Match spatial points to the vertices of a spatial graph.

The match_pts_to_graph function matches points to the nearest edge based on geometric intersections; this function only matches to the nearest vertex based on point-to-point distances.

Usage

match_pts_to_verts(verts, xy, connected = FALSE)

Arguments

verts

A data.frame of vertices obtained from dodgr_vertices(graph).

xy

coordinates of points to be matched to the vertices, either as matrix or sf-formatted data.frame.

connected

Should points be matched to the same (largest) connected component of graph? If FALSE and these points are to be used for a dodgr routing routine (dodgr_dists, dodgr_paths, or dodgr_flows_aggregate), then results may not be returned if points are not part of the same connected component. On the other hand, forcing them to be part of the same connected component may decrease the spatial accuracy of matching.

Value

A vector index into verts

See also

Other match: add_nodes_to_graph(), match_points_to_graph(), match_points_to_verts(), match_pts_to_graph()

Examples

net <- weight_streetnet (hampi, wt_profile = "foot")
verts <- dodgr_vertices (net)
# Then generate some random points to match to graph
npts <- 10
xy <- data.frame (
    x = min (verts$x) + runif (npts) * diff (range (verts$x)),
    y = min (verts$y) + runif (npts) * diff (range (verts$y))
)
pts <- match_pts_to_verts (verts, xy)
pts # an index into verts
#>  [1] 3079 1704 1704 3077 2923 1704 3078 2921 3082 2343
pts <- verts$id [pts]
pts # names of those vertices
#>  [1] "1388482473" "2588119056" "2588119056" "6597298435" "2398957539"
#>  [6] "2588119056" "6597300510" "313796433"  "3921525779" "2398957612"