how to plot networks over a map with the least overlap - r

Question

I have some authors with their city or country of affiliation. I would like to know if it is possible to plot the coauthors' networks (figure 1), on the map, having the coordinates of the countries. Please consider multiple authors from the same country. [EDIT: Several networks could be generated as in the example and should not show avoidable overlaps]. This is intended for dozens of authors. A zooming option is desirable. Bounty promise +100 for future better answer.
refs5 <- read.table(text="
row bibtype year volume number pages title journal author
Bennett_1995 article 1995 76 <NA> 113--176 angiosperms. \"Annals of Botany\" \"Bennett Md, Leitch Ij\"
Bennett_1997 article 1997 80 2 169--196 estimates. \"Annals of Botany\" \"Bennett MD, Leitch IJ\"
Bennett_1998 article 1998 82 SUPPL.A 121--134 weeds. \"Annals of Botany\" \"Bennett MD, Leitch IJ, Hanson L\"
Bennett_2000 article 2000 82 SUPPL.A 121--134 weeds. \"Annals of Botany\" \"Bennett MD, Someone IJ\"
Leitch_2001 article 2001 83 SUPPL.A 121--134 weeds. \"Annals of Botany\" \"Leitch IJ, Someone IJ\"
New_2002 article 2002 84 SUPPL.A 121--134 weeds. \"Annals of Botany\" \"New IJ, Else IJ\"" , header=TRUE,stringsAsFactors=FALSE)
rownames(refs5) <- refs5[,1]
refs5<-refs5[,2:9]
citations <- as.BibEntry(refs5)
authorsl <- lapply(citations, function(x) as.character(toupper(x$author)))
unique.authorsl<-unique(unlist(authorsl))
coauth.table <- matrix(nrow=length(unique.authorsl),
ncol = length(unique.authorsl),
dimnames = list(unique.authorsl, unique.authorsl), 0)
for(i in 1:length(citations)){
paper.auth <- unlist(authorsl[[i]])
coauth.table[paper.auth,paper.auth] <- coauth.table[paper.auth,paper.auth] + 1
}
coauth.table <- coauth.table[rowSums(coauth.table)>0, colSums(coauth.table)>0]
diag(coauth.table) <- 0
coauthors<-coauth.table
bip = network(coauthors,
matrix.type = "adjacency",
ignore.eval = FALSE,
names.eval = "weights")
authorcountry <- read.table(text="
author country
1 \"LEITCH IJ\" Argentina
2 \"HANSON L\" USA
3 \"BENNETT MD\" Brazil
4 \"SOMEONE IJ\" Brazil
5 \"NEW IJ\" Brazil
6 \"ELSE IJ\" Brazil",header=TRUE,fill=TRUE,stringsAsFactors=FALSE)
matched<- authorcountry$country[match(unique.authorsl, authorcountry$author)]
bip %v% "Country" = matched
colorsmanual<-c("red","darkgray","gainsboro")
names(colorsmanual) <- unique(matched)
gdata<- ggnet2(bip, color = "Country", palette = colorsmanual, legend.position = "right",label = TRUE,
alpha = 0.9, label.size = 3, edge.size="weights",
size="degree", size.legend="Degree Centrality") + theme(legend.box = "horizontal")
gdata
In other words, adding the names of authors, lines and bubbles to the map. Note, several authors maybe from the same city, or country and should not overlap.
Figure 1 Network
EDIT: The current JanLauGe answer overlaps two non-related networks. authors "ELSE" and "NEW" need to be apart from others as in figure 1.

