Add Text

Source: R/map_layer_text.R

The Text Layer renders text labels on the map

add_text(
  map,
  data = get_map_data(map),
  text,
  lon = NULL,
  lat = NULL,
  polyline = NULL,
  fill_colour = NULL,
  fill_opacity = NULL,
  size = NULL,
  angle = NULL,
  anchor = NULL,
  alignment_baseline = NULL,
  billboard = TRUE,
  font_family = "Monaco, monospace",
  font_weight = "normal",
  tooltip = NULL,
  layer_id = NULL,
  id = NULL,
  auto_highlight = FALSE,
  highlight_colour = "#AAFFFFFF",
  palette = "viridis",
  na_colour = "#808080FF",
  legend = FALSE,
  legend_options = NULL,
  legend_format = NULL,
  update_view = TRUE,
  focus_layer = FALSE,
  digits = 6,
  transitions = NULL,
  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
text

column of data containing the text. The data must be a character.
lon

column containing longitude values
lat

column containing latitude values
polyline

optional column of data containing the polylines, if using encoded polylines
fill_colour

column of data or hex colour for the fill colour. If using a hex colour, use either a single value, or a column of hex colours on data
fill_opacity

Either a string specifying the column of data containing the opacity of each shape, or a single value in [0,255], or [0, 1), to be applied to all the shapes. Default 255. If a hex-string is used as the colour, this argument is ignored and you should include the alpha on the hex string
size

column of data containing the size of the text. Default 32
angle

column of data containging the angle of the text. Default 0
anchor

column of data containing the anchor of the text. One of 'start', 'middle' or 'end'
alignment_baseline

column of data containing the alignment. One of 'top', 'center' or 'bottom'
billboard

logical indicating if the text always faces the camera (TRUE) or if it always faces up (FALSE)
font_family

specifies a prioritised list of one or more font family names and/or generic family names. Follow the specifics for CSS font-family https://developer.mozilla.org/en-US/docs/Web/CSS/font-family
font_weight

specifies the font weight. Follow the specifics for CSS font-weight https://htmldog.com/references/css/properties/font-weight/
tooltip

variable of data containing text or HTML to render as a tooltip
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
id

an id value in data to identify layers when interacting in Shiny apps.
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.
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
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
transitions

list specifying the duration of transitions.
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_text supports POINT and MULTIPOINT sf objects

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 text

list( position = 0, fill_colour = 0, angle = 0, size = 0 )

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


# \donttest{

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

mapdeck(
  style = mapdeck_style('dark')
) %>%
  add_text(
    data = capitals
    , lon = 'lon'
    , lat = 'lat'
    , fill_colour = 'country'
    , text = 'capital'
    , layer_id = 'text'
  )
# }