add_layer function

Add a layer to a map from a source

In many cases, you will use add_layer() internal to other layer-specific functions in mapgl. Advanced users will want to use add_layer() for more fine-grained control over the appearance of their layers.

add_layer(
  map,
  id,
  type = "fill",
  source,
  source_layer = NULL,
  paint = list(),
  layout = list(),
  slot = NULL,
  min_zoom = NULL,
  max_zoom = NULL,
  popup = NULL,
  tooltip = NULL,
  hover_options = NULL,
  before_id = NULL,
  filter = NULL
)

Arguments

• map: A map object created by the mapboxgl() or maplibre() functions.
• id: A unique ID for the layer.
• type: The type of the layer (e.g., "fill", "line", "circle").
• source: The ID of the source, alternatively an sf object (which will be converted to a GeoJSON source) or a named list that specifies type and url for a remote source.
• source_layer: The source layer (for vector sources).
• paint: A list of paint properties for the layer.
• layout: A list of layout properties for the layer.
• slot: An optional slot for layer order.
• min_zoom: The minimum zoom level for the layer.
• max_zoom: The maximum zoom level for the layer.
• popup: A column name containing information to display in a popup on click. Columns containing HTML will be parsed.
• tooltip: A column name containing information to display in a tooltip on hover. Columns containing HTML will be parsed.
• hover_options: A named list of options for highlighting features in the layer on hover.
• before_id: The name of the layer that this layer appears "before", allowing you to insert layers below other layers in your basemap (e.g. labels).
• filter: An optional filter expression to subset features in the layer.

Returns

The modified map object with the new layer added.

Examples

## Not run:

# Load necessary libraries
library(mapgl)
library(tigris)

# Load geojson data for North Carolina tracts
nc_tracts <- tracts(state = "NC", cb = TRUE)

# Create a Mapbox GL map
map <- mapboxgl(
    style = mapbox_style("light"),
    center = c(-79.0193, 35.7596),
    zoom = 7
)

# Add a source and fill layer for North Carolina tracts
map %>%
    add_source(
        id = "nc-tracts",
        data = nc_tracts
    ) %>%
    add_layer(
        id = "nc-layer",
        type = "fill",
        source = "nc-tracts",
        paint = list(
            "fill-color" = "#888888",
            "fill-opacity" = 0.4
        )
    )
## End(Not run)