Cast to the narrowest geometry type

Inspects the geometries and casts to the most specific type that can hold every one of them. A geometry array holding only points becomes a point array; one holding points and polygons is left alone, since no narrower type fits.

Usage

ga_downcast_geometry(x)

Arguments

x

a GeoArrow geometry array

Value

a GeoArrow array of the narrowest type that fits, the same length as x

Details

This is the inverse of casting up to geometry, and is useful after reading a format that does not record a single geometry type.

See also

Other cast: ga_as_point(), ga_cast_geometry(), ga_explode(), ga_flatten(), ga_from_wkb()

Examples

pts <- ga_xy(c(0, 1), c(0, 1))
wide <- ga_cast_geometry(pts, "geometry")

# only points in there, so it narrows back to a point array
ga_downcast_geometry(wide)
#> <nanoarrow_array geoarrow.point{struct}[2]>
#>  $ length    : int 2
#>  $ null_count: int 0
#>  $ offset    : int 0
#>  $ buffers   :List of 1
#>   ..$ :<nanoarrow_buffer validity<bool>[null] ``
#>  $ children  :List of 2
#>   ..$ x:<nanoarrow_array double[2]>
#>   .. ..$ length    : int 2
#>   .. ..$ null_count: int 0
#>   .. ..$ offset    : int 0
#>   .. ..$ buffers   :List of 2
#>   .. .. ..$ :<nanoarrow_buffer validity<bool>[null] ``
#>   .. .. ..$ :<nanoarrow_buffer data<double>[2][16 b]> `0 1`
#>   .. ..$ dictionary: NULL
#>   .. ..$ children  : list()
#>   ..$ y:<nanoarrow_array double[2]>
#>   .. ..$ length    : int 2
#>   .. ..$ null_count: int 0
#>   .. ..$ offset    : int 0
#>   .. ..$ buffers   :List of 2
#>   .. .. ..$ :<nanoarrow_buffer validity<bool>[null] ``
#>   .. .. ..$ :<nanoarrow_buffer data<double>[2][16 b]> `0 1`
#>   .. ..$ dictionary: NULL
#>   .. ..$ children  : list()
#>  $ dictionary: NULL