Update routing vignette

vignettes/stplanr-routing.Rmd

@@ -35,12 +35,31 @@ piggyback::pb_upload("roads_iow.geojson")
 roads_iow = sf::read_sf("https://github.com/ropensci/stplanr/releases/download/0.3.1/roads_iow.geojson")
 ```
 
-# osrm
+# OSRM
+
+Routing services such as OpenStreetMap Routing Machine (OSRM) require an input network, usually from OSM.
+
+We will use the `osrm` package:
+
+```{r}
+library(osrm)
+```
+
+To get OSM data for the Isle of Wight, for example, you can run the following commands:
+
+```{r, eval=FALSE}
+remotes::install_github("itsleeds/geofabrik")
+library(geofabrik)
+iow = get_geofabrik(name = "Isle of Wight")
+f = gf_filename("Isle of Wight")
+file.copy(f, "iow.pbf")
+options(osrm.server = "http://0.0.0.0:5000/", osrm.profile = "driving")
+```
+
 
 ```{r, echo=FALSE, eval=FALSE}
 if(!file.exists("iow.pbf"))
   download.file("http://download.geofabrik.de/europe/great-britain/england/isle-of-wight-latest.osm.pbf", "iow.pbf")
-options(osrm.server = "http://0.0.0.0:5000/", osrm.profile = "driving")
 ```
 
 Then in bash run the following commands to make the [OSRM docker image](https://hub.docker.com/r/osrm/osrm-backend/) work for you.
@@ -55,27 +74,49 @@ curl "http://127.0.0.1:5000/route/v1/driving/13.388860,52.517037;13.385983,52.49
 
 Now we can do routing in R!
 
-```{r, eval=FALSE}
+On a single route:
+
+```{r}
 l = pct::wight_lines_30
 p = line2points(l)
-r = osrm::osrmRoute(src = p[1, ], dst = p[2, ], returnclass = "sf")
+r = osrm::osrmRoute(src = p[1, ], dst = p[2, ], returnclass = "sf", overview = "full")
 plot(r)
 ```
 
+And to find many routes via the `route()` function, resulting in something like the figure below.
+
+```{r, eval=FALSE}
+routes_osrm = route(l = l, route_fun = osrmRoute, returnclass = "sf", overview = "full")
+rnet_osrm = overline(routes_osrm, attrib = "bicycle")
+mapview::mapview(rnet_osrm, lwd = rnet_osrm$bicycle / 10)
+```
+
+```{r, eval=FALSE, echo=FALSE}
+system.time({
+  routes_osrm = route(l = l, route_fun = osrmRoute, returnclass = "sf", overview = "full")
+})
+30 / 0.9 # around 30 routes per second
+saveRDS(routes_osrm, "routes_osrm.Rds")
+piggyback::pb_upload("routes_osrm.Rds")
+```
+
+
+```{r, echo=FALSE}
+knitr::include_graphics("https://user-images.githubusercontent.com/1825120/86858225-2970df80-c0b8-11ea-8394-07f98f1c8e8a.png")
+```
+
 ```{r, eval=FALSE}
-route_osrm2 = function(l) {
-  p = line2points(l)
-  s = (1:nrow(l)) * 2 - 1
-  list_out = lapply(s, function(i) osrm::osrmRoute(p[i, ], dst = p[i + 1, ], returnclass = "sf"))
-  do.call(rbind, list_out)
-}
-routes_osrm = route_osrm2(l)
-plot(routes_osrm)
 # tidy up
-file.remove("iow.pbf")
+f = list.files(pattern = "iow")
+unlink(x = f, recursive = TRUE)
 ```
 
+Shut down the docker container.
 
 
+```{r, eval=FALSE, engine='zsh'}
+docker ps
+docker stop stupefied_hopper
+```