Add a symbol layer to a map

Usage

add_symbol_layer(
  map,
  id,
  source,
  source_layer = NULL,
  icon_allow_overlap = NULL,
  icon_anchor = NULL,
  icon_color = NULL,
  icon_color_brightness_max = NULL,
  icon_color_brightness_min = NULL,
  icon_color_contrast = NULL,
  icon_color_saturation = NULL,
  icon_emissive_strength = NULL,
  icon_halo_blur = NULL,
  icon_halo_color = NULL,
  icon_halo_width = NULL,
  icon_ignore_placement = NULL,
  icon_image = NULL,
  icon_image_cross_fade = NULL,
  icon_keep_upright = NULL,
  icon_offset = NULL,
  icon_opacity = NULL,
  icon_optional = NULL,
  icon_padding = NULL,
  icon_pitch_alignment = NULL,
  icon_rotate = NULL,
  icon_rotation_alignment = NULL,
  icon_size = NULL,
  icon_text_fit = NULL,
  icon_text_fit_padding = NULL,
  icon_translate = NULL,
  icon_translate_anchor = NULL,
  symbol_avoid_edges = NULL,
  symbol_placement = NULL,
  symbol_sort_key = NULL,
  symbol_spacing = NULL,
  symbol_z_elevate = NULL,
  symbol_z_order = NULL,
  text_allow_overlap = NULL,
  text_anchor = NULL,
  text_color = "black",
  text_emissive_strength = NULL,
  text_field = NULL,
  text_font = NULL,
  text_halo_blur = NULL,
  text_halo_color = NULL,
  text_halo_width = NULL,
  text_ignore_placement = NULL,
  text_justify = NULL,
  text_keep_upright = NULL,
  text_letter_spacing = NULL,
  text_line_height = NULL,
  text_max_angle = NULL,
  text_max_width = NULL,
  text_offset = NULL,
  text_opacity = NULL,
  text_optional = NULL,
  text_padding = NULL,
  text_pitch_alignment = NULL,
  text_radial_offset = NULL,
  text_rotate = NULL,
  text_rotation_alignment = NULL,
  text_size = NULL,
  text_transform = NULL,
  text_translate = NULL,
  text_translate_anchor = NULL,
  text_variable_anchor = NULL,
  text_writing_mode = NULL,
  visibility = "visible",
  slot = NULL,
  min_zoom = NULL,
  max_zoom = NULL,
  popup = NULL,
  tooltip = NULL,
  hover_options = NULL,
  before_id = NULL,
  filter = NULL,
  cluster_options = NULL
)

