Colour specific countries on a worldmap and adding mappoint cities - r

Question

I want to design a worldmap to show from which country and which city the participants to my survey come from. I used the highcharter package.
First part is : colour the countries --> it worked well ! A scale is created from 0 to 1.
Second part is : adding the cities --> the points are created but the countries colored in blue disappeared ! The scale has changed and is now induced from cities.
I try to change the order of my code but nothing is working.
library(dplyr)
library(maps)
library(magrittr)
# I use the dataset called iso3166 from the {maps} package and rename it date
dat <- iso3166
head(dat)
# I rename the variable a3 by iso-a3
dat <- rename(dat, "iso-a3" = a3)
head(dat)
# I create a vector with the countries I want to colour
part1X_countries <- c("CHE", "FRA", "USA", "GBR", "CAN", "BRA")
dat$part1X <- ifelse(dat$`iso-a3` %in% part1X_countries, 1, 0)
head(dat)
# I add the name of cities with geographical coordinates
cities <- data.frame(
name = c("St Gallen", "Fort Lauderdale", "Paris", "Nottingham", "Winnipeg", "Chicago", "Leeds", "Montréal", "New Rochelle", "São Paulo", "Saint-Genis-Pouilly", "Canterbury"),
lat = c(47.42391, 26.122438, 48.866667, 52.950001, 49.8955, 41.881832, 53.801277, 45.5016889, 40.9232, -23.5489, 46.24356, 51.279999),
lon = c(9.37477, -80.137314, 2.333333, -1.150000, -97.1383, -87.623177, -1.548567, -73.567256, -73.7793, -46.6388, 6.02119, 1.080000))
# I create my worldmap with countries and cities
worldmap <- hcmap(
map = "custom/world-highres3", # high resolution world map
data = dat, # name of dataset
value = "part1X",
joinBy = "iso-a3",
showInLegend = FALSE, # hide legend
download_map_data = TRUE
) %>%
hc_add_series(
data = cities,
type = "mappoint",
name = "Cities"
) %>%
hc_title(text = "Representation of participants by country")```

Answer 1

You need to define a colorkey and add a color axis for the hcmap. The below code keeps the colors from the countries and has the name of the countries added on top as black map points.
worldmap <- hcmap(
map = "custom/world-highres3", # high resolution world map
data = dat, # name of dataset
value = "part1X",
joinBy = "iso-a3",
colorKey = "value",
showInLegend = F, # hide legend
download_map_data = TRUE) %>%
hc_colorAxis(min = min(dat$part1X),
max = max(dat$part1X)) %>%
hc_add_series(
data = cities,
type = "mappoint",
name = "Cities",
dataLabels = list(enabled = TRUE, format = '{point.name}'),
latField = "lat",
longField = "lon",
# color = "color"
valueField = "part1X"
) %>%
hc_title(text = "Representation of participants by country")
worldmap