R/wdi_leaflet.R

In walkerke/kwgeo: Miscellaneous functions for manipulating and visualizing geographic data

#' Function to create a Leaflet interactive map in RStudio from a World Bank indicator.
#' @export
#' @import WDI rgdal sp leaflet


wdi_leaflet <- function(indicator, indicator_alias = "Value", year = 2012, classes = 5, colors = "Blues") {

  url <- "http://www.naturalearthdata.com/http//www.naturalearthdata.com/download/50m/cultural/ne_50m_admin_0_countries.zip"

  tmp <- tempdir()

  file <- basename(url)

  download.file(url, file)

  unzip(file, exdir = tmp)

  countries <- readOGR(dsn = tmp,
                       layer = "ne_50m_admin_0_countries",
                       encoding = "UTF-8",
                       verbose = FALSE)


  dat <- WDI(country = "all",
             indicator = indicator,
             start = year,
             end = year)

  dat[[indicator]] <- round(dat[[indicator]], 1)



  countries2 <- geo_join(countries, dat,"iso_a2", "iso2c")

  pal <- colorQuantile(colors, NULL, n = classes)

  labs <- quantile_labels(countries2[[indicator]], classes)

  country_popup <- paste0("<strong>Country: </strong>",
                          countries2$name_long,
                          "<br><strong>",
                          indicator_alias,
                          ", ",
                          as.character(year),
                          ": </strong>",
                          countries2[[indicator]])

  stamen_tiles <- "http://{s}.tile.stamen.com/toner-lite/{z}/{x}/{y}.png"

  stamen_attribution <- 'Map tiles by <a href="http://stamen.com">Stamen Design</a>, under <a href="http://creativecommons.org/licenses/by/3.0">CC BY 3.0</a>. Data by <a href="http://openstreetmap.org">OpenStreetMap</a>, under <a href="http://www.openstreetmap.org/copyright">ODbL</a>.'

  leaflet(data = countries2) %>%
    addTiles(urlTemplate = stamen_tiles,
             attribution = stamen_attribution) %>%
    setView(0, 0, zoom = 2) %>%
    addPolygons(fillColor = ~pal(countries2[[indicator]]),
                fillOpacity = 0.8,
                color = "#BDBDC3",
                weight = 1,
                popup = country_popup) %>%
    addLegend(colors = c(RColorBrewer::brewer.pal(classes, colors), "#808080"),
              position = "bottomright",
              bins = classes,
              labels = labs,
              title = paste0(indicator_alias, ", ", as.character(year))
    )

}

## Example call

## wdi_leaflet(indicator = "SP.RUR.TOTL.ZS", indicator_alias = "Percent rural", colors = "PuBu")