Collapse a list of geometries into a single array

The inverse of ga_explode(). Concatenates every element's parts into one array, turning a list of n elements holding m parts in total into an array of length m.

Usage

ga_flatten(x)

Arguments

x

a list array of GeoArrow arrays, as ga_explode() returns

Value

a GeoArrow array holding every part, flattened

Details

ga_flatten() adds nothing for null elements, so it returns a different number of rows than the input whenever an element holds more or fewer than one geometry.

See also

Other cast: ga_as_point(), ga_cast_geometry(), ga_collection_extract(), ga_downcast_geometry(), ga_explode(), ga_from_wkb()

Examples

fp <- system.file("shape/nc.shp", package = "sf")
nc <- as.data.frame(read_shapefile(fp))

# 100 counties in, one row per polygon part out
length(nc$geometry)
#> [1] 100
ga_flatten(ga_explode(nc$geometry))$length
#> [1] 108