Gridded Datasets for Japan: Total, Male, and Female Populations from 2001-2020

Japan is a highly urbanized and severely aging society. In an aging society, chronic disease and disability are prevalent, and the population is sensitive to environmental issues and climate change. To identify the effects of population changes, formulate population and public health policies, and assist environmental projects, a high-resolution and accurate gridded population dataset is highly desirable. To provide basic data for research in these areas, we created an open access annual dataset from 2001 to 2020 containing the total, male, and female population counts in each grid at a resolution of 500 m. A random forest method was employed to fill the gaps in Japan's nationwide census data collected in 2005, 2010, 2015, and 2020. The yearly population dataset was based on the 4^th-level mesh data from the Statistics Bureau of Japan to make it easy to use. The dataset is provided here along with descriptions of the data and methods used in the fitting, cross-validation, and prediction processes.