sf_to_spm {smile}

single sf to spm

Description

Transforming a sf into a spm object (Internal use)

Usage

single_sf_to_spm(
  sf_obj,
  n_pts,
  type = "regular",
  by_polygon = FALSE,
  poly_ids = NULL,
  var_ids = NULL,
  trunc_d = NULL
)

sf_to_spm(
  sf_obj,
  n_pts,
  type = "regular",
  by_polygon = FALSE,
  poly_ids = NULL,
  var_ids = NULL,
  trunc_d = NULL
)

Arguments

sf_obj

a sf object s.t. its geometries are polygons.

n_pts

a numeric scalar representing the number of points to create a grid in the study region on which the polygons in sf_obj is observed. Alternatively, it can be a vector of the same length as nrow(sf_obj). In this case, it generates the given number of points for each polygon in sf_obj.

type

a character indicating the type of grid to be generated. The options are c("random", "regular", "hexagonal"). For more details, see st_sample in the sf package.

by_polygon

a logical indicating whether we should generate n_pts by polygon or for the n_pts for the whole study region.

poly_ids

a character vector informing the name of the variable in sf_obj that represents the polygons unique identifiers. In case this is not informed, we assume the id of the polygons are given by their row numbers.

var_ids

a scalar or vector of type character indicating the (numerical) variables that are going to be analyzed.

trunc_d

truncation distance for grid points. Consider using half of the maximum distance between polygons

Value

a named list of size 6 belonging to the class spm. This list stores all the objects necessary to fit models using the fit_spm.

Examples

data(liv_lsoa) # loading the LSOA data

msoa_spm <- sf_to_spm(sf_obj = liv_msoa, n_pts = 1000,
                      type = "regular", by_polygon = FALSE,
                      poly_ids = "msoa11cd",
                      var_ids = "leb_est")