Generate sf objects (1)

First let’s start at a higher level: we already have a data object.

Conversion can then be done with st_as_sf().

Suppose we have a data frame with point coordinates, and we know that the CRS is EPSG:4326.

d <- tibble(
  place = c("London", "Paris", "Madrid", "Rome"),
  long = c(-0.118092, 2.349014, -3.703339, 12.496366),
  lat = c(51.509865, 48.864716, 40.416729, 41.902782),
  value = c(200, 300, 400, 500))
d

## # A tibble: 4 × 4
##   place    long   lat value
##   <chr>   <dbl> <dbl> <dbl>
## 1 London -0.118  51.5   200
## 2 Paris   2.35   48.9   300
## 3 Madrid -3.70   40.4   400
## 4 Rome   12.5    41.9   500