Make 'nb' objects from sf objects

These functions can be used for geographic or projected coordinate reference systems and expect 2D data.

Usage

ww_build_neighbors(data, nb = NULL, ..., call = rlang::caller_env())

Arguments

data

An sf object (of class "sf" or "sfc").

nb

An object of class "nb" (in which case it will be returned unchanged), or a function to create an object of class "nb" from data and ..., or NULL. See details.

...

Arguments passed to the neighbor-creating function.

call

The execution environment of a currently running function, e.g. call = caller_env(). The corresponding function call is retrieved and mentioned in error messages as the source of the error.

You only need to supply call when throwing a condition from a helper function which wouldn't be relevant to mention in the message.

Can also be NULL or a defused function call to respectively not display any call or hard-code a code to display.

For more information about error calls, see Including function calls in error messages.

Value

An object of class "nb".

Details

When nb = NULL, the method used to create neighbors from data is dependent on what geometry type data is:

• If nb = NULL and data is a point geometry (classes "sfc_POINT" or "sfc_MULTIPOINT") the "nb" object will be created using ww_make_point_neighbors().

• If nb = NULL and data is a polygon geometry (classes "sfc_POLYGON" or "sfc_MULTIPOLYGON") the "nb" object will be created using ww_make_polygon_neighbors().

• If nb = NULL and data is any other geometry type, the "nb" object will be created using the centroids of the data as points, with a warning.

Examples

ww_build_neighbors(guerry)
#> Neighbour list object:
#> Number of regions: 85 
#> Number of nonzero links: 420 
#> Percentage nonzero weights: 5.813149 
#> Average number of links: 4.941176