pal <- colorFactor(
  palette = 'Dark2',
  domain = df$area
)


leaflet(df) %>%
  #addTiles() %>%  # Add default OpenStreetMap map tiles
  addProviderTiles(providers$CartoDB.Positron) %>%
  setView(mean(df$Longitude), mean(df$Latitude), zoom = 11)%>% 
  addCircleMarkers(lng=df$Longitude, lat=df$Latitude,radius = 0.0004*(df$total_pics), color = ~pal(df$area), label = as.character(paste(df$Location_ID,
    "\nTotal images: ", df$total_pics, sep="")))