Is is possible to color path by elevation?

I'm using mapdeck::add_path() to show aircraft flight paths. I would like to color the paths by elevation; is this possible? Here is a short example:

library(mapdeck)
library(sf)
# From https://github.com/kent37/mapdeck_play/blob/master/tracks_2019_03_11.gpkg?raw=true
one_day = st_read('tracks_2019_03_11.gpkg')

key = 'your_api_key'
mapdeck(location=c(-71.128184, 42.3769824), zoom=14, key=key) %>% 
  add_path(one_day)

Thanks!

Update 2024-01-03

The way to do this is to supply a colour-per-vertex. Which in sf temrs means you need to add a list-column, where each list element is the same length as the number of coordinate pairs in the LINESTRING

df_roads <- sfheaders::sf_to_df(mapdeck::roads, fill = TRUE)

## Add a random value for each coordinate
## These will become our colours at each vertex
df_roads$random <- sample(0:100, size = nrow(df_roads), replace = TRUE)

## rebuild the sf and include the `random` column as a `list`, so the value 
## persists per vertex
sf_roads <- sfheaders::sf_linestring(
    obj = df_roads
    , x = "x"
    , y = "y"
    , linestring_id = "linestring_id"
    , list_columns = "random"
    , keep = TRUE
)

mapdeck() %>%
    add_path(
        data = sf_roads
        , stroke_colour = "random"
        , stroke_width = 10
    )

Original answer

It's currently not possible to have a multi-coloured path, but it is on my todo list.

To achieve what you're after you'll have to use a line layer, which takes an 'origin' and 'destination' and draws a straight line (i.e., the constituent parts of a path)

To get the Origin-Destination columns we need to decompose the sf object into a data.frame, add the '_to' columns, then make it an sf object again.

(I also have a todo to allow data.frames to use Z and M, but for now we have to do this final conversion to sf again)

library(data.table)
library(sfheaders)

df <- sfheaders::sf_to_df( one_day, fill = TRUE )

setDT( df )[
  , `:=`(
    x_to = shift(x, type = "lead")
    , y_to = shift(y, type = "lead")
    , z_to = shift(z, type = "lead")
    , m_to = shift(m, type = "lead")
    )
  , by = flight
]

df <- df[ !is.na( x_to ) ]

df$origin <- sfheaders::sfc_point(
  obj = df
  , x = "x"
  , y = "y"
  , z = "z"
  , m = "m"
)

df$destination <- sfheaders::sfc_point(
  obj = df
  , x = "x_to"
  , y = "y_to"
  , z = "z_to"
  , m = "m_to"
)

sf <- sf::st_as_sf( df )

mapdeck(
  style = mapdeck_style("dark")
) %>%
  add_line(
    data = sf
    , origin = "origin"
    , destination = "destination"
    , stroke_colour = "z"
  )