qPRAentry (version 0.1.0)

plot_countries: Plot values on a map at country level

Description

Plots country values on a map using data provided and allows customisation of various aesthetics, such as colors, legend title, and title.

Usage

plot_countries(
  data,
  iso_col,
  values_col,
  colors = NULL,
  na_value = "grey",
  title = NULL,
  legend_title = NULL
)

Value

A ggplot object with the plotted countries.

Arguments

data

A data frame containing the values to be plotted on the map.

iso_col

A string specifying the column name in data with the ISO 3166-1 (alpha-2) country codes. See ISO 3166 Maintenance Agency for details on country codes.

values_col

A string specifying the column name in data with the values to be plotted.

colors

Optional vector of colors used in the gradient scale.

na_value

Color for missing values (default is "grey").

title

A title for the plot (default is NULL).

legend_title

A title for the legend. Default NULL, name in the values_col.

Details

Extracts an sf object from the giscoR package. It uses the ggplot2 package for the representation. Also, it supports the addition of other ggplot2 options (see examples).

Examples

# Simulated data trade in Northern America
data("datatrade_NorthAm")
# Mean of internal production for each country
library(dplyr)
data_plot <- datatrade_NorthAm$internal_production %>% 
  group_by(reporter) %>% 
  summarise(mean_value = mean(value))

head(data_plot)

#Plot
pl <- plot_countries(data = data_plot,
                     iso_col = "reporter",
                     values_col = "mean_value")
pl

# Changing colors and adding other ggplot2 options
library(ggplot2)
pl <- plot_countries(data = data_plot,
                     iso_col = "reporter",
                     values_col = "mean_value",
                     colors = c("white", "lightblue", "darkblue"),
                     title = "Plot internal production",
                     legend_title = "units")
pl + 
  xlim(-170, -20) + ylim(10, 90) +
  theme_bw()