add_trips {mapdeck}

Add Trips

Description

The Trips Layer takes an sf object with Z (elevation) and M (time) attributes and renders it as animated trips

Usage

add_trips(
  map,
  data = get_map_data(map),
  stroke_colour = NULL,
  stroke_width = NULL,
  width_units = c("meters", "pixels"),
  width_min_pixels = NULL,
  width_max_pixels = NULL,
  width_scale = 1,
  opacity = 0.3,
  palette = "viridis",
  trail_length = 180,
  start_time = get_m_range_start(data),
  end_time = get_m_range_end(data),
  animation_speed = 30,
  layer_id = NULL,
  legend = FALSE,
  legend_options = NULL,
  legend_format = NULL,
  update_view = TRUE,
  focus_layer = FALSE,
  digits = 6,
  ...
)

Arguments

map

a mapdeck map object

data

sf object with XYZM dimensions.

stroke_colour

variable of data or hex colour for the stroke.

stroke_width

width of the stroke in meters. Default 1.

width_units

The units of the line width, one of 'meters', 'common' or 'pixels'. When zooming in and out, meter sizes scale with the base map, and pixel sizes remain the same on screen.

width_min_pixels

The minimum path width in pixels. This can be used to prevent the path from getting too thin when zoomed out.

width_max_pixels

The maximum path width in pixels. his prop can be used to prevent the path from getting too thick when zoomed in.

width_scale

The path width multiplier that multiplied to all paths.

opacity

single value in [0,1]

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")

trail_length

how long it takes for the trail to completely fade out (in same units as timestamps )

start_time

the minimum timestamp

end_time

the maximum timestamp

animation_speed

speed of animation

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

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

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

digits

number of digits for rounding coordinates

...

clear_legend and clear_view arguments passed to 'clear_()' functions

Details

add_trips supports LINESTRING and MULTILINESTRING sf objects

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.

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

Examples

set_token( "MAPBOX_TOKEN")
sf <- city_trail

mapdeck(
  style = mapdeck_style("dark")
) %>%
 add_trips(
   data = sf
   , animation_speed = 500
   , trail_length = 500
   , stroke_colour = "#FFFFFF"
   , stroke_width = 25
)

## Multi-coloured trips
## requires a colour for each coordiante
## In this example I'm assining the elevation (z) value
## to a new column
df <- sfheaders::sf_to_df( city_trail )
df$colour <- df$z
sf <- sfheaders::sf_linestring(
  obj = df
  , x = "x"
  , y = "y"
  , z = "z"
  , m = "m"
  , keep = TRUE
  , list_column = "colour"
)

mapdeck(
  style = mapdeck_style("light")
) %>%
 add_trips(
   data = sf
   , animation_speed = 1000
   , trail_length = 1000
   , stroke_colour = "colour"
   , stroke_width = 50
   , legend = TRUE
)

## New York Taxi Trips
json <- jsonify::from_json(
  "https://raw.githubusercontent.com/visgl/deck.gl-data/master/examples/trips/trips.json"
)

lens <- vapply( json$segments, nrow, 1L )
mat <- do.call( rbind, json$segments )
df <- setNames( as.data.frame( mat ), c("x","y","m") )
idx <- rep( seq_along( lens ), times = lens )
df$vendor <- rep( json$vendor, times = lens )

df$z <- 0 ## z column is required in SF object
df$idx <- idx

## Using the timestamp as a colour
df$timestamp <- df$m

sf_line <- sfheaders::sf_linestring(
  obj = df
  , x = "x"
  , y = "y"
  , z = "z"
  , m = "m"
  , linestring_id = "idx"
  , keep = TRUE
  , list_column = "timestamp"
)

mapdeck(
  style = mapdeck_style("dark")
) %>%
  add_trips(
    data = sf_line
    , stroke_colour = "timestamp"
    , animation_speed = 1000
    , trail_length = 1000
    , palette = colourvalues::get_palette("viridis")[100:256, ]
  )