jpmap follows the same basic workflow as
usmap: plot a map, get the map data, and transform your own
coordinates into the same coordinate system.
Install the development version from GitHub:
install.packages("remotes")
remotes::install_github("yhoriuchi/jpmap")Boundary GeoPackages are large. Install the companion
jpmapdata package when you want ready-to-use boundaries, or
build local files with jpmap_build_data().
The main plotting function is plot_jpmap(). These two
calls draw empty maps without adding data, labels, colors, or other
options.
plot_jpmap("prefecture")
plot_jpmap("municipality", include = "Okinawa")The data function is jp_map(), which returns an
sf object.
prefectures <- jp_map("prefecture")
okinawa_municipalities <- jp_map("municipality", include = "Okinawa")The transform function is jpmap_transform().
places <- tribble(
~place, ~lon, ~lat,
"Tokyo", 139.767, 35.681,
"Naha", 127.681, 26.212,
"Ogasawara", 142.191, 27.094
)
places |>
jpmap_transform(output_names = c("x", "y"))
#> # A tibble: 3 × 5
#> place lon lat x y
#> <chr> <dbl> <dbl> <dbl> <dbl>
#> 1 Tokyo 140. 35.7 205212. -199414.
#> 2 Naha 128. 26.2 -683245. 657517.
#> 3 Ogasawara 142. 27.1 537219. -578089.By default, the transform moves Okinawa and Ogasawara into visible
inset locations. Use inset = FALSE for a literal projected
map, or pass a character vector such as inset = "okinawa"
to transport only selected island groups. You can also use
okinawa = FALSE or ogasawara = FALSE.
plot_jpmap() draws inset boxes by default; set
inset_boxes = FALSE to remove them. Use xlim,
ylim, x_breaks, y_breaks,
x_labels, and y_labels when you want to
customize the displayed longitude/latitude frame.