November 7, 2017

df <- data.frame(lat = runif(20, min = 39.25, max = 39.35), lng = runif(20, min = -76.65, max = -76.55), col = sample(c("red", "blue", "green"), 20, replace = TRUE), stringsAsFactors = FALSE)

df %>%
  leaflet() %>%
  addTiles() %>%
  addCircleMarkers(color = df$col) %>%
  addLegend(labels = LETTERS[1:3], colors = c("red", "blue", "green"))