inst/examples/labels.R

In rstudio/leaflet: Create Interactive Web Maps with the JavaScript 'Leaflet' Library

library(leaflet)

# Marker + Label on hover
leaflet() %>% addTiles() %>%
  addMarkers(
    lng = -118.456554, lat = 34.078039,
    label = "This is a label")
#' <br/><br/>

# Marker + Static Labels
leaflet() %>% addTiles() %>%
  addMarkers(
    lng = -118.456554, lat = 34.078039,
    label = "This is a static label",
    labelOptions = labelOptions(noHide = TRUE))
#' <br/><br/>

# Circle Marker + Label in all 4 directions.
# Note the offset values for top and bottom directions.
leaflet() %>% addTiles() %>%
  setView(
    lng = -118.456554, lat = 34.078039, zoom  = 16
  ) %>%
  addCircleMarkers(
    lng = -118.45990, lat = 34.078079, radius = 5,
    label = "On the Right",
    labelOptions = labelOptions(noHide = TRUE, direction = "right")
  ) %>%
  addCircleMarkers(
    lng = -118.45280, lat = 34.078079, radius = 5,
    label = "On the left",
    labelOptions = labelOptions(noHide = TRUE, direction = "left")
  ) %>%
  addCircleMarkers(
    lng = -118.456554, lat = 34.079979, radius = 5,
    label = "On the Top",
    labelOptions = labelOptions(noHide = TRUE, direction = "top",
                                offset = c(0, -15))
  ) %>%
  addCircleMarkers(
    lng = -118.456554, lat = 34.076279, radius = 5,
    label = "On the Bottom",
    labelOptions = labelOptions(noHide = TRUE, direction = "bottom",
                                offset = c(0, 15)))
#' <br/><br/>


# Change Text Size and text Only and also a custom CSS
leaflet() %>% addTiles() %>% setView(-118.456554, 34.09, 13) %>%
  addMarkers(
    lng = -118.456554, lat = 34.07,
    label = "Default Label",
    labelOptions = labelOptions(noHide = TRUE)) %>%
  addMarkers(
    lng = -118.456554, lat = 34.085,
    label = "Label w/o surrounding box",
    labelOptions = labelOptions(noHide = TRUE, textOnly = TRUE)) %>%
  addMarkers(
    lng = -118.456554, lat = 34.095,
    label = "label w/ textsize 15px",
    labelOptions = labelOptions(noHide = TRUE, textsize = "15px")) %>%
  addMarkers(
    lng = -118.456554, lat = 34.11,
    label = "Label w/ custom CSS style",
    labelOptions = labelOptions(noHide = TRUE, textOnly = FALSE,
                                style = list(
                                  "color" = "red",
                                  "font-family" = "serif",
                                  "font-style" = "italic",
                                  "box-shadow" = "3px 3px rgba(0,0,0,0.25)",
                                  "font-size" = "12px",
                                  "border-color" = "rgba(0,0,0,0.5)"
                                  )))
#' <br/><br/>

# Polygon + HTML Label
leaflet() %>% addTiles() %>%
  addRectangles(
    lng1 = -118.456554, lat1 = 34.078039,
    lng2 = -118.436383, lat2 = 34.062717,
    fillColor = "transparent",
    label = htmltools::HTML("<em>I'm a HTML Label</em>")
  )
#' <br/><br/>

# Examples with more than one Labels

cities <- read.csv(textConnection("
City,Lat,Long,Pop
Boston,42.3601,-71.0589,645966
Hartford,41.7627,-72.6743,125017
New York City,40.7127,-74.0059,8406000
Philadelphia,39.9500,-75.1667,1553000
Pittsburgh,40.4397,-79.9764,305841
Providence,41.8236,-71.4222,177994
"))
#' <br/><br/>

# Polygons with Label as formula
leaflet(cities) %>% addTiles() %>%
  addCircles(lng = ~Long, lat = ~Lat, weight = 1,
             radius = ~sqrt(Pop) * 30, label = ~as.character(City))
#' <br/><br/>

# Polygons with Label as formula and custom label options
leaflet(cities) %>% addTiles() %>%
  addCircles(lng = ~Long, lat = ~Lat, weight = 1,
             radius = ~sqrt(Pop) * 30, label = ~City,
               labelOptions = lapply(1:nrow(cities), function(x) {
                 labelOptions(opacity = 0.8)
               }))
#' <br/><br/>

# Markers with Label as formula and custom Label options
leaflet(cities) %>% addTiles() %>%
  addMarkers(lng = ~Long, lat = ~Lat,
             label = ~City,
             labelOptions = lapply(1:nrow(cities), function(x) {
               labelOptions(opacity = 0.9)
             }))
#' <br/><br/>


# Circle Markers with static Label as formula and custom Label options
leaflet(cities) %>% addTiles() %>%
  addCircleMarkers(lng = ~Long, lat = ~Lat,
             label = ~City,
             labelOptions = lapply(1:nrow(cities), function(x) {
               labelOptions(opacity = 1, noHide = TRUE,
                            direction = "auto", offset = c(20, -15))
             }))
#' <br/><br/>

# Markers with Label as HTMLized List and custom Label options
library(htmltools)
leaflet(cities) %>% addTiles() %>%
  addMarkers(lng = ~Long, lat = ~Lat,
             label = mapply(
               function(x, y) {
                 HTML(sprintf("<em>%s:</em> %s", htmlEscape(x), htmlEscape(y)))
               },
               cities$City, cities$Pop, SIMPLIFY = FALSE),
             labelOptions = lapply(1:nrow(cities), function(x) {
               labelOptions(direction = "auto")
             }))
#' <br/><br/>