Answer 1

Are you looking for a solution using exactly the packages you used, or would you be happy to use suite of other packages? Below is my approach, in which I extract the graph properties from the network object and plot them on a map using the ggplot2 and map package.
First I recreate the example data you gave.
library(tidyverse)
library(sna)
library(maps)
library(ggrepel)
set.seed(1)
coauthors <- matrix(
c(0,3,1,1,3,0,1,0,1,1,0,0,1,0,0,0),
nrow = 4, ncol = 4,
dimnames = list(c('BENNETT MD', 'LEITCH IJ', 'HANSON L', 'SOMEONE ELSE'),
c('BENNETT MD', 'LEITCH IJ', 'HANSON L', 'SOMEONE ELSE')))
coords <- data_frame(
country = c('Argentina', 'Brazil', 'USA'),
coord_lon = c(-63.61667, -51.92528, -95.71289),
coord_lat = c(-38.41610, -14.23500, 37.09024))
authorcountry <- data_frame(
author = c('LEITCH IJ', 'HANSON L', 'BENNETT MD', 'SOMEONE ELSE'),
country = c('Argentina', 'USA', 'Brazil', 'Brazil'))
Now I generate the graph object using the snp function network
# Generate network
bip <- network(coauthors,
matrix.type = "adjacency",
ignore.eval = FALSE,
names.eval = "weights")
# Graph with ggnet2 for centrality
gdata <- ggnet2(bip, color = "Country", legend.position = "right",label = TRUE,
alpha = 0.9, label.size = 3, edge.size="weights",
size="degree", size.legend="Degree Centrality") + theme(legend.box = "horizontal")
From the network object we can extract the values of each edge, and from the ggnet2 object we can get degree of centrality for nodes as below:
# Combine data
authors <-
# Get author numbers
data_frame(
id = seq(1, nrow(coauthors)),
author = sapply(bip$val, function(x) x$vertex.names)) %>%
left_join(
authorcountry,
by = 'author') %>%
left_join(
coords,
by = 'country') %>%
# Jittering points to avoid overlap between two authors
mutate(
coord_lon = jitter(coord_lon, factor = 1),
coord_lat = jitter(coord_lat, factor = 1))
# Get edges from network
networkdata <- sapply(bip$mel, function(x)
c('id_inl' = x$inl, 'id_outl' = x$outl, 'weight' = x$atl$weights)) %>%
t %>% as_data_frame
dt <- networkdata %>%
left_join(authors, by = c('id_inl' = 'id')) %>%
left_join(authors, by = c('id_outl' = 'id'), suffix = c('.from', '.to')) %>%
left_join(gdata$data %>% select(label, size), by = c('author.from' = 'label')) %>%
mutate(edge_id = seq(1, nrow(.)),
from_author = author.from,
from_coord_lon = coord_lon.from,
from_coord_lat = coord_lat.from,
from_country = country.from,
from_size = size,
to_author = author.to,
to_coord_lon = coord_lon.to,
to_coord_lat = coord_lat.to,
to_country = country.to) %>%
select(edge_id, starts_with('from'), starts_with('to'), weight)
Should look like this now:
dt
# A tibble: 8 × 11
edge_id from_author from_coord_lon from_coord_lat from_country from_size to_author to_coord_lon
<int> <chr> <dbl> <dbl> <chr> <dbl> <chr> <dbl>
1 1 BENNETT MD -51.12756 -16.992729 Brazil 6 LEITCH IJ -65.02949
2 2 BENNETT MD -51.12756 -16.992729 Brazil 6 HANSON L -96.37907
3 3 BENNETT MD -51.12756 -16.992729 Brazil 6 SOMEONE ELSE -52.54160
4 4 LEITCH IJ -65.02949 -35.214117 Argentina 4 BENNETT MD -51.12756
5 5 LEITCH IJ -65.02949 -35.214117 Argentina 4 HANSON L -96.37907
6 6 HANSON L -96.37907 36.252312 USA 4 BENNETT MD -51.12756
7 7 HANSON L -96.37907 36.252312 USA 4 LEITCH IJ -65.02949
8 8 SOMEONE ELSE -52.54160 -9.551913 Brazil 2 BENNETT MD -51.12756
# ... with 3 more variables: to_coord_lat <dbl>, to_country <chr>, weight <dbl>
Now moving on to plotting this data on a map:
world_map <- map_data('world')
myMap <- ggplot() +
# Plot map
geom_map(data = world_map, map = world_map, aes(map_id = region),
color = 'gray85',
fill = 'gray93') +
xlim(c(-120, -20)) + ylim(c(-50, 50)) +
# Plot edges
geom_segment(data = dt,
alpha = 0.5,
color = "dodgerblue1",
aes(x = from_coord_lon, y = from_coord_lat,
xend = to_coord_lon, yend = to_coord_lat,
size = weight)) +
scale_size(range = c(1,3)) +
# Plot nodes
geom_point(data = dt,
aes(x = from_coord_lon,
y = from_coord_lat,
size = from_size,
colour = from_country)) +
# Plot names
geom_text_repel(data = dt %>%
select(from_author,
from_coord_lon,
from_coord_lat) %>%
unique,
colour = 'dodgerblue1',
aes(x = from_coord_lon, y = from_coord_lat, label = from_author)) +
coord_equal() +
theme_bw()
Obviously you can change the colour and design in the usual way with ggplot2 grammar. Notice that you could also use geom_curve and the arrow aesthetic to get a plot similar to the one in the uber post linked in the comments above.

Answer 2

As an effort to avoid the overlapping of the 2 networks, I came to this modification of the x and y coordenates of the ggplot, which by default does not overlap the networks, see figure 1 in the question.
# get centroid positions for countries
# add coordenates to authorcountry table
# download and unzip
# https://worldmap.harvard.edu/data/geonode:country_centroids_az8
setwd("~/country_centroids_az8")
library(rgdal)
cent <- readOGR('.', "country_centroids_az8", stringsAsFactors = F)
countrycentdf<-cent#data[,c("name","Longitude","Latitude")]
countrycentdf$name[which(countrycentdf$name=="United States")]<-"USA"
colnames(countrycentdf)[names(countrycentdf)=="name"]<-"country"
authorcountry$Longitude<-countrycentdf$Longitude[match(authorcountry$country,countrycentdf$country)]
authorcountry$Latitude <-countrycentdf$Latitude [match(authorcountry$country,countrycentdf$country)]
# original coordenates of plot and its transformation
ggnetbuild<-ggplot_build(gdata)
allcoord<-ggnetbuild$data[[3]][,c("x","y","label")]
allcoord$Latitude<-authorcountry$Latitude [match(allcoord$label,authorcountry$author)]
allcoord$Longitude<-authorcountry$Longitude [match(allcoord$label,authorcountry$author)]
allcoord$country<-authorcountry$country [match(allcoord$label,authorcountry$author)]
# increase with factor the distance among dots
factor<-7
allcoord$coord_lat<-allcoord$y*factor+allcoord$Latitude
allcoord$coord_lon<-allcoord$x*factor+allcoord$Longitude
allcoord$author<-allcoord$label
# plot as in answer of JanLauGe, without jitter
library(tidyverse)
library(ggrepel)
authors <-
# Get author numbers
data_frame(
id = seq(1, nrow(coauthors)),
author = sapply(bip$val, function(x) x$vertex.names)) %>%
left_join(
allcoord,
by = 'author')
# Continue as in answer of JanLauGe
networkdata <- ##
dt <- ##
world_map <- map_data('world')
myMap <- ##
myMap