Draw an interactive donut map — donut

donut_leaflet() returns a leaflet htmlwidget with clickable donut segments, optional origin-destination links or curved trajectories, popups, labels, a legend, and layer controls.

Usage

donut_leaflet(
  data,
  id,
  category,
  value,
  map = NULL,
  lon = NULL,
  lat = NULL,
  input_crs = 4326,
  crs = 3857,
  radius_range = NULL,
  inner_radius = 0.55,
  n = 96,
  colours = NULL,
  flows = NULL,
  from = NULL,
  to = NULL,
  flow_value = NULL,
  flow_group = NULL,
  flow_min = NULL,
  flow_weight_range = c(1, 8),
  flow_curvature = 0.18,
  flow_n = 30,
  flow_arrow = TRUE,
  flow_arrow_size = NULL,
  flow_colour = "grey35",
  flow_colours = NULL,
  flow_legend = TRUE,
  flow_legend_position = "topright",
  flow_opacity = 0.55,
  provider_tiles = "CartoDB.Positron",
  popup = TRUE,
  label = TRUE,
  prefer_canvas = FALSE,
  map_fill = "#f3f4f6",
  map_colour = "#ffffff",
  map_weight = 1,
  map_opacity = 0.9,
  donut_colour = "#ffffff",
  donut_weight = 1,
  donut_opacity = 0.9,
  donut_smooth_factor = 0
)

Arguments

data: A data frame or sf object. Each row is one category for one donut location.
id: Unquoted column identifying each donut location.
category: Unquoted column identifying donut categories.
value: Unquoted numeric column giving non-negative category values.
map: Optional sf object used as a background layer.
lon, lat: Unquoted longitude and latitude columns. Required when data is not an sf object.
input_crs: Coordinate reference system for lon and lat, or for an sf object with missing CRS. Defaults to EPSG:4326.
crs: Target projected CRS used to build interactive donut and trajectory geometries. Defaults to EPSG:3857, Leaflet's default display projection, so donut circles and sector separators remain visually regular on screen.
radius_range: Numeric vector of length 2 giving minimum and maximum donut radii in map units. If NULL, a range is derived from the map extent.
inner_radius: Numeric value in (0, 1) giving the inner radius as a proportion of the outer radius.
n: Number of points used to approximate a complete outer circle.
colours: Optional category colours. Use a named vector for stable category-colour matching.
flows: Optional data frame of origin-destination flows.
from, to: Unquoted columns in flows identifying origin and destination ids. Required when flows is supplied.
flow_value: Optional unquoted numeric column in flows used to scale line widths. If omitted, each flow receives value 1.
flow_group: Optional unquoted column in flows used to colour flow lines and arrowheads by group.
flow_min: Optional minimum flow value to draw.
flow_weight_range: Numeric vector of length 2 controlling interactive flow line weights.
flow_curvature: Numeric curvature for trajectory lines. Use 0 for straight lines, positive values for one bend direction, and negative values for the opposite direction.
flow_n: Number of points used to approximate each curved trajectory.
flow_arrow: Should interactive flow trajectories include arrowheads?
flow_arrow_size: Arrowhead length in projected map units. If NULL, a size is derived from the donut radii.
flow_colour: Flow line colour used when flow_group is not supplied.
flow_colours: Optional colours for flow_group. Use a named vector for stable group-colour matching. If omitted and flow groups match donut categories, colours is reused.
flow_legend: Should a separate flow colour legend be shown when flow_group is supplied?
flow_legend_position: Position of the flow colour legend.
flow_opacity: Flow line opacity.
provider_tiles: Leaflet provider tiles. Use NULL to skip tile layers.
popup: Should popups be attached to donut segments and flow lines?
label: Should hover labels be attached to donut segments and flow lines?
prefer_canvas: Should Leaflet prefer Canvas over SVG for vector rendering? The default FALSE gives crisper small donut separators.
map_fill, map_colour: Background map fill and outline colours.
map_weight: Background map border weight.
map_opacity: Background map opacity.
donut_colour: Donut segment border colour.
donut_weight: Donut segment border weight.
donut_opacity: Donut segment fill opacity.
donut_smooth_factor: Leaflet path simplification factor for donut polygons. The default 0 preserves the donut vertices so arcs and sector separators are not simplified by Leaflet.

Value

A leaflet htmlwidget.

Examples

demo <- data.frame(
  place = rep(c("A", "B", "C"), each = 3),
  lon = rep(c(-71.35, -71.2, -71.05), each = 3),
  lat = rep(c(46.75, 46.82, 46.73), each = 3),
  category = rep(c("x", "y", "z"), times = 3),
  value = c(10, 20, 5, 5, 15, 10, 12, 4, 9)
)

donut_leaflet(demo, place, category, value, lon = lon, lat = lat)