Build rectangles from their bounds

Returns the axis aligned rectangle spanning xmin to xmax and ymin to ymax on each row, as a polygon array. ga_make_envelope() recycles any bound of length 1.

Usage

ga_make_envelope(xmin, ymin, xmax, ymax, crs = NULL)

Arguments

xmin, ymin, xmax, ymax

numeric vectors or float64 arrays of the bounds; each length 1 or the same length as the longest

crs

a coordinate reference system to record, or NULL for none

Value

a GeoArrow polygon array

Details

This matches PostGIS ST_MakeEnvelope(). ga_make_envelope() sorts each pair of bounds, so a row with xmin above xmax gives the same rectangle. It returns a null polygon for a row where any bound is NA, so the result always has the same length as the longest bound.

ga_make_envelope() stores crs verbatim in the array's GeoArrow metadata and never interprets it. If you leave it NULL, it produces an array with no CRS.

See also

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

Examples

boxes <- ga_make_envelope(c(0, 10), c(0, 10), c(1, 12), c(2, 14))
sf::st_as_sfc(geoarrow::as_geoarrow_vctr(boxes))
#> Geometry set for 2 features 
#> Geometry type: POLYGON
#> Dimension:     XY
#> Bounding box:  xmin: 0 ymin: 0 xmax: 12 ymax: 14
#> CRS:           NA
#> POLYGON ((1 0, 1 2, 0 2, 0 0, 1 0))
#> POLYGON ((12 10, 12 14, 10 14, 10 10, 12 10))

as.vector(ga_unsigned_area(boxes))
#> [1] 2 8