Closest point on a geometry

Returns the position on each geometry nearest the corresponding point, using planar distance. ga_closest_point_haversine() measures on a sphere instead, treating coordinates as longitude and latitude in degrees.

Usage

ga_closest_point(geometry, point)

ga_closest_point_haversine(geometry, point)

Arguments

geometry

a GeoArrow geometry array

point

a GeoArrow point array; length 1 or the same length as geometry

Value

a GeoArrow point array of the same length as geometry

Details

When the point lies on the geometry the intersection itself is returned. A geometry with no single nearest position, such as a point equidistant from both ends of a symmetric line, becomes a null element, as does a null geometry or a null point.

References

ClosestPoint

HaversineClosestPoint

See also

Other query: ga_interior_point(), ga_is_convex(), ga_line_locate_point()

Examples

line <- geoarrow::as_geoarrow_array(sf::st_sfc(
  sf::st_linestring(cbind(c(0, 10), c(0, 0)))
))
pt <- geoarrow::as_geoarrow_array(sf::st_sfc(sf::st_point(c(4, 5))))

sf::st_as_sfc(geoarrow::as_geoarrow_vctr(ga_closest_point(line, pt)))
#> Geometry set for 1 feature 
#> Geometry type: POINT
#> Dimension:     XY
#> Bounding box:  xmin: 4 ymin: 0 xmax: 4 ymax: 0
#> CRS:           NA
#> POINT (4 0)