add_circle_layer: Add a circle layer to a Mapbox GL map

In mapgl: Interactive Maps with 'Mapbox GL JS' and 'MapLibre GL JS'

Add a circle layer to a Mapbox GL map

Description

Add a circle layer to a Mapbox GL map

Usage

add_circle_layer(
  map,
  id,
  source,
  source_layer = NULL,
  circle_blur = NULL,
  circle_color = NULL,
  circle_opacity = NULL,
  circle_radius = NULL,
  circle_sort_key = NULL,
  circle_stroke_color = NULL,
  circle_stroke_opacity = NULL,
  circle_stroke_width = NULL,
  circle_translate = NULL,
  circle_translate_anchor = "map",
  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 function.
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).
circle_blur	Amount to blur the circle.
circle_color	The color of the circle.
circle_opacity	The opacity at which the circle will be drawn.
circle_radius	Circle radius.
circle_sort_key	Sorts features in ascending order based on this value.
circle_stroke_color	The color of the circle's stroke.
circle_stroke_opacity	The opacity of the circle's stroke.
circle_stroke_width	The width of the circle's stroke.
circle_translate	The geometry's offset. Values are c(x, y) where negatives indicate left and up.
circle_translate_anchor	Controls the frame of reference for circle-translate.
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.
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 circles, created by the cluster_options() function.

Value

The modified map object with the new circle layer added.

Examples

## Not run: 
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 categories
categories <- c("music", "bar", "theatre", "bicycle")
random_points <- random_points %>%
    mutate(category = sample(categories, n(), replace = TRUE))

# Map with circle layer
mapboxgl(style = mapbox_style("light")) %>%
    fit_bounds(random_points, animate = FALSE) %>%
    add_circle_layer(
        id = "poi-layer",
        source = random_points,
        circle_color = match_expr(
            "category",
            values = c(
                "music", "bar", "theatre",
                "bicycle"
            ),
            stops = c(
                "#1f78b4", "#33a02c",
                "#e31a1c", "#ff7f00"
            )
        ),
        circle_radius = 8,
        circle_stroke_color = "#ffffff",
        circle_stroke_width = 2,
        circle_opacity = 0.8,
        tooltip = "category",
        hover_options = list(
            circle_radius = 12,
            circle_color = "#ffff99"
        )
    ) %>%
    add_categorical_legend(
        legend_title = "Points of Interest",
        values = c("Music", "Bar", "Theatre", "Bicycle"),
        colors = c("#1f78b4", "#33a02c", "#e31a1c", "#ff7f00"),
        circular_patches = TRUE
    )

## End(Not run)

mapgl documentation built on Nov. 1, 2024, 5:08 p.m.