Please cite the jpmap package whenever you use it.

Horiuchi Y (2026). jpmap: Japan Maps with Insets for Okinawa and Ogasawara. Comprehensive R Archive Network (CRAN). doi:10.32614/CRAN.package.jpmap. R package version 0.1.3, https://CRAN.R-project.org/package=jpmap.

Corresponding BibTeX entry:

  @Manual{jpmap,
    title = {jpmap: Japan Maps with Insets for Okinawa and Ogasawara},
    author = {Yusaku Horiuchi},
    year = {2026},
    note = {R package version 0.1.3},
    organization = {Comprehensive R Archive Network (CRAN)},
    doi = {10.32614/CRAN.package.jpmap},
    url = {https://CRAN.R-project.org/package=jpmap},
  }