Arguments

map: A map object created by the mapboxgl or maplibre functions.
id: A unique ID for the layer.
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).
icon_allow_overlap: If TRUE, the icon will be visible even if it collides with other previously drawn symbols.
icon_anchor: Part of the icon placed closest to the anchor.
icon_color: The color of the icon. This is not supported for many Mapbox icons; read more at https://docs.mapbox.com/help/troubleshooting/using-recolorable-images-in-mapbox-maps/.
icon_color_brightness_max: The maximum brightness of the icon color.
icon_color_brightness_min: The minimum brightness of the icon color.
icon_color_contrast: The contrast of the icon color.
icon_color_saturation: The saturation of the icon color.
icon_emissive_strength: The strength of the icon's emissive color.
icon_halo_blur: The blur applied to the icon's halo.
icon_halo_color: The color of the icon's halo.
icon_halo_width: The width of the icon's halo.
icon_ignore_placement: If TRUE, the icon will be visible even if it collides with other symbols.
icon_image: Name of image in sprite to use for drawing an image background. To use values in a column of your input dataset, use get_column('YOUR_ICON_COLUMN_NAME'). Images can also be loaded with the add_image() function which should precede the add_symbol_layer() function.
icon_image_cross_fade: The cross-fade parameter for the icon image.
icon_keep_upright: If TRUE, the icon will be kept upright.
icon_offset: Offset distance of icon.
icon_opacity: The opacity at which the icon will be drawn.
icon_optional: If TRUE, the icon will be optional.
icon_padding: Padding around the icon.
icon_pitch_alignment: Alignment of the icon with respect to the pitch of the map.
icon_rotate: Rotates the icon clockwise.
icon_rotation_alignment: Alignment of the icon with respect to the map.
icon_size: The size of the icon, specified relative to the original size of the image. For example, a value of 5 would make the icon 5 times larger than the original size, whereas a value of 0.5 would make the icon half the size of the original.
icon_text_fit: Scales the text to fit the icon.
icon_text_fit_padding: Padding for text fitting the icon.
icon_translate: The offset distance of the icon.
icon_translate_anchor: Controls the frame of reference for icon-translate.
symbol_avoid_edges: If TRUE, the symbol will be avoided when near the edges.
symbol_placement: Placement of the symbol on the map.
symbol_sort_key: Sorts features in ascending order based on this value.
symbol_spacing: Spacing between symbols.
symbol_z_elevate: Elevates the symbol z-axis.
symbol_z_order: Orders the symbol z-axis.
text_allow_overlap: If TRUE, the text will be visible even if it collides with other previously drawn symbols.
text_anchor: Part of the text placed closest to the anchor.
text_color: The color of the text.
text_emissive_strength: The strength of the text's emissive color.
text_field: Value to use for a text label.
text_font: Font stack to use for displaying text.
text_halo_blur: The blur applied to the text's halo.
text_halo_color: The color of the text's halo.
text_halo_width: The width of the text's halo.
text_ignore_placement: If TRUE, the text will be visible even if it collides with other symbols.
text_justify: The justification of the text.
text_keep_upright: If TRUE, the text will be kept upright.
text_letter_spacing: Spacing between text letters.
text_line_height: Height of the text lines.
text_max_angle: Maximum angle of the text.
text_max_width: Maximum width of the text.
text_offset: Offset distance of text.
text_opacity: The opacity at which the text will be drawn.
text_optional: If TRUE, the text will be optional.
text_padding: Padding around the text.
text_pitch_alignment: Alignment of the text with respect to the pitch of the map.
text_radial_offset: Radial offset of the text.
text_rotate: Rotates the text clockwise.
text_rotation_alignment: Alignment of the text with respect to the map.
text_size: The size of the text.
text_transform: Transform applied to the text.
text_translate: The offset distance of the text.
text_translate_anchor: Controls the frame of reference for text-translate.
text_variable_anchor: Variable anchor for the text.
text_writing_mode: Writing mode for the text.
visibility: Whether this layer is displayed.
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. Not all elements of SVG icons can be styled.
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.
cluster_options: A list of options for clustering symbols, created by the cluster_options() function.

Value

The modified map object with the new symbol layer added.

Examples

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

# Set seed for reproducibility
set.seed(1234)

# Define the bounding box for Washington DC (approximately)
bbox <- st_bbox(
    c(
        xmin = -77.119759,
        ymin = 38.791645,
        xmax = -76.909393,
        ymax = 38.995548
    ),
    crs = st_crs(4326)
)

# Generate 30 random points within the bounding box
random_points <- st_as_sf(
    data.frame(
        id = 1:30,
        lon = runif(30, bbox["xmin"], bbox["xmax"]),
        lat = runif(30, bbox["ymin"], bbox["ymax"])
    ),
    coords = c("lon", "lat"),
    crs = 4326
)

# Assign random icons
icons <- c("music", "bar", "theatre", "bicycle")
random_points <- random_points |>
    mutate(icon = sample(icons, n(), replace = TRUE))

# Map with icons
mapboxgl(style = mapbox_style("light")) |>
    fit_bounds(random_points, animate = FALSE) |>
    add_symbol_layer(
        id = "points-of-interest",
        source = random_points,
        icon_image = c("get", "icon"),
        icon_allow_overlap = TRUE,
        tooltip = "icon"
    )
} # }