choropleth: Create a choropleth map of polygon-level values

In spatialrisk: Spatial Concentration and Radius-Based Risk Calculations

Create a choropleth map of polygon-level values

Description

Creates a choropleth map from an 'sf' object containing polygon-level reporting values, for example one produced by summarise_points_by_polygon(). Polygons are shaded according to values in a specified column, with clustering based on the Fisher–Jenks algorithm.

Usage

choropleth(
  data,
  value = "output",
  id = NULL,
  mode = c("plot", "view"),
  n = 7,
  legend_title = "Value",
  palette = "viridis",
  id_name = NULL,
  ...,
  basemaps = c("Esri.WorldGrayCanvas", "OpenStreetMap", "Esri.WorldImagery")
)

Arguments

data	An object of class sf.
value	A string giving the name of the column used to shade the polygons.
id	Optional string giving the name of the column containing polygon IDs used for tooltips.
mode	A string indicating whether to create a static map ("plot", default) or an interactive map ("view").
n	Integer; number of clusters. Default is 7.
legend_title	A string giving the legend title.
palette	A palette name or vector of colors. See tmaptools::palette_explorer() for available palettes. Prefix the name with "-" to reverse the order. Default is "viridis".
id_name	Deprecated. Use id instead.
...	Additional arguments passed to tmap::tm_polygons().
basemaps	Character vector of basemap providers for mode = "view". The first provider is shown initially; the others are available in the layer control. Defaults to "Esri.WorldGrayCanvas", "OpenStreetMap", and "Esri.WorldImagery". Ignored in static mode. Passed to tmap::tm_basemap().

Details

The function uses the Fisher–Jenks algorithm (style = "fisher") to classify values into n groups.

Value

A tmap object (static or interactive, depending on mode).

Author(s)

Martin Haringa

Examples

test <- summarise_points_by_polygon(nl_provincie, insurance, "amount")
choropleth(test, value = "amount_sum")
## Not run: 
choropleth(test, value = "amount_sum", id = "areaname", mode = "view")
choropleth(test, value = "amount_sum", mode = "view",
           basemaps = "Esri.WorldImagery")

## End(Not run)

spatialrisk documentation built on Oct. 16, 2026, 5:09 p.m.