R: Add UI controls to switch layers on and off

addLayersControl {leaflet} | R Documentation

## Add UI controls to switch layers on and off

### Description

Uses Leaflet's built-in layers control feature to allow users to choose one of several base layers, and to choose any number of overlay layers to view.

### Usage

    addLayersControl(map, baseGroups = character(0),
      overlayGroups = character(0), position = c("topright", "bottomright",
      "bottomleft", "topleft"), options = layersControlOptions())

    layersControlOptions(collapsed = TRUE, autoZIndex = TRUE, ...)

    removeLayersControl(map)

### Arguments

`map` | the map to add the layers control to
`baseGroups` | character vector where each element is the name of a group. The user will be able to choose one base group (only) at a time. This is most commonly used for mostly-opaque tile layers.
`overlayGroups` | character vector where each element is the name of a group. The user can turn each overlay group on or off independently.
`position` | position of control: 'topleft', 'topright', 'bottomleft', or 'bottomright'
`options` | a list of additional options, intended to be provided by a call to `layersControlOptions`
`collapsed` | if `TRUE` (the default), the layers control will be rendered as an icon that expands when hovered over. Set to `FALSE` to have the layers control always appear in its expanded state.
`autoZIndex` | if `TRUE`, the control will automatically maintain the z-order of its various groups as overlays are switched on and off.
`...` | other options for `layersControlOptions()`

### Examples

    leaflet() %>%
      addTiles(group = "OpenStreetMap") %>%
      addProviderTiles("Stamen.Toner", group = "Toner by Stamen") %>%
      addMarkers(runif(20, -75, -74), runif(20, 41, 42), group = "Markers") %>%
      addLayersControl(
        baseGroups = c("OpenStreetMap", "Toner by Stamen"),
        overlayGroups = c("Markers")
      )

[Package leaflet version 1.1.0 Index]