapefiles can be saved in the working directory if it is needed.
rangemap_buffer(occurrences, buffer_distance = 100000, polygons = NULL,
extent_of_occurrence = TRUE, area_of_occupancy = TRUE,
final_projection = NULL, save_shp = FALSE, name,
overwrite = FALSE, verbose = TRUE)a data.frame containing geographic coordinates of species occurrences, columns must be: Species, Longitude, and Latitude. Geographic coordinates must be in decimal degrees (WGS84).
(numeric) distance, in meters, to be used for creating the buffer areas around occurrences, default = 100000.
(optional) a SpatialPolygons* object to clip buffer areas and
adjust the species range and other polygons to these limits. Projection must
be WGS84 (EPSG:4326). If NULL, the default, a simplified world map
will be used.
(logical) whether to obtain the extent of occurrence
of the species based on a simple convex hull polygon; default = TRUE.
(logical) whether to obtain the area of occupancy
of the species based on a simple grid of 4 km^2 resolution;
default = TRUE.
(character) string of projection arguments for
resulting Spatial objects. Arguments must be as in the PROJ.4 documentation.
See CRS-class for details. If NULL, the default,
projection used is WGS84 (EPSG:4326).
(logical) if TRUE, shapefiles of the species range,
occurrences, extent of occurrence, and area of occupancy will be written in
the working directory. Default = FALSE.
(character) valid if save_shp = TRUE. The name of
the shapefile to be exported. A suffix will be added to name depending
on the object, as follows: species extent of occurrence = "_extent_occ", area
of occupancy = "_area_occ", and occurrences = "_unique_records".
(logical) whether or not to overwrite previous results with
the same name. Default = FALSE.
(logical) whether or not to print messages about the process. Default = TRUE.
A sp_range object (S4) containing: (1) a data.frame with information about the species range, and Spatial objects of (2) unique occurrences, (3) species range, (4) extent of occurrence, and (5) area of occupancy.
If extent_of_occurrence and/or area_of_occupancy = FALSE,
the corresponding spatial objects in the resulting sp_range object will be
empty, an areas will have a value of 0.
All resulting Spatial objects in the results will be projected to the
final_projection. Areas are calculated in square kilometers using the
Lambert Azimuthal Equal Area projection, centered on the centroid of occurrence
points given as inputs.
# NOT RUN {
# getting the data
data("occ_p", package = "rangemap")
# buffer distance
dist <- 100000
buff_range <- rangemap_buffer(occurrences = occ_p, buffer_distance = dist)
summary(buff_range)
# }
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