landscape.windows.random: Landscape windows: random method

In tleboucher/landscape.windows: Landscape windows functions

Description

This function creates landscape windows into an area defined by a shapefile (shape format) using the 'random method'. n windows are placed randomly in the defined area. With default values, to be validated, a window must contain at least 25 sites distributed over at least 80 percents of the window<e2><80><99>s area (at least 1 site in 8 cells of a 3 x 3 grid).

Usage

landscape.windows.random(data, shape.path, proj, windows, scales,
  min.no.sites = 25, area = 80, nrowcol = 3, plot = FALSE)

Arguments

data	Informations about sites (spatial coordinates). 'data' must have 3 columns: site ID, x and y.
shape.path	Absolute path to the shapefile (study area).
proj	Projection system. 'proj' must be expressed in EPSG code or in CRS.
windows	Informations about the desired number of windows. 'windows' must contain 2 values: the desired number of windows per scale and the number of attempts (should be a multiplicative factor to multiply the desired number of windows).
scales	Spatial scales to test. 'scales' must contain 3 values: the minimum windows' size, the maximum windows' size and the gap/break between two scales (in kilometers).
min.no.sites	Minimum number of sites in each window (default = 25).
area	Minimum percentage for the sites distributed over the window<e2><80><99>s area to ensure equal sampling effort across categories (default = 80).
nrowcol	Area is calculated with a grid of n rows/cols. 'nrowcol' determines n value (default = 3).
plot	TRUE or FALSE. Creation of a map of the study area with the centers of the validated windows (default = FALSE).

Value

Output data is a list of 3 objects: a table containing all the validated windows, for each scale, with a list of sites present in each window; a SpatialPointsDataFrame containing the data (sites); and a SpatialPolygon of the study area.

tleboucher/landscape.windows documentation built on May 28, 2019, 7:36 a.m.