Environmental contrasts between sites — site

At-site features: the value of each environmental layer at the source site minus its value at the destination site. Sites can be points (the cell value is used) or polygons (the area-weighted mean is used). Site-level attributes such as meadow area or network degree can be supplied as a data.frame instead of, or in addition to, rasters.

Usage

site_contrast(
  sites,
  pairs,
  env = NULL,
  attributes = NULL,
  id = "site",
  suffix = ".at"
)

Arguments

sites: An sf object of sites.
pairs: Data.frame with columns from and to (directed pairs).
env: Optional SpatRaster of environmental layers.
attributes: Optional data.frame with an ID column and one column per site attribute.
id: Name of the ID column in sites (and attributes).
suffix: Appended to the feature names.

Value

A data.frame with from, to and one column per feature, each equal to the source value minus the destination value.

Examples

ex <- corridor_example()
pr <- data.frame(from = c("M01", "M12"), to = c("M12", "M01"))
site_contrast(ex$sites, pr, env = ex$env[["snowpack"]])
#>     from  to snowpack.at
#> M01  M01 M12   -496.4841
#> M12  M12 M01    496.4841