spnethack

The goal of spnethack is to explore spatial networks in R.

Requirements

We’ll use the following packages:

library(sf)
library(osmdata)
library(dodgr)
library(stplanr)
library(dplyr)
library(piggyback)
library(tidygraph)
library(sfnetworks)

Data

It makes sense to have some input data.

From josm

Data from OSM was downloaded with the josm GUI. It can be read-in as follows:

pb_download("promenade-all.geojson")
promenade_all = read_sf("promenade-all.geojson")
summary(factor(promenade_all$highway))
promenade_min = promenade_all %>% 
  filter(name == "Promenade")

summary(is_linestring)
promenade_way = promenade_all %>% 
  filter(!is.na(highway)) %>% 
  filter()
# write_sf(promenade_way, "promenade-way.geojson")
# write_sf(promenade_min, "promenade-min.geojson")

The minimum dataset can be read-in as follows:

pb_download("promenade-min.geojson")
#> ✔ Setting active project to '/home/robin/repos/spnethack'
#> All files up-to-date already
promenade_min = read_sf("promenade-min.geojson")
plot(promenade_min$geometry)

A slightly larger dataset can be read-in and plotted as follows:

pb_download("promenade-way.geojson")
#> All files up-to-date already
promenade_way = geojsonsf::geojson_sf("promenade-way.geojson")
plot(promenade_way$geometry)

summary(factor(st_geometry_type(promenade_way)))
#> LINESTRING 
#>       2020
is_point = st_geometry_type(promenade_way) == "POINT"
promenade_way = promenade_way[!is_point, ]
promenade_way = st_cast(promenade_way, "LINESTRING")

From osmdata

promenade_osmdata = opq(bbox = 'Muenster, DE') %>% 
  add_osm_feature(key = 'name', value = 'Promenade') %>% 
  osmdata_sf %>% 
  unique_osmdata()

From dodgr

muenster = dodgr_streetnet('Muenster, DE')
promenade_dodgr = muenster %>% filter(name == 'Promenade')

Route networks with stplanr

The code to create route network data is in stplanr-promenade.R. It can generate a ‘betweenness’ graph like this:

source(file = "stplanr-promenade.R")

Route networks with dodgr

An example of how to create route data from sample points along the edges can be found dodgr-promenade.R, it can also generate a flow aggregate which is quite similar to the betweenness.

source(file = "dodgr-promenade.R")
dodgr_flowmap(graph_f, linescale = 5)

To do this we can use all the points in the data 430 points on the to column and the same number on the from, and it takes 0.6 sec.

Route networks with sfnetworks

p_sfn = sfn_asnetwork(promenade_min)
plot(p_sfn)

p_graph = sfn_network2graph(p_sfn)
b = igraph::edge.betweenness(p_graph)
plot(p_sfn, lwd = b / mean(b))

Munster example

p_sfn = sfn_asnetwork(promenade_way)
plot(p_sfn)
i = sfn_network2graph(p_sfn)
b = igraph::edge.betweenness(i)
p_sfn$edges$b = b
plot(p_sfn, lwd = b / mean(b))

Route networks with spnetwork

Route networks with osmnx

Route networks with tidygraph

rtg = as_tbl_graph(x = rstp@g)
class(rtg)
#> [1] "tbl_graph" "igraph"
length(rtg)
#> [1] 10
rtg$geometry = promenade_min$geometry
plot(rtg)

plot(rtg$geometry)

# But fails with subsetting...
rtg_sub = rtg[1:5, ]
rtg_sub
#> 5 x 31 sparse Matrix of class "dgCMatrix"
#>                                                                   
#> [1,]   .      388.3444  .        .       .   .        .      . . .
#> [2,] 388.3444   .       .        .       .   .      663.5711 . . .
#> [3,]   .        .       .       25.28429 .   .        .      . . .
#> [4,]   .        .      25.28429  .       .   .        .      . . .
#> [5,]   .        .       .        .       . 155.1238   .      . . .
#>                                                                           
#> [1,] 6.592897 . . . . .  .       . . . . .  .       . . . . . .  .       .
#> [2,] .        . . . . .  .       . . . . .  .       . . . . . .  .       .
#> [3,] .        . . . . .  .       . . . . . 84.70141 . . . . . .  .       .
#> [4,] .        . . . . . 83.52986 . . . . .  .       . . . . . .  .       .
#> [5,] .        . . . . .  .       . . . . .  .       . . . . . . 87.09183 .

Converting tidygraph into sf objects

rtg_edges = activate(rtg,edges) %>% mutate(geometry = promenade_min$geometry)

st_as_sf(as.tibble(rtg_edges))

Benchmark

system.time({rnet1 = SpatialLinesNetwork(promenade_way)})
class(rnet1)
system.time({
  rnet2 = sfn_asnetwork(promenade_way)
  i = sfn_network2graph(rnet2)
})
object.size(rnet1)
object.size(rnet2)

luukvdmeer / spnethack