node_coordinates: Query node coordinates

In luukvdmeer/sfnetworks: Tidy Geospatial Networks

Query node coordinates

Description

These functions allow to query specific coordinate values from the geometries of the nodes.

Usage

node_X()

node_Y()

node_Z()

node_M()

Details

Just as with all query functions in tidygraph, these functions are meant to be called inside tidygraph verbs such as mutate or filter, where the network that is currently being worked on is known and thus not needed as an argument to the function. If you want to use an algorithm outside of the tidygraph framework you can use with_graph to set the context temporarily while the algorithm is being evaluated.

Value

A numeric vector of the same length as the number of nodes in the network.

Note

If a requested coordinate value is not available for a node, NA will be returned.

Examples

library(sf, quietly = TRUE)
library(tidygraph, quietly = TRUE)

# Create a network.
net = as_sfnetwork(roxel)

# Use query function in a filter call.
filtered = net |>
  activate(nodes) |>
  filter(node_X() > 7.54)

oldpar = par(no.readonly = TRUE)
par(mar = c(1,1,1,1))
plot(net, col = "grey")
plot(filtered, col = "red", add = TRUE)
par(oldpar)

# Use query function in a mutate call.
net |>
  activate(nodes) |>
  mutate(X = node_X(), Y = node_Y())

# Use query function directly.
X = with_graph(net, node_X())
head(X)

luukvdmeer/sfnetworks documentation built on Nov. 21, 2024, 4:54 a.m.