Build linestrings from coordinate columns

Returns one linestring per run of linestring_id, through its rows in order.

Usage

ga_linestring(x, y, z = NULL, m = NULL, linestring_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

linestring_id

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

crs

a coordinate reference system to record, or NULL for none

Value

a GeoArrow linestring array with one element per linestring

Details

ga_linestring() matches sfheaders::sf_linestring(), taking the columns themselves rather than a data frame and their names. It reads the rows in order, so you must keep the rows of each linestring together: ga_linestring() errors when a linestring_id returns after a different one, and orders the linestrings by where each id first appears.

ga_linestring() 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_make_envelope(), ga_make_grid(), ga_make_line(), ga_make_line_agg(), ga_make_polygon(), ga_multilinestring(), ga_multipoint(), ga_multipolygon(), ga_point(), ga_polygon()

Examples

lines <- ga_linestring(
  c(0, 1, 2, 10, 11),
  c(0, 1, 0, 5, 5),
  linestring_id = c(1, 1, 1, 2, 2)
)
sf::st_as_sfc(geoarrow::as_geoarrow_vctr(lines))
#> Geometry set for 2 features 
#> Geometry type: LINESTRING
#> Dimension:     XY
#> Bounding box:  xmin: 0 ymin: 0 xmax: 11 ymax: 5
#> CRS:           NA
#> LINESTRING (0 0, 1 1, 2 0)
#> LINESTRING (10 5, 11 5)