Build multipoints from coordinate columns

Returns one multipoint per run of multipoint_id, holding its rows in order.

Usage

ga_multipoint(x, y, z = NULL, m = NULL, multipoint_id = NULL, crs = NULL)

Arguments

x, y

numeric vectors or float64 arrays of coordinates, one row per vertex

z, m

numeric vectors or float64 arrays of z and m values, or NULL to leave out that dimension

multipoint_id

a numeric vector, character vector, or Arrow array naming the multipoint of each row, or NULL for a single multipoint

crs

a coordinate reference system to record, or NULL for none

Value

a GeoArrow multipoint array with one element per multipoint

Details

ga_multipoint() matches sfheaders::sf_multipoint(), taking the columns themselves rather than a data frame and their names. You must keep the rows of each multipoint together: ga_multipoint() errors when a multipoint_id returns after a different one, and orders the multipoints by where each id first appears.

ga_multipoint() adds the z and m dimensions when you supply z and m. It errors on NA in any coordinate or id, and reuses the coordinate arrays without copying them.

See also

Other construct: ga_linestring(), ga_make_envelope(), ga_make_grid(), ga_make_line(), ga_make_line_agg(), ga_make_polygon(), ga_multilinestring(), ga_multipolygon(), ga_point(), ga_polygon()

Examples

pts <- ga_multipoint(c(0, 1, 5), c(0, 1, 5), multipoint_id = c("a", "a", "b"))
sf::st_as_sfc(geoarrow::as_geoarrow_vctr(pts))
#> Geometry set for 2 features 
#> Geometry type: MULTIPOINT
#> Dimension:     XY
#> Bounding box:  xmin: 0 ymin: 0 xmax: 5 ymax: 5
#> CRS:           NA
#> MULTIPOINT ((0 0), (1 1))
#> MULTIPOINT ((5 5))