Plotting on a geographical map the provenience of our patients - r

Question

I am trying to put on a Italian geographical map a dot reporting the provenience ('provincia') of our patients. Ideally, the dot size should be proportional to the number of patients coming from that 'provincia'. An example of the list I would like to plot is the following.
MI 8319
CO 537
MB 436
VA 338
BG 310
PV 254
CR 244
NO 210
RM 189
CS 179
In the first column there is the 'provincia' code: MI (Milano), CO (Como), MB (Monza-Brianza), etc. In the second column there is the number of patients from that 'provincia'. So the output should be an Italian political map where the biggest dot is around the city of Milano (MI), the second biggest dot is near the city of Como (CO), the third one is around the city of Monza-Brianza (MB),etc.
Is there any package that could do the plot I am looking for? I found a tool that could do the job here, but apparently they expect that I load the geographical coordinates in order to do the plot.
https://www.littlemissdata.com/blog/maps
Thanks in advance.

Answer 1

Here is one way to handle your task. You have the abbreviations for Italian province. You want to use them to merge your data with polygon data. If you download Italy's polygons from GADM, you can obtain data that contain the abbreviations. Specifically, the column, HASC_2 is the one. You need to merge your data with the polygon data. Then, you want to create another data set which contains centroid. You can draw a map with the two data sets.
library(tidyverse)
library(sf)
library(ggthemes)
# Get the sf file from https://gadm.org/download_country_v3.html
# and import it in R.
mysf <- readRDS("gadm36_ITA_2_sf.rds")
# This is your data, which is called mydata.
mydata <- structure(list(abbs = c("MI", "CO", "MB", "VA", "BG", "PV", "CR",
"NO", "RM", "CS"), value = c(8319L, 537L, 436L, 338L, 310L, 254L,
244L, 210L, 189L, 179L)), class = "data.frame", row.names = c(NA,
-10L))
abbs value
1 MI 8319
2 CO 537
3 MB 436
4 VA 338
5 BG 310
6 PV 254
7 CR 244
8 NO 210
9 RM 189
10 CS 179
# Abbreviations are in HASC_2 in mysf. Manipulate strings so that
# I can join mydata with mysf with the abbreviations. I also get
# longitude and latitude with st_centroid(). This data set is for
# geom_point().
mysf2 <- mutate(mysf, HASC_2 = sub(x = HASC_2, pattern = "^IT.", replacement = "")) %>%
left_join(mydata, by = c("HASC_2" = "abbs")) %>%
mutate(lon = map_dbl(geometry, ~st_centroid(.x)[[1]]),
lat = map_dbl(geometry, ~st_centroid(.x)[[2]]))
# Draw a map
ggplot() +
geom_sf(data = mysf) +
geom_point(data = mysf2, aes(x = lon, y = lat, size = value)) +
theme_map()

Answer 2

UPDATE ON INSET MAP
This is an update following different suggestion on using inset maps, which I think it would be the best solution for yout question and comments:
library(sf)
library(cartography)
EU = st_read("~/R/mapslib/EUROSTAT/NUTS_RG_03M_2016_3035_LEVL_3.geojson")
IT = subset(EU, CNTR_CODE == "IT")
mydata <-
structure(list(
abbs = c("MI", "CO", "MB", "VA", "BG", "PV", "CR",
"NO", "RM", "CS"),
value = c(8319L, 537L, 436L, 338L, 310L, 254L,
244L, 210L, 189L, 179L),
nuts = c("ITC4C","ITC42","ITC4D","ITC41",
"ITC46", "ITC48","ITC4A","ITC15",
"ITI43","ITF61")
),
class = "data.frame",
row.names = c(NA, -10L))
patients = merge(IT, mydata, by.x = "id", by.y = "nuts")
#Get breaks for map
br=getBreaks(patients$value)
#Delimit zone
#Based on NUTS1, Nortwest Italy
par(mar=c(0,0,0,0))
ghostLayer(IT[grep("ITC",IT$NUTS_ID),], bg="lightblue")
plot(st_geometry(EU), col="grey90", add=TRUE)
plot(st_geometry(IT), col = "#FEFEE9", border = "#646464", add=TRUE)
choroLayer(
patients,
var = "value",
breaks = br,
col = carto.pal(pal1 = "red.pal", n1 = length(br)-1),
legend.pos = "topleft",
legend.title.txt = "Total patients",
add = TRUE,
legend.frame = TRUE
)
labelLayer(patients,txt="abbs", halo=TRUE, overlap = FALSE)
#Inset
par(
fig = c(0, 0.4, 0.01, 0.4),
new = TRUE
)
inset=patients[patients$abbs %in% c("RM","CS"),]
ghostLayer(inset, bg="lightblue")
plot(st_geometry(EU), col="grey90", add=TRUE)
plot(st_geometry(IT), col = "#FEFEE9", border = "#646464", add=TRUE)
choroLayer(
patients,
var = "value",
breaks = br,
col = carto.pal(pal1 = "red.pal", n1 = length(br)-1),
legend.pos = "n",
add = TRUE
)
labelLayer(patients,txt="abbs", halo=TRUE, overlap = FALSE)
box(which = "figure", lwd = 1)
#RESTORE PLOT
par(fig=c(0,1,0,1))
OLD ANSWER
Following my comment on plotting labels, maybe with circles is not the best option for your map, given the concentration. I suggest you to use another kind of map for that, as chorolayer, I leveraged on https://stackoverflow.com/users/3304471/jazzurro for the dataframe.
library(sf)
library(cartography)
EU = st_read("~/R/mapslib/EUROSTAT/NUTS_RG_03M_2016_3035_LEVL_3.geojson")
IT = subset(EU, CNTR_CODE == "IT")
mydata <-
structure(list(
abbs = c("MI", "CO", "MB", "VA", "BG", "PV", "CR",
"NO", "RM", "CS"),
value = c(8319L, 537L, 436L, 338L, 310L, 254L,
244L, 210L, 189L, 179L),
nuts = c("ITC4C","ITC42","ITC4D","ITC41",
"ITC46", "ITC48","ITC4A","ITC15",
"ITI43","ITF61")
),
class = "data.frame",
row.names = c(NA, -10L))
patients = merge(IT, mydata, by.x = "id", by.y = "nuts")
#Options1 - With circles
par(mar = c(0, 0, 0, 0))
plot(st_geometry(IT), col = "#FEFEE9", border = "#646464")
propSymbolsLayer(
x = patients,
var = "value",
col = carto.pal(pal1 = "red.pal", n1 = 6),
legend.title.txt = "Total patients",
add = TRUE
)
#Option 2 - Chorolayer with labels
par(mar = c(0, 0, 0, 0))
plot(st_geometry(IT), col = "#FEFEE9", border = "#646464")
choroLayer(
patients,
var = "value",
col = carto.pal(pal1 = "red.pal", n1 = 6),
legend.title.txt = "Total patients",
add = TRUE
)
#Create labels
patients$label = paste(patients$abbs, patients$value, sep = " - ")
labelLayer(
patients,
txt = "label",
overlap = FALSE,
halo = TRUE,
show.lines = TRUE,
)
Data from
https://ec.europa.eu/eurostat/cache/GISCO/distribution/v2/nuts/nuts-2016-files.html