Estimation of geographic ranges from occurrence data

Geographic range as a function of a set of coordinates or sample/site/cell membeships.

Usage

georange(x, lng = NULL, lat = NULL, loc = NULL, method = "co")

Arguments

x

(data.frame) Occurrence table containing the coordinates/locality memberships as variables.

lng

(character) The variable name of the longitudes, required for the "co", "mst" and "mgcd" methods.

lat

(character) The variable name of the latitudes, required for the "co", "mst" and "mgcd" methods.

loc

(character) The variable name of the locality entries: cells, site or samples, required for the "lo" method.

method

(character) Geographic range estimator method. Can take multiple entries (concatenating the results in a vector). The following methods are implemented: "co": coordinate-based occupancy, the number of different coordinate pairs; "lo": locality-based occupancy for sites, samples or geographic cells, number of different entries in a variable. "mst", the total length of a minimum spanning tree of the point cloud, based on the great circle distances between points (requires the 'vegan' and 'icosa' packages). "mgcd", maximum great-circle distance that can be measured in the point cloud (this version is limited to half the circumference of the equator, requires the 'icosa' package).

Value

A numeric vector with geographic ranges (multiple methods).

Details

Multiple estimators of geographic ranges are implemented based on coordinates or cell identifiers. The function outputs a vector of the results based on the calculation methods specified in methods.

Examples

data(corals)
# select a  taxon from a certain time slice
  bitax <- corals[corals$stg==69 & corals$genus=="Microsolena",]
  georange(bitax, lng="paleolng", lat="paleolat", method="co")
#> co 
#> 16