Realizes predictions that can be useful when researchers are interested in predict a variable observed in one political division of a city (or state) on another division of the same region.

## Usage

predict_spm(x, ...)

# S3 method for spm_fit
predict_spm(x, .aggregate = TRUE, ...)

# S3 method for sf
predict_spm(x, spm_obj, n_pts, type, outer_poly = NULL, id_var, ...)

## Arguments

x

a sf object such that its geometris are either points or polygons.

...

.aggregate

logical. Should the predictions be aggregated? In case the input is only a "fit" object, the aggregation is made over the polygons on which the original data was observed. In case the input x is composed by sf POLYGONS, the aggregation is made over this new partition of the study region.

spm_obj

an object of either class spm_fit or mspm_fit

n_pts

a numeric scalar standing for number of points to form a grid over the whole region to make the predictions

type

character type of grid to be generated. See st_sample in the package sf.

outer_poly

(object) sf geometry storing the "outer map" we want to compute the predictions in.

id_var

if x is a set of POLYGONS (areal data) instead of a set of points, the id_var is the name (or index) of the unique identifier associated to each polygon.

## Value

a list of size 4 belonging to the class spm_pred. This list contains the predicted values and the mean and covariance matrix associated with the conditional distribution used to compute the predictions.

## Examples



msoa_spm <- sf_to_spm(sf_obj = liv_msoa, n_pts = 500,
type = "regular", by_polygon = FALSE,
poly_ids = "msoa11cd",
var_ids = "leb_est")
## fitting model
theta_st_msoa <- c("phi" = 1) # initial value for the range parameter

fit_msoa <-
fit_spm(x = msoa_spm,
theta_st = theta_st_msoa,
model = "matern",
nu = .5,
apply_exp  = TRUE,
opt_method = "L-BFGS-B",
control    = list(maxit = 500))

pred_lsoa <- predict_spm(x = liv_lsoa, spm_obj = fit_msoa, id_var = "lsoa11cd")
#> Warning: st_centroid assumes attributes are constant over geometries of x