The aim of this study is to understand the geographical diffusion of COVID-19 epidemic waves caused by SARS-CoV-2 Omicron variant in Japan from January 2022 to May 2023. We applied the diffusion non-negative matrix factorisation (diffusion-NMF), which combines a nonnegative matrix factorisation with a spatial weight matrix constructed from human mobility between prefectures, to the cumulative number of COVID-19 positive cases by prefecture. The result showed that the metropolitan centres of Tokyo, Aichi, Osaka and Fukuoka prefectures led the COVID-19 epidemic throughout Japan in the early stage of Omicron waves, followed by hierarchical diffusion to central areas in provincial regions and the no-epicentre stage in subsequent waves.

This paper reviews 1,813 academic articles on OpenStreetMap (OSM) published between 2008 and 2022, primarily in geographic information science. The study highlights OSM’s significant impact on participatory GIS research and its diverse applications beyond spatial analysis. A text analysis of the abstracts identified 10 key research topics using 100 OSM-related keywords. These topics include: (1) spatial analysis and data quality assessment, (2) system development, (3) community building and humanitarian efforts, and (4) applied research in areas like healthcare. The review reveals the multifaceted nature of OSM studies and their wide-ranging practical applications. Based on these findings, the paper suggests potential directions for future research in this field.

With reference to the “Shiga Prefecture Municipal Transition Map (1)”, old town/village boundaries in Shiga Prefecture between 1868 and 1879 were reconstructed by processing subregional polygon data from three nationwide censuses: National Census, Census of Agriculture and Forestry, and Census of Economy. In all cases based on sub-regional polygon data, more than 90% of the old town/village boundaries could be reconstructed using attribute information alone. For 10% of the old towns and villages, supplementary information was needed to reconstruct the boundaries. There was less need for supplementary information when reconstructing boundaries from the data of Census of Economy and the data of Census of Agriculture and Forestry. The old town/village boundaries created from the Census of Economy data were most similar to the shape of the town/ village boundaries in the “Shiga Prefecture Municipal Transition Map (1)”. These results suggest that the sub-regional data of the Census of Economy are the most suitable for reconstructing the old town/village boundaries of the early Meiji period in Shiga Prefecture.

This study is a data-driven research using an open excavation database with publicly available geospatial information, combined with the results of previous studies in historical disaster research and other historical materials. The target area is the site of Heian-kyo in Kyoto City, dealing with great fires in the early modern period. The excavated fire traces were analyzed on GIS by overlaying them with the reconstructed damage area of previous studies in historical geography and kasai-zu (maps of fire disaster). As a result, many of the excavated fire traces were found to be within the damage area of the previous studies, and there were points where the validity of the damage area was enhanced. However, the excavated fire traces were also found in some areas that were not included in the affected area in previous studies, suggesting that the affected area should be reconsidered.

In the regions affected by the Great East Japan Earthquake, the topography has undergone significant changes as a result of extensive reconstruction projects. The aim of this study is to evaluate the effect of post-disaster topographic changes on reducing the risk of tsunami inundation. In order to determine inundation, elevation change using DEM of after the earthquake and the present was compared to tsunami inundation depth. It was found that the reduction effect was estimated to be 3.6% in Iwate Prefecture and 5.1% in Miyagi Prefecture and the effects were higher in the inner bay and inland municipalities. Furthermore, it is crucial to prioritize tsunami evacuation plans for residents in areas that are deemed non-inundated as a result of land readjustment projects and highway embankments.