blaeu
blaeu is a web mapping framework for R built on top of MapLibre GL.
Installation
You can install the development version of blaeu from
GitHub with devtools or pak:
devtools::install_github("program--/blaeu")
# install.packages("pak")
pak::pkg_install("program--/blaeu")
Example
Creating a map with a basemap:
blaeu::map(style = blaeu::carto("voyager"))
blaeu currently has functions for adding:
| Function | Description |
|---|---|
blaeu::openstreetmap() |
OpenStreetMap raster basemap tiles, |
blaeu::stamen() |
Stamen Watercolor, Terrain, and Toner raster basemap tiles, |
blaeu::carto() |
Carto Dark Matter, Voyager, and Positron vector basemap tiles. |
Adding points with sf objects:
example_data <- quakes
example_data$long <- ifelse(
example_data$long > 180,
example_data$long - 360,
example_data$long
)
example_data <- sf::st_as_sf(
example_data,
coords = c(2, 1),
crs = 4326
)
blaeu::map(style = blaeu::carto("voyager")) |>
blaeu::map_source(example_data, id = "quakes") |>
blaeu::map_layer(
id = "pts",
source = "quakes",
type = "circle",
# blaeu includes `paint_*` functions that make it
# easy to define how your layer should be visualized
paint = paint_circle(
# MapLibre GL expressions are supported by using
# R Lists in place of JS Arrays
color = c(
list(
"interpolate",
list("linear"),
list("get", "mag")
),
rbind(
as.list(seq(from = 0, to = 5)),
as.list(substr(viridisLite::inferno(6), 1, 7))
)
),
blur = 0.2,
radius = list("^", list("get", "mag"), 1.25)
),
# Popups are easy to create if only simple HTML is needed.
# Data properties can be included via string interpolation
# by using `${VARNAME}`, where VARNAME is the property.
popup_text = "Magnitude: ${mag}"
)
All MapLibre GL layers are supported, including fill extrusions:
blaeu::map_source(
sf::st_transform(
sf::read_sf(system.file("gpkg/nc.gpkg", package = "sf")),
4326
),
id = "nc"
) |>
blaeu::map_layer(
id = "b",
source = "nc",
type = "fill-extrusion",
paint = paint_fill_extrusion(
height = list("get", "BIR79"),
color = list(
"interpolate",
list("linear"),
list("get", "BIR79"),
0,
"#edf8fb",
319,
"#b2e2e2",
1308,
"#66c2a4",
2636,
"#2ca25f",
4989,
"#006d2c"
)
),
popup_text = "Number of Births (1979): ${BIR79}"
)
PMTiles Support
blaeu also has support for PMTiles:
blaeu::map_source(
x = "https://some/url/to/tiles.pmtiles",
type = "pmtiles",
id = "my-pmtiles-source",
# Maxzoom must be specified, otherwise
# the features will disappear after
# passing the maximum zoom
maxzoom = 10
) |>
blaeu::map_layer(
id = "my-pmtiles-layer",
source = "my-pmtiles-source",
source_layer = "my-pmtiles-source-layer",
type = "line",
paint = blaeu::paint_line(color = "blue")
)
Development
blaeu uses:
- TypeScript in place of Javascript,
- yarn for package management,
- Vite for building/bundling.
All TS code is located within the typescript/ directory.
To build out the current TS code, navigate to the typescript/
directory and run:
yarn build
This will build, bundle, and push the TS code to
inst/htmlwidgets/blaeu.js, which is the primary interface to R's
HTMLWidgets package.
License
blaeu itself is MIT-licensed.
However, MapLibre GL has a 3-Clause BSD license. Its license and dependency licenses are found here.