Split SpatVector by groups

group_split() works like base::split() but:

• It uses the grouping structure from group_by.SpatVector() and therefore is subject to the data mask.

• It does not name the elements of the list based on the grouping as this only works well for a single character grouping variable. Instead, use group_keys.SpatVector() to access a data frame that defines the groups.

See dplyr::group_split() for more information.

Usage

# S3 method for class 'SpatVector'
group_split(.tbl, ..., .keep = TRUE)

Arguments

.tbl

A SpatVector object. See Methods.

...

If .tbl is an ungrouped SpatVector, a grouping specification, forwarded to group_by.SpatVector().

.keep

Should the grouping columns be kept?

Value

A list of SpatVector objects. Each SpatVector contains the rows of .tbl for the associated group and all columns. When .keep = TRUE, the output includes the grouping variables.

Details

See Details on dplyr::group_split().

Lifecycle

group_split() is not stable because you can achieve very similar results by manipulating the nested column returned from nest(.by =). That also retains the group keys all within a single data structure. group_split() may be deprecated in the future.

terra equivalent

terra::svc().

Methods

Implementation of the generic dplyr::group_split() for SpatVector objects.

See also

dplyr::group_split(), terra::svc()

Other dplyr grouping methods: group_by.SpatVector(), group_map.SpatVector(), group_nest.SpatVector(), group_trim.SpatVector()

Examples

v <- terra::vect(system.file("extdata/cyl.gpkg", package = "tidyterra"))

v$group <- rep(c("A", "B", "C"), 3)

v |>
  group_by(group) |>
  group_split()
#> [[1]]
#> class       : SpatVector
#> geometry    : polygons
#> dimensions  : 3, 4  (geometries, attributes)
#> extent      : 2987054, 3341372, 2017622, 2330449  (xmin, xmax, ymin, ymax)
#> coord. ref. : ETRS89-extended / LAEA Europe (EPSG:3035)
#> names       :  iso2  cpro     name group
#> type        : <chr> <chr>    <chr> <chr>
#> values      : ES-AV    05    Avila     A
#>                ES-P    34 Palencia     A
#>               ES-SO    42    Soria     A
#> 
#> [[2]]
#> class       : SpatVector
#> geometry    : polygons
#> dimensions  : 3, 4  (geometries, attributes)
#> extent      : 2892687, 3296229, 2049224, 2331004  (xmin, xmax, ymin, ymax)
#> coord. ref. : ETRS89-extended / LAEA Europe (EPSG:3035)
#> names       :  iso2  cpro       name group
#> type        : <chr> <chr>      <chr> <chr>
#> values      : ES-BU    09     Burgos     B
#>               ES-SA    37  Salamanca     B
#>               ES-VA    47 Valladolid     B
#> 
#> [[3]]
#> class       : SpatVector
#> geometry    : polygons
#> dimensions  : 3, 4  (geometries, attributes)
#> extent      : 2920108, 3216695, 2063930, 2361600  (xmin, xmax, ymin, ymax)
#> coord. ref. : ETRS89-extended / LAEA Europe (EPSG:3035)
#> names       :  iso2  cpro    name group
#> type        : <chr> <chr>   <chr> <chr>
#> values      : ES-LE    24    Leon     C
#>               ES-SG    40 Segovia     C
#>               ES-ZA    49  Zamora     C
#> 

# Coerce the result to a SpatVectorCollection.
v |>
  group_by(group) |>
  group_split() |>
  terra::svc()
#>  class       : SpatVectorCollection
#>  length      : 3
#>  geometry    : polygons (3)
#>                polygons (3)
#>                polygons (3)
#>  crs (first) : ETRS89-extended / LAEA Europe (EPSG:3035)
#>  names       : , ,