Aggregate geometries

Returns the geometry as a MULTI* geometry. If the geometry is already a MULTI*, it is returned unchanged.

st_multi(.geom, ...)

Arguments

.geom	A geometry or a set of geometries of class sfc to be grouped. The geometries are often aggregated using a dplyr::group_by() followed by a dplyr::summarise().
...	Unused.

Value

a single MULTI* geometry.

See also

Other make: st_makeline, st_makepoint, st_numpoints

Examples

library(tibble)
library(dplyr)

tibble(g = c("a", "a"), point = c(st_point(12, 21), st_point(21, 12))) %>%
  group_by(g) %>%
  summarise(multi = st_multi(point))
#> # A tibble: 1 x 2
#>   g                  multi
#>   <chr>       <MULTIPOINT>
#> 1 a     ((12 21), (21 12))