rggplot2plotrworldmap

R - Print specific country names in a map using rworldmap


I am creating a heatmap using the map of Europe in rworldmap package in R (since I don't know how to do this with ggmap or ggplot2).

I need to plot the country names of the countries that are present in my dataframe only, not all european countries. How can I do this? My code:

library(RColorBrewer)
#getting colours
colourPalette <- brewer.pal(5,'RdPu')


library(rworldmap)

europe <- data.frame(
  "country" = c("Greece", 
                "France", 
                "Spain",
                "Italy",
                "UK",
                "Finland","Norway","Sweden",
                "Germany",
                "Romania"), 
  "x" = c(2.5, 3, 2.2, 1.8,2.32, 1.99, 2.01, 2.34, 1.88, 2.45))

matched <- joinCountryData2Map(europe, joinCode="NAME", nameJoinColumn="country")





mapParams <- mapCountryData(matched, 
                            nameColumnToPlot="x", 
                            mapTitle="my Titley", 
                            addLegend=FALSE,
                            mapRegion="Europe"
                            ,colourPalette=colourPalette,
                            oceanCol="#404040", missingCountryCol="#A0A0A0")



#adding legend
do.call(addMapLegend
        ,c(mapParams
           ,legendLabels="all"
           ,legendWidth=0.5
           ,legendIntervals="data"
           ,legendMar = 2))

labelCountries()

Using labelCountries() prints all country names and it's not readable.

Thanks


Solution

  • With a little bit help of this previously answer:

    # get the coordinates for each country
    country_coord<-data.frame(coordinates(matched),stringsAsFactors=F)
    
    # label the countries
    country = c("Greece", 
                  "France", 
                  "Spain",
                  "Italy",
                  "UK",
                  "Finland","Norway","Sweden",
                  "Germany",
                  "Romania")
    
    #filter your wanted countrys
    country_coord = country_coord[country,]
    
    #insert your labels in plot
    text(x=country_coord$X1,y=country_coord$X2,labels=row.names(country_coord))
    

    you can add the country labels with text but you must extract the coordinates before from your matched coordinates. Output:

    plot

    You might play a bit with col = "color" in text, since some country can barely been read. Or maybe change the color scale in your map