5

I try to draw a graph in map with R

code :

df<-data.frame("from" = c("Lyon", "Toulouse", "Paris", "Marseille"), 
               "to"= c("Paris", "Paris", "Marseille", "Toulouse"))
meta <- data.frame("name"=c("Lyon", "Toulouse", "Paris", "Marseille"), 
                   "lon"=c(-4.850000, 1.444209, 2.352222, 5.36978),  
                   "lat"=c(45.750000, 43.604652, 48.856614, 43.296482))

g <- graph.data.frame(df, directed=FALSE, vertices=meta)
lo <- layout.norm(as.matrix(meta[,2:3]))
plot.igraph(g, layout=lo,vertex.size = 60,
            vertex.color="red",
            vertex.frame.color= "white",
            vertex.label.color = "white",
            vertex.label.family = "sans",
            edge.width=2,  
            edge.color="black")

but I do not find a way that allows me to display it on the map using leaflet, someone has an idea please?

10

Here is one possible way, by first converting your graph to spatial object and using plotting these with with the leaflet package.

library(sp)
gg <- get.data.frame(g, "both")
vert <- gg$vertices
coordinates(vert) <- ~lon+lat

edges <- gg$edges

edges <- lapply(1:nrow(edges), function(i) {
  as(rbind(vert[vert$name == edges[i, "from"], ], 
           vert[vert$name == edges[i, "to"], ]), 
     "SpatialLines")
})


for (i in seq_along(edges)) {
  edges[[i]] <- spChFIDs(edges[[i]], as.character(i))
}

edges <- do.call(rbind, edges)


library(leaflet)
leaflet(vert) %>% addTiles() %>% addMarkers(data = vert) %>% addPolylines(data = edges)

enter image description here

You may want to improve the styling.

  • +1, thank you so much this is what I looking for , and if we want to draw the dotted line, how make it? – zina_GIS Dec 4 '15 at 13:20
  • 2
    @zina_GIS: have a look at ?leaflet::addPolylines and in particular at the dashArray argument. – johannes Dec 4 '15 at 13:23
  • exactly it's work with dashArray option thanks again – zina_GIS Dec 4 '15 at 13:34

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