leaflet

22 / 6 / 2018

library(leaflet)
my_map <- leaflet() %>% addTiles()

adding markers

my_map <- my_map %>% 
  addMarkers(lat = 39.2980803, lng = -76.5898801, popup = "Jeff Leek's office" )

# may_map <-addMarkers(my_map, lat = 39.2980803, lng = -76.5898801, popup = "Jeff Leek's office" )

why is piping important

my_map <- 
  leaflet() %>%
  addTiles() %>% 
  addMarkers(lat = 39.2980803, lng = -76.5898801, popup = "Jeff Leek's office" )

my_map

## adding many markers

set.seed(2016-04-25)
df <- data.frame(lat = runif(20, min = 39.2, max = 39.3),
                 lng = runif(20, min = -76.6, max = -76.5))
df %>%
  leaflet() %>%
  addTiles()%>%
  addMarkers()

## Making Custom Markers

hopkinsIcon <- makeIcon(
  # you need icons !! not images
  iconUrl = "https://thenounproject.com/term/rose/",
  iconWidth = 31*215/230, iconHeight = 31,
  iconAnchorX = 31*215/230/2, iconAnchorY = 16
)

hopkinsLatLong <- data.frame(
  lat = c (39.273166, 39.3288851, 36.2906617, 39.2970681, 39.282406),
  lng = c (-76.5929798, -76.6206598, -76.5469683, -76.6150537, -76.6016766)
)

hopkinsLatLong %>%
  leaflet() %>%
  addTiles()%>%
  addMarkers(icon = hopkinsIcon)

clustering maps

df <- data.frame(
  lat = runif(500,min = 39.25, max = 39.35),
  lng = runif(500,min = -76.65, max = -76.55))
df %>%
  leaflet() %>%
  addTiles() %>%
  addMarkers(clusterOptions = markerClusterOptions())

mapping circle

df %>%
  leaflet() %>%
  addTiles() %>%
  addCircleMarkers()

draw shapes

md_cities <- data.frame(name = c ("A", "B", "C", "D", "E", "F", "G", "H"),
                        pop = c (619493, 66169, 62334, 61045, 55232,
                                 39890, 38880, 30587),
                        lat = c (39.2920592, 39.4143921, 39.0840, 38.9748 ,39.273166, 39.3288851, 36.2906617, 39.2970681),
                       lng = c (-76.6077852,-77.4204875,-77.1528,-77.1528,-76.5929798, -76.6206598, -76.5469683, -76.6150537)
)

md_cities %>%
  leaflet() %>%
  addTiles() %>%
  addCircles(weight = 1, radius = sqrt(md_cities$pop) * 30)

## Assuming "lng" and "lat" are longitude and latitude, respectively

rectangles

leaflet() %>%
  addTiles() %>%
  addRectangles(lat1 = 37.3858, lng1 = -122.0595,
                lat2 = 37.3890, lng2 = -122.0625)

different colors & legends

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 ("blue", "red", "green"))

## Assuming "lng" and "lat" are longitude and latitude, respectively