Add a reactive layer to map. — addReactiveFeatures • leafem

This function adds a layer to a map that is dependent on another layer. The reactive layer will be shown/hidden when holding the Ctrl-button on your keyboard and performing the action defined by on. on can be either "click" (default) or "mouseover".

Note: srcLayer needs to be added to the map using addGeoJSON because we need to be able to link the two layers by a common attribute defined by argument by. Linking will be done via group name of srcLayer.

Usage

addReactiveFeatures(
  map,
  x,
  srcLayer,
  by,
  on,
  group,
  layerId = NULL,
  options = NULL,
  style = NULL,
  updateStyle = NULL,
  popup = NULL,
  ...
)

Arguments

map: a mapview or leaflet object.
x: the (sf) features to be added to the map.
srcLayer: the group name of the source layer that x should be bound to.
by: shared attribute between x and srcLayer by which the two layers should be bound together.
on: the action to invoke the action. Can be one of "click" (default) and "mouseover". The action will be triggered by holding Ctrl-key and performing on.
group: the group name for the object to be added to map.
layerId: the layerId.
options: options to be passed to the layer. See e.g. pathOptions for details.
style: named list of styling instructions for the geometries in x.
updateStyle: named list of how to update the styling of the srcLayer.
popup: a character vector of the HTML content for the popups of layer x. See addControl for details.
...: currently not used.

Examples

library(leaflet)
library(leafem)
library(sf)
library(geojsonsf)

# create some random data
che = st_as_sf(gadmCHE)
pts = st_as_sf(st_sample(che, 200))
pts = st_join(pts, che[, "ID_1"])

che = sf_geojson(che)

leaflet() %>%
  addTiles() %>%
  addGeoJSON(che, group = "che") %>%
  addReactiveFeatures(
    pts
    , srcLayer = "che"
    , by = "ID_1"
    , on = "click"
    , group = "pts"
    , style = list(color = "black", fillOpacity = 0.3)
    , updateStyle = list(
      opacity = 0.3
      , fillOpacity = 0.3
      , color = "forestgreen"
      , fillColor = "forestgreen"
    )
  ) %>%
  addMouseCoordinates() %>%
  setView(lng = 8.31, lat = 46.75, zoom = 8)