Add a tooltip that puts each value in context — add_context

Adds a tooltip to a layer that shows, on hover (or tap on touch screens), a feature's value together with where it stands among all features: its rank, the share of features with a lower value, the difference with the average, and a small distribution strip with the feature marked.

Usage

add_context_tooltip(
  map,
  layer_id,
  column,
  name_column = NULL,
  label = column,
  weight = NULL,
  unit = "features",
  locale = "en-US",
  digits = 1,
  prefix = "",
  suffix = "",
  diff_suffix = NULL,
  color = NULL,
  highlight = TRUE,
  highlight_color = "#1f2328",
  labels = context_labels()
)

Arguments

map: A map created with mapgl::maplibre() or mapgl::mapboxgl().
layer_id: ID of the layer to summarise: a polygon layer (such as mapgl::add_fill_layer()) or a point layer (such as mapgl::add_circle_layer() or mapgl::add_symbol_layer()). Its source must be an sf object or inline GeoJSON added in R; vector tile sources are not supported.
column: Name of the numeric column to show.
name_column: Optional column with feature names, shown as the tooltip's title.
label: Name of the variable shown in the panel. Defaults to column.
weight: Optional numeric column used to weight the average, for example population.
unit: Name for the features, shown as "14 of 528 unit".
locale: Locale for number formatting, such as "en-US" or "es-AR".
digits: Number of decimals for values. Values of a million or more are abbreviated, such as 12.4M.
prefix, suffix: Text added before and after each value, such as "$" or "%".
diff_suffix: Text added after the difference between the view and the overall average. NULL (the default) uses suffix, except when suffix contains "%": a difference between percentages is in percentage points, so the points label is used instead.
color: Color for the feature's marker on the distribution strip. NULL (the default) uses the layer's own color scale when it is an interpolate() or step_expr() on column, and blue otherwise.
highlight: If TRUE, outlines the feature under the pointer.
highlight_color: Color of that outline.
labels: Panel texts, as returned by context_labels().

Value

The modified map object.

Details

Use it instead of the layer's own tooltip argument: with both, two tooltips are shown.

Examples

if (FALSE) { # \dontrun{
library(mapgl)

maplibre(center = c(-64, -38.5), zoom = 3.4) |>
  add_fill_layer(
    id = "deptos",
    source = ar_departments,
    fill_color = interpolate(
      column = "growth",
      values = c(-10, 0, 10),
      stops = c("#b2182b", "#f7f7f7", "#2166ac")
    )
  ) |>
  add_context_tooltip(
    layer_id = "deptos",
    column = "growth",
    name_column = "department",
    label = "Population growth",
    unit = "departments",
    suffix = "%"
  )
} # }