valuemap {valuemap}

Making choropleth map with sf polygons

Description

This function make a leaflet object. You can easily visualize your sf polygons based on "value" column. You have options : background map (= map) color legend boundary values (= legend.cut) color palette for color legend (= palette) showing "value" number on center of polygons (= show.text) color for "value" number text on center of polygons (= text.color)

Usage

valuemap(
  data,
  map = providers$OpenStreetMap,
  legend.cut = NULL,
  palette = "Blues",
  show.text = TRUE,
  text.color = "black",
  text.format = function(x) x
)

Arguments

data

A sf object with polygons who has "name" & "value" columns ("value" column must be numeric type)

map

A map name of leaflet::providers

legend.cut

A numeric vector which means color legend boundary values

palette

A color name of RColorBrewer palettes

show.text

A boolean who determines showing "value" number on center of polygons

text.color

A color name for "value" number text on center of polygons

text.format

A format function for "value" number text on center of polygons

Value

A leaflet object.

Examples

# Only run this example in interactive R sessions
if (interactive()) valuemap(seoul)

# Emphasize great of equal to 20 polygons
if (interactive()) valuemap(seoul, legend.cut=c(20))

# Visualize without center number on polygons
if (interactive()) valuemap(seoul, legend.cut=c(15,17,20), show.text=FALSE)

# Change color palette & center number on polygons text color, format & change background map
if (interactive())
  valuemap(
    seoul, map=providers$Stamen.Toner, palette='YlOrRd',
    text.color='blue', text.format=function(x) paste(x,'EA')
  )