spatialrisk (version 0.7.3)

choropleth: Create choropleth map

Description

Creates a choropleth map from an `sf` object, typically produced by points_to_polygon(). Polygons are shaded according to values in a specified column, with clustering based on the Fisher–Jenks algorithm. This method minimizes within-class variance and maximizes between-class variance, making it a common choice for choropleth maps.

Usage

choropleth(
  sf_object,
  value = "output",
  id_name = "areaname",
  mode = "plot",
  n = 7,
  legend_title = "Clustering",
  palette = "viridis"
)

Value

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

Arguments

sf_object

An object of class sf.

value

A string giving the name of the column used to shade the polygons.

id_name

A string giving the name of the column containing polygon IDs (used for tooltips in interactive mode).

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".

Author

Martin Haringa

Details

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

Examples

test <- points_to_polygon(nl_provincie, insurance, sum(amount, na.rm = TRUE))
choropleth(test)
choropleth(test, id_name = "areaname", mode = "view")