National Land Numerical Information in QGIS

Introduction

National Land Numerical Information is an open data platform that provides a wide range of geographic information about Japan. The data you download there is easy to use in GIS software such as QGIS. It spans many fields, so most people who use GIS regularly have probably used it.

This article explains how to download GIS data from National Land Numerical Information and how to display that data in QGIS.

What is National Land Numerical Information? Japan's open data platform

National Land Numerical Information is a download site (platform) for open data that systematically compiles geographic information about Japan, provided by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT). It offers a variety of GIS data on the national land, including terrain, land use, and public facilities.

National Land Numerical Information covers five broad categories (Source: National Land Numerical Information Download Service).

The site provides data free of charge in principle, but whether you can use the data commercially differs by dataset, so check each time.

How to download GIS data and display it in QGIS

Go to the National Land Numerical Information Download Service

To download GIS data, first go to the National Land Numerical Information Download Service. The site sorts nationwide geospatial information into categories, so the data you need is easy to find.

Select and review the data

When you find the dataset you need, select it. This article uses Administrative Area (Polygon) (行政区域（ポリゴン）) under 2. Policy Areas (2. 政策区域) → Administrative Regions (行政地域).

The download page lists various information, such as the update history, the contents (a description of the data), how the data was created, the terms of use for the data, and the coordinate system.

When you use National Land Numerical Information data, the item to check above all is the terms of use for the data (このデータの使用許諾条件). Whether commercial use is allowed differs by dataset, so always check the terms of use for the dataset.

For example, the page for the “Railway Data” states “Fiscal year 2020 and later: based on the applicable terms of use; other than the above: commercial use allowed,” so commercial use is basically allowed.

However, the “Railway Time-Series Data” is marked “non-commercial,” so you cannot use it commercially.

The “Administrative Area Data” downloaded in this article is described as “open data under the Content Terms of Use of the National Land Numerical Information Download Service (compliant with the Government Standard Terms of Use),” so read the “Content Terms of Use of the National Land Numerical Information Download Service” page before you use the data.

Download the data

Scroll down the Administrative Area Data page to find the “Select data to download” section (ダウンロードするデータの選択). The Administrative Area Data comes in two units, “nationwide/regional” and “prefecture,” so select the unit you need. This example selects Aichi Prefecture.

The page scrolls automatically and shows the row for the area you selected. Click the Download button (ダウンロード) at the far right of that row.

A user survey for the National Land Numerical Information Download Service appears on the screen.

You do not have to answer the survey for every download, but your answers serve as a reference for the future development of National Land Numerical Information data, so it is a good idea to respond.

Submit the survey, or click Skip (スキップする) at the bottom right. The download starts.

Check the data

Unzip the downloaded ZIP file of GIS data and look inside. The files differ by dataset and by the year the data was compiled. The Administrative Area Data contains the following.

Here is what each file contains.

The site publishes many datasets as Shapefile. GeoJSON is a data format used mainly in web GIS. QGIS can display GeoJSON too, but large datasets may affect performance.

To learn more about vector data formats, see this article.

Add the data to QGIS

Now display the downloaded data in QGIS. Some datasets are not provided as GeoJSON, so this article uses the Shapefile. Drag and drop the SHP file into QGIS.

The administrative area data for Aichi Prefecture appears on the map canvas.

How to read the attribute table of National Land Numerical Information data

How to check attribute names

Next, look at the attribute table. Right-click the layer in the Layers panel and click Open Attribute Table.

The attribute names in the attribute table are made up of letters and numbers, such as “N03-001” to “N03-007.”

To find out what an attribute name means, check the download page of each dataset. On the download page of the Administrative Area Data used here, the attribute information section at the top lists each attribute name and its description.

To find out what an attribute name means, check the attribute information (属性情報) on the download page of each dataset.

How to check attribute values

In the N03_007 column (national local government code) of the Administrative Area Data, the values are stored as codes from a code list.

As in this example, some attributes in National Land Numerical Information data are stored as codes from a code list.

To find out what a value means, do the same as above and check the attribute information on the download page of each dataset. The row for the attribute has a link such as Code List (コードリスト). Click it.

The code list for “Nationwide Local Governments” is an Excel file. Use it to look up the municipality name and other details for each code.

As you can see, National Land Numerical Information data may write attribute names and values as codes, so check what the codes mean on the download page of the dataset.

Conclusion

National Land Numerical Information provides a wide range of geospatial data about Japan free of charge, and you can easily display and use it in QGIS. However, terms of use such as whether commercial use is allowed differ by dataset, and attributes are written as codes, so check this information in advance as you work.