vl_locate: Get the nearest point on the road network

In valh: Interface Between R and the OpenStreetMap-Based Routing Service Valhalla

Get the nearest point on the road network

Description

This function interfaces with the locate Valhalla service.

Usage

vl_locate(
  loc,
  verbose = FALSE,
  costing = "auto",
  costing_options = list(),
  server = getOption("valh.server")
)

Arguments

loc	one (or multiples) point(s) to snap to the street network. loc can be: a vector of coordinates (longitude and latitude, WGS 84), a data.frame of longitudes and latitudes (WGS 84), a matrix of longitudes and latitudes (WGS 84), an sfc object of type POINT, an sf object of type POINT.
verbose	logical indicating whether to return additional information.
costing	costing model to use.
costing_options	list of options to use with the costing model (see https://valhalla.github.io/valhalla/api/turn-by-turn/api-reference/#costing-options for more details about the options available for each costing model).
server	URL of the Valhalla server.

Value

If there is only one input point, return a single sf object containing the nearest point(s) on the road network. If there is more than one input point, return a list of sf objects, one for each input point.

Examples

## Not run: 
# Inputs are data frames
apotheke.df <- read.csv(system.file("csv/apotheke.csv", package = "valh"))

loc <- apotheke.df[1, c("lon", "lat")]

# Ask for the nearest point on the road network at this point
# using "auto" costing model
on_road_1 <- vl_locate(loc = loc)

# Inputs are sf points
library(sf)
apotheke.sf <- st_read(system.file("gpkg/apotheke.gpkg", package = "valh"),
  quiet = TRUE
)

# Ask for one point
locsf1 <- apotheke.sf[1, ]
# The result is a single sf object
on_road_2 <- vl_locate(loc = locsf1)

# Ask for multiple points
locsf2 <- apotheke.sf[1:3, ]
# The result is a list of sf objects
on_road_3 <- vl_locate(loc = locsf2)

## End(Not run)

valh documentation built on April 11, 2025, 6:14 p.m.