Suchergebnisse

Historical land use records are valuable information for biodiversity protection, disaster management, rural area planning and many other uses. The Rapid Survey Maps (RSM) that were surveyed in the 1880' s (early Meiji Era), are the first modern cartographical map series of Japan and important sources of information on traditional land use in early modern Japan. We had been analyzing these maps based on polygon data and raster based Web-GIS System to disseminate the Rapid Survey Maps using FOSS4G, but, these are difficult to apply for quantitative analyses of land use change. Thus, we developed a grid based land use database using QGIS and PostGIS, and published the database using GitHub. First, we developed a land use data input system consisting of a client and server. The client was developed using QGIS API and the server was a PostGIS database. Point data as a 100 m grid was stored in the PostGIS server and land use category underneath each point was input using the QGIS application. About 1,400 thousand records (70%) have already been inputted. Error of grid based land use data is less than 1% compared with vector based land use data. We analyzed land use change from the 1880' s to 1975' s. The most significant difference between the 1880' s and 1970' s is the area of urban land use and " rough land" such as grassland and bush. Urban area increased remarkably and grassland area almost disappeared. That does not mean grassland changed to urban area. Most grassland changed to agricultural land uses and forest, and urban area was formerly mainly agricultural land use and forest. Some inputted data have been copied to GeoJSON and uploaded to GitHub as open data (Creative Commons BY 2.1 Japan). A tentative data browsing site was constructed with Leaflet. In this site, it is possible to compare point type land use data in the 1880' s and present topographic map/RSM raster data. We hope that this database contributes to not only academic research, but also business, government, and public interest.