Utilizing to_spatial_smooth on a directed network

[jucardwell]

I am facing an issue with removing pseudo nodes from a directed road network. I have a road dataset with a significant number of pseudo nodes at areas where road characteristics change (change of speed limit, number of lanes, etc.). I have implemented the instructions in this vignette (https://cran.r-project.org/web/packages/sfnetworks/vignettes/sfn02_preprocess_clean.html) to create a directed network with two-way and one-way streets.

However, a problem arises when I try to remove these pseudo nodes on this directed network. Since, in many situations, these pseudo nodes take place on a part of the network that has two edges (because it is a two-way street), even though this is not a true intersection, to_spatial_smooth does not remove them.

I have provided a simplified example below. Any suggestions on how to address this?

library(sfnetworks)
library(sf)
library(tidygraph)
library(tidyverse)
library(igraph)

p1 = st_point(c(7, 51))
p2 = st_point(c(7, 52))
p3 = st_point(c(8, 52))
p4 = st_point(c(7, 51.5))

l1 = st_sfc(st_linestring(c(p1, p4)))
l2 = st_sfc(st_linestring(c(p1, p3)))
l3 = st_sfc(st_linestring(c(p3, p2)))
l4 = st_sfc(st_linestring(c(p4, p2)))

edges = st_as_sf(c(l1, l2, l3, l4), crs = 4326)
edges$oneway = c(FALSE, FALSE, FALSE, FALSE)
edges

duplicates = edges[!edges$oneway, ]
reversed_duplicates = st_reverse(duplicates)

edges = rbind(edges, reversed_duplicates)
net = as_sfnetwork(edges)

edges <- st_as_sf(net, "edges")

smoothed = convert(net, to_spatial_smooth)

plot(smoothed)

[luukvdmeer]

Interesting, I had not thought about this. In principle, the smoothing does perform as expected (since the "non-intersection" node does have two incoming and two outgoing edges, and hence is correctly not detected as being a pseudo node). But I do see that in this case, with a network containing both oneway and two-way streets, it should in practice be treated as a pseudo node. I'll try to think of a flexible solution.

[jucardwell]

Great, thanks for your time!

[jucardwell]

Hi Luuk! Still working on this issue, and have been unsuccessful so far. Have you had any ideas?