LICENSE

The Parquet files in this directory are adapted from 全国の人流オープンデータ
(1km メッシュ、市区町村単位発地別), published by the Ministry of Land,
Infrastructure, Transport and Tourism (MLIT) of Japan:

  https://www.geospatial.jp/ckan/dataset/mlit-1km-fromto

They are used under 全国の人流オープンデータ利用規約 (license.pdf in this
directory, 令和3年1月27日), which follows the Government of Japan Standard Terms
of Use (Version 2.0) and is compatible with CC BY 4.0
(https://creativecommons.org/licenses/by/4.0/legalcode.ja). The terms allow
copying, public transmission and adaptation, including commercial use.

Credit, as the terms require (出典の記載):

  出典：「全国の人流オープンデータ」（国土交通省）（https://www.geospatial.jp/ckan/dataset/mlit-1km-fromto）
  「全国の人流オープンデータ」（国土交通省）（https://www.geospatial.jp/ckan/dataset/mlit-1km-fromto）を加工して作成

The files were changed from the originals (2026-09-29):

  - The CSVs inside the nested zip files were combined into one Parquet file
    per kind; for monthly_mdp_mesh1km and monthly_fromto_city, all 47
    prefectures and every month (2019-01 to 2021-12) are in one file.
  - population was turned into an integer; every other column is kept as the
    text of the CSV (codes keep their leading zeros).
  - attribute_mesh1km and the masters have both the 2019 and the 2020 file of
    the source, told apart by an added version column. Only the UTF-8 masters
    were used (the Shift_JIS ones hold the same data).
  - attribute_mesh1km has an added geometry column (the rectangle of lon_min,
    lat_min, lon_max, lat_max, WGS 84).
  - Rows were sorted; values were not changed.

license.pdf and opendatadefinition.pdf are the source's own files, unchanged.