Add polyline

Add a polyline to a google map

add_polylines(map, data = get_map_data(map), polyline = NULL,
  lat = NULL, lon = NULL, id = NULL, geodesic = NULL,
  stroke_colour = NULL, stroke_weight = NULL, stroke_opacity = NULL,
  info_window = NULL, mouse_over = NULL, mouse_over_group = NULL,
  draggable = NULL, editable = NULL, update_map_view = TRUE,
  layer_id = NULL, z_index = NULL, digits = 4, palette = NULL,
  legend = F, legend_options = NULL, load_interval = 0,
  focus_layer = FALSE)

Arguments

map

a googleway map object created from google_map()
data

data frame containing at least a polyline column, or a lat and a lon column. If Null, the data passed into google_map() will be used.
polyline

string specifying the column of data containing the encoded polyline
lat

string specifying the column of data containing the 'latitude' coordinates. If left NULL, a best-guess will be made
lon

string specifying the column of data containing the 'longitude' coordinates. If left NULL, a best-guess will be made
id

string specifying the column containing an identifier for a shape
geodesic

logical
stroke_colour

either a string specifying the column of data containing the stroke colour of each shape, or a valid hexadecimal numeric HTML style to be applied to all the shapes
stroke_weight

either a string specifying the column of data containing the stroke weight of each shape, or a number indicating the width of pixels in the line to be applied to all the shapes
stroke_opacity

either a string specifying the column of data containing the stroke opacity of each shape, or a value between 0 and 1 that will be applied to all the shapes
info_window

string specifying the column of data to display in an info window when a shape is clicked.
mouse_over

string specifying the column of data to display when the mouse rolls over the shape
mouse_over_group

string specifying the column of data specifying which groups of shapes to highlight on mouseover
draggable

string specifying the column of data defining if the polygon is 'draggable'. The column of data should be logical (either TRUE or FALSE)
editable

string specifying the column of data defining if the polygon is 'editable' (either TRUE or FALSE)
update_map_view

logical specifying if the map should re-centre according to the shapes
layer_id

single value specifying an id for the layer. Use this value to distinguish between shape layers for when using any update_ function, and for separating legends.
z_index

single value specifying where the circles appear in the layering of the map objects. Layers with a higher z_index appear on top of those with a lower z_index. See details.
digits

integer. Use this parameter to specify how many digits (decimal places) should be used for the latitude / longitude coordinates.
palette

a function, or list of functions, that generates hex colours given a single number as an input. See details.
legend

either a logical indiciating if the legend(s) should be displayed, or a named list indicating which colour attributes should be included in the legend.
legend_options

A list of options for controlling the legend.
load_interval

time in miliseconds to wait between plotting each shape
focus_layer

logical indicating if the map should re-centre according to this layer

Details

z_index values define the order in which objects appear on the map. Those with a higher value appear on top of those with a lower value. The default order of objects is (1 being underneath all other objects)

  • 1. Polygon

  • 2. Rectangle

  • 3. Polyline

  • 4. Circle

Markers are always the top layer

Note

The lines can be generated by either using an encoded polyline, or by a set of lat/lon coordinates. You sould specify either the column containing an encoded polyline, OR the lat / lon colulmns.

Using update_map_view = TRUE for multiple polylines may be slow, so it may be more appropriate to set the view of the map using the location argument of google_map()

palette

The palette is used to specify the colours that will map to variables. You can specify a single function to map to all variables, or a named list that specifies a separate function to map to each variable. The elements must be named either fill_colour or stroke_colour, and their values are the colour generating functions. The default is viridisLite::viridis

The legend_options can be used to control the appearance of the legend. This should be a named list, where the names are one of

if legend_options are NULL, the default values will apply

If you are displaying two legends, one for stroke_colour and one for fill_colour, you can specify different options for the different colour attributes. See examples for add_circles.

Examples

# NOT RUN {
## using lat/lon coordinates

set_key("your_api_key")

google_map(data = tram_route) %>%
  add_polylines(lat = "shape_pt_lat", lon = "shape_pt_lon")


google_map() %>%
  add_polylines(data = melbourne, polyline = "polyline", stroke_weight = 1,
      stroke_colour = "SA4_NAME")

## using encoded polyline and various colour / fill options
url <- 'https://raw.githubusercontent.com/plotly/datasets/master/2011_february_aa_flight_paths.csv'
flights <- read.csv(url)
flights$id <- seq_len(nrow(flights))


## encode the routes as polylines
lst <- lapply(unique(flights$id), function(x){
  lat = c(flights[flights["id"] == x, c("start_lat")], flights[flights["id"] == x, c("end_lat")])
  lon = c(flights[flights["id"] == x, c("start_lon")], flights[flights["id"] == x, c("end_lon")])
  data.frame(id = x, polyline = encode_pl(lat = lat, lon = lon))
})

flights <- merge(flights, do.call(rbind, lst), by = "id")

style <- map_styles()$night

google_map(key = map_key, style = style) %>%
  add_polylines(data = flights, polyline = "polyline", mouse_over_group = "airport1",
               stroke_weight = 1, stroke_opacity = 0.3, stroke_colour = "#ccffff")


# }