I have a network created with igraph and then viewed with ggraph. The edges have different weights based on the data as do the nodes.
I want to place the network on a map according to the nodes gps coordinates, but I can't figure out how to transfer the igraph or ggraph onto a map/shapefile and how to retain the weights.
There are two datasets, one for edges and one for the vertices. Each vertex is a site. I want to keep the network weights and overlay it onto a map of the study site, but I can't figure out how to keep those weights in ggplot. I have seen that people make tables, but I tried and can't get the tables to retain the weight of the nodes and edges.
When I try to turn the network into an object, I get the following error:
Error in if (dim(x)[2] > 2) vals <- x[, -(1:2), drop = FALSE] else vals <- NULL : argument is of length zero
There have been a few posts asking a similar concept. From igraph to ggplot object how to plot a network on to a geographic map in R? Error converting igraph to network object in R
Appreciate any advice/direction.
library(igraph) library(ggraph) library(ggforce) library(ggmap) library(dplyr)
`
> edges.df
to from sum_code
1 B B 24
2 B C 1
3 B D 3
4 B G 9
5 B H 2
6 B J 3
7 C C 4
8 C G 6
9 C J 1
10 D D 16
11 D F 27
12 D G 1
13 D H 1
14 E F 3
15 F F 20
16 F G 2
17 F H 2
18 G G 230
19 G H 22
20 G I 4
21 H H 22
22 J J 109
> vertices.df
locations x y
1 A 46.20323 -9.390967
2 B 46.21088 -9.410898
3 C 46.22592 -9.403538
4 D 46.21906 -9.429763
5 E 46.22664 -9.419323
6 F 46.22702 -9.439434
7 G 46.23780 -9.438571
8 H 46.25050 -9.427436
9 I 46.23859 -9.449669
10 J 46.43900 -9.380025
`
`
g <- graph_from_data_frame(d = edges.df, vertices = vertices.df, directed = FALSE)
g
# get lat long coordinates for the layout
lo <- layout.norm(as.matrix(vertices.df[, c("x","y")]))
#plot
plot.igraph(g, layout=lo, rescale=T, vertex.label= NA)
plot(g)
str(g)
as_data_frame(g, what="edges")
as_data_frame(g, what="vertices")
net<- g
#compute node degrees (and links) and use it to set node size
deg <- degree(net, mode="all")
V(net)$size <- deg*4
# Set edge width based on weight:
E(net)$width <- E(net)$sum_code/6 # 6 is just a very arbitrary number chosen
#change arrow size and edge color:
E(net)$edge.color <- "gray80"
plot(net, vertex.color = "lightgrey")
#here i lose the weights of the nodes and of the loops
ggraph(net, layout="stress") +
geom_edge_link(color="lightgrey", aes(width=width)) +
geom_edge_loop(color="darkgrey",)+
scale_edge_width(aes(size=E(net)$width))+
geom_node_point(color="light blue",aes(size=V(net)$size))+
geom_node_text(aes(label = name))+
theme_void()
#try to turn it into a list using as.network but get error
as.network(net1, directed=FALSE, loops=TRUE, matrix.type="edgelist")
`
I can't figure out how to go from Igraph or ggraph to plotting that same network (with the weights on the nodes and edges) onto a shapefile or map.
