bufferPoints: Make buffer around occurrence points

In peterbat1/fitMaxnet: Fit MaxEnt Niche Models Using maxnet

Make buffer around occurrence points

Description

Produce an sf polygon object representing the boundary within which background points will be sampled for ENM fitting

Usage

bufferPoints(occ_pts, bufferDist_km = 200, trace = FALSE)

Arguments

occ_pts	An sf points object providing the X- and Y-coordinates of occurrence records
bufferDist_km	Numeric. Size of buffer to be built around the occurrence points in kilometres. Default value of 200 km follows the advice of VanDerWal et al. (2009). See details below.
trace	Logical. Should messages be emitted to assist progress tracking or debugging

Details

bufferPoints() implements the widely used simple circular buffering approach introduced to niche modelling by VanDerWal et al. 2009. 'Selecting pseudo-absence data for presence-only distribution modeling: How far should you stray from what you know?' Ecological Modelling 220:589–594. The default value of 200 km for the buffer distance is the value recommended by VanDerWal et al. (2009) for a range of taxa which they considered in their paper. Naturally, the value to be used is a matter for consideration by the user. If there is a clear indication from available information regarding a taxon's mode of dispersal, or there is guidance from population genetics data, then another value might be supplied for this parameter. This implementation uses the spatial processing resources provided by the packages sp, sf and rgeos to achieve good performance and accurate handling of spatial data.

Value

An sf polygon object from the package sf

Note

Currently, this function can only process occurrence data from the Australian continent. Providing global coverage is feasible and will be implemented shortly for the OzWeeds project.

The function outputs a simple features ('sf') polygon object on the same projection which was inferred when occ_pts was parsed. That is, either EPSG:4326 (WGS84) if 'longitude' and 'latitude' column names were found, or EPSG:3577 (Australian ALber's Equal Area) if 'X' and 'Y' column names were found. If you need to use the buffer polygon on other projections, please re-project the returned object using, say, st_transform() from the package sf.

peterbat1/fitMaxnet documentation built on Sept. 17, 2024, 10:50 p.m.