Manually creating points for Leaflet map

Question

I'm creating a few points to plot on a Leaflet-R map. However, when trying to plot the points with addCircles I am getting the error:

Warning: Error in derivePoints: Point data not found; please provide addCircles with data and/or lng/lat arguments

The info about the spatial data frame reads:

Simple feature collection with 3 features and 4 fields
geometry type:  POINT
dimension:      XY
bbox:           xmin: -79.48837 ymin: 43.66537 xmax: -79.29187 ymax: 43.71345
epsg (SRID):    4326
proj4string:    +proj=longlat +datum=WGS84 +no_defs

I have another spatial data frame that works and all the info is the same except that +datum=WGS84 is replaced with +ellps=WGS84. Could that be it? If so, how do I make this change?

Sample Code

library(shiny)
library(leaflet)

ui <- fluidPage(
  leafletOutput("mymap")
)

server <- function(input, output, session) {

  # Create tree geometries
  tree_1g <- st_point(c(-79.2918671415814, 43.6760766531298))
  tree_2g <- st_point(c(-79.4883669334101, 43.6653747165064))
  tree_3g <- st_point(c(-79.2964680812039, 43.7134458013647))

  # Create sfc object with multiple sfg objects
  points_sfc <- st_sfc(tree_1g, tree_2g, tree_3g, crs = 4326)

  # Create tree attributes
  data <- data.frame (
    id = c(1, 2, 3),
    address = c(10, 20, 30),
    street = c("first", "second", "third"),
    tname = c("oak", "elm", "birch")
)

  tree_data <- st_sf(data, geometry = points_sfc)

  output$mymap <- renderLeaflet({
    leaflet() %>%
      addProviderTiles(providers$Stamen.Watercolor) %>%

      # Centre the map in the middle of Toronto
      setView(lng = -79.384293, 
              lat = 43.685, #43.653908, 
              zoom = 11) %>% 

      addCircles(tree_data)
  })
}

shinyApp(ui, server)

Answer 1

Solution

You need to specify data = tree_data, because within the addCircles() call the data argument is the last one.

leaflet() %>%
    addProviderTiles(providers$Stamen.Watercolor) %>%
    setView(lng = -79.384293, 
                    lat = 43.685,
                    zoom = 11) %>% 

    addCircles(data = tree_data)

---

Explanation

The first argument in the addCircles() call is the map, which is passed in through the %>% operator. The second argument is lng, so what you're doing in your call is equivalent to

addCircles(lng = tree_data)

---

Alternative

Another way to send the data into the addCircles() function is through the leaflet() call

leaflet(tree_data) %>%
    addProviderTiles(providers$Stamen.Watercolor) %>%
    setView(lng = -79.384293, 
                    lat = 43.685,
                    zoom = 11) %>% 
    addCircles()