Add arc

The Arc Layer renders raised arcs joining pairs of source and target coordinates

add_arc(
  map,
  data = get_map_data(map),
  layer_id = NULL,
  origin,
  destination,
  id = NULL,
  stroke_from = NULL,
  stroke_from_opacity = NULL,
  stroke_to = NULL,
  stroke_to_opacity = NULL,
  stroke_width = NULL,
  tilt = NULL,
  height = NULL,
  tooltip = NULL,
  auto_highlight = FALSE,
  highlight_colour = "#AAFFFFFF",
  legend = F,
  legend_options = NULL,
  legend_format = NULL,
  palette = "viridis",
  na_colour = "#808080FF",
  update_view = TRUE,
  focus_layer = FALSE,
  transitions = NULL,
  digits = 6,
  brush_radius = NULL
)

Arguments

map	a mapdeck map object
data	data to be used in the layer. All coordinates are expected to be EPSG:4326 (WGS 84) coordinate system
layer_id	single value specifying an id for the layer. Use this value to distinguish between shape layers of the same type. Layers with the same id are likely to conflict and not plot correctly
origin	vector of longitude and latitude columns, and optionally an elevation column, or an sfc column
destination	vector of longitude and latitude columns, and optionally an elevatino column, or an sfc column
id	an id value in data to identify layers when interacting in Shiny apps.
stroke_from	column of data or hex colour to use as the staring stroke colour. IIf using a hex colour, use either a single value, or a column of hex colours on data
stroke_from_opacity	Either a string specifying the column of data containing the stroke opacity of each shape, or a value between 1 and 255 to be applied to all the shapes. If a hex-string is used as the colour, this argument is ignored and you should include the alpha on the hex string
stroke_to	column of data or hex colour to use as the ending stroke colour. If using a hex colour, use either a single value, or a column of hex colours on data
stroke_to_opacity	Either a string specifying the column of data containing the stroke opacity of each shape, or a value between 1 and 255 to be applied to all the shapes. If a hex-string is used as the colour, this argument is ignored and you should include the alpha on the hex string
stroke_width	width of the stroke in pixels
tilt	value to tilt the arcs to the side, in degrees [-90, 90]
height	value to multiply the height.
tooltip	variable of data containing text or HTML to render as a tooltip
auto_highlight	logical indicating if the shape under the mouse should auto-highlight
highlight_colour	hex string colour to use for highlighting. Must contain the alpha component.
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.
legend_format	A list containing functions to apply to legend values. See section legend
palette	string or matrix. String will be one of colourvalues::colour_palettes(). A matrix must have at least 5 rows, and 3 or 4 columns of values between [0, 255], where the 4th column represents the alpha. You can use a named list to specify a different palette for different colour options (where available), e.g. list(fill_colour = "viridis", stroke_colour = "inferno")
na_colour	hex string colour to use for NA values
update_view	logical indicating if the map should update the bounds to include this layer
focus_layer	logical indicating if the map should update the bounds to only include this layer
transitions	list specifying the duration of transitions.
digits	number of digits for rounding coordinates
brush_radius	radius of the brush in metres. Default NULL. If supplied, the arcs will only show if the origin or destination are within the radius of the mouse. If NULL, all arcs are displayed

Details

add_arc supports POINT sf objects

MULTIPOINT objects will be treated as single points. That is, if an sf objet has one row with a MULTIPOINT object consisting of two points, this will be expanded to two rows of single POINTs. Therefore, if the origin is a MULTIPOINT of two points, and the destination is a single POINT, the code will error as there will be an uneven number of rows

data

If data is a simple feature object, you need to supply the origin and destination columns, they aren't automatically detected.

id

The id is returned to your R session from an interactive shiny environment by observing layer clicks. This is useful for returning the data.frame row relating to the cliked shape.

From within a shiny server you would typically use observeEvent({input$map_arc_click}), where 'map' is the map_id supplied to mapdeckOutput(), and 'arc' is the layer you are clicking on

legend

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

• css - a string of valid css for controlling the appearance of the legend

• title - a string to use for the title of the legend

• digits - number to round the legend values to

If the layer allows different fill and stroke colours, you can use different options for each. See examples in add_arc.

The legend_format can be used to control the format of the values in the legend. This should be a named list, where the names are one of

• fill_colour

• stroke_colour

depending on which type of colouring the layer supports.

The list elements must be functions to apply to the values in the legend.

transitions

The transitions argument lets you specify the time it will take for the shapes to transition from one state to the next. Only works in an interactive environment (Shiny) and on WebGL-2 supported browsers and hardware.

The time is in milliseconds

Available transitions for arc

list( origin = 0, destination = 0, stroke_from = 0, stroke_to = 0, stroke_width = 0 )

Examples

# \donttest{

## You need a valid access token from Mapbox
key <- 'abc'
set_token( key )

url <- 'https://raw.githubusercontent.com/plotly/datasets/master/2011_february_aa_flight_paths.csv'
flights <- read.csv(url)
flights$id <- seq_len(nrow(flights))
flights$stroke <- sample(1:3, size = nrow(flights), replace = T)
flights$info <- paste0("<b>",flights$airport1, " - ", flights$airport2, "</b>")

mapdeck( style = mapdeck_style("dark"), pitch = 45 ) %>%
  add_arc(
  data = flights
  , layer_id = "arc_layer"
  , origin = c("start_lon", "start_lat")
  , destination = c("end_lon", "end_lat")
  , stroke_from = "airport1"
  , stroke_to = "airport2"
  , stroke_width = "stroke"
  , tooltip = "info"
  , auto_highlight = TRUE
  , legend = T
  , legend_options = list(
    stroke_from = list( title = "Origin airport" ),
    css = "max-height: 100px;")
 )

mapdeck( style = mapdeck_style("dark")) %>%
  add_arc(
  data = flights
  , layer_id = "arc_layer"
  , origin = c("start_lon", "start_lat")
  , destination = c("end_lon", "end_lat")
  , stroke_from = "airport1"
  , stroke_to = "airport2"
  , stroke_width = "stroke"
  )

## Arcs can have an elevated start & destination
flights$start_elev <- sample(100000:1000000, size = nrow(flights), replace = TRUE )

mapdeck( style = mapdeck_style("dark")) %>%
  add_arc(
  data = flights
  , layer_id = "arc_layer"
  , origin = c("start_lon", "start_lat", "start_elev")
  , destination = c("end_lon", "end_lat", "start_elev")
  , stroke_from = "airport1"
  , stroke_to = "airport2"
  , stroke_width = "stroke"
  )

## Using a 2-sfc-column sf object
library(sfheaders)

sf_flights <- sfheaders::sf_point(
  flights
  , x = "start_lon"
  , y = "start_lat"
  , z = "start_elev"
  , keep = TRUE
  )
destination <- sfheaders::sfc_point(
  flights
  , x = "end_lon"
  , y = "end_lat"
  , z = "start_elev"
  )

sf_flights$destination <- destination

mapdeck(
) %>%
 add_arc(
   data = sf_flights
   , origin = 'geometry'
   , destination = 'destination'
   , layer_id = 'arcs'
   , stroke_from = "airport1"
   , stroke_to = "airport2"
)

## using a brush

mapdeck(
  , style = mapdeck_style("light")
) %>%
 add_arc(
   data = sf_flights
   , origin = 'geometry'
   , destination = 'destination'
   , layer_id = 'arcs'
   , stroke_from = "airport1"
   , stroke_to = "airport2"
   , stroke_width = 4
   , brush_radius = 500000
)



# }