BEGIN:VCALENDAR VERSION:2.0 PRODID:-//pretalx//talks.osgeo.org//foss4g-2026//speaker//TFSA8P BEGIN:VTIMEZONE TZID:JST BEGIN:STANDARD DTSTART:20000101T000000 RRULE:FREQ=YEARLY;BYMONTH=1 TZNAME:JST TZOFFSETFROM:+0900 TZOFFSETTO:+0900 END:STANDARD END:VTIMEZONE BEGIN:VEVENT UID:pretalx-foss4g-2026-CGR8ML@talks.osgeo.org DTSTART;TZID=JST:20260901T160000 DTEND;TZID=JST:20260901T163000 DESCRIPTION:Introduction\nGrasslands historically occupied a substantially larger portion of the Japanese landscape than they do today. In western Ja pan\, traditional tatara iron production—a pre-industrial smelting techn ology that used iron sand and charcoal in clay furnaces—has frequently b een associated with the persistence of grassland landscapes. Historical na rratives often portray these open landscapes as products of the massive fo rest clearance and charcoal extraction that iron production required. Earl y ecological studies reinforced this interpretation: Ito (1962) noted a co rrespondence between the spatial distribution of tatara production areas a nd grassland occurrence in the Chūgoku region\, a pattern that has since been widely cited as evidence of a direct causal relationship. Despite the persistence of this interpretation\, it has rarely been subjected to rigo rous quantitative examination using spatially explicit data. This study ex amines the spatial relationship between tatara iron production sites and g rassland distribution in Tottori Prefecture\, western Japan\, using an int egrated open geospatial analysis workflow built entirely from open-source tools and publicly available datasets.\n\nStudy area and Data\nThe study a rea\, Tottori Prefecture\, occupies the northern slope of the Chūgoku Mou ntains and was historically one of the active tatara iron production regio ns in Japan. The prefecture's geology is dominated by granitic formations in the west and center\, with distinct volcanic deposits around the Daisen volcano in the northwest. Three major river basins—the Sendai\, Tenjin and Hino river systems—organize the mountainous landscape into hydrologi cally distinct units.\nThe analysis integrates three classes of data. Gras sland area was derived from municipality-level statistics in the 1950 Worl d Agricultural Census. Because the original records exist only as printed statistical tables\, a structured digitization protocol was developed usin g AI-assisted table extraction\, converting scanned census pages to machin e-readable CSV format. Tatara iron production site locations were compiled from the Tottori Prefecture WebGIS cultural heritage database. Raw spatia l data were extracted via browser developer tools and processed into struc tured point data using Python\, then aggregated to municipality counts usi ng spatial joins in QGIS 3.40. Environmental variables were constructed fr om open geospatial datasets\, including the 1:200\,000 seamless geological map of Japan\, the national hydrological grid dataset\, and DEM data from which terrain indicators including elevation\, slope\, and curvature were derived.\n\nAnalysis Methods\nSpatial data processing and analysis were c onducted using Python-based open-source libraries. GeoPandas was used for vector data integration and spatial joins. Terrain derivatives were comput ed from DEM data using rasterio and scipy\, with zonal statistics aggregat ed at the municipality level via rasterstats. All vector data were managed in GeoPackage and FlatGeobuf formats. Statistical modelling was implement ed using statsmodels and scikit-learn.\nThe analysis proceeded in three st ages. First\, ordinary least squares regression models were estimated to a ssess the relationship between environmental variables and municipality-le vel grassland area\, evaluating geological entropy\, dominant basin member ship\, mean elevation\, slope\, and curvature as predictors. Second\, step wise model comparison assessed the marginal contribution of tatara site de nsity after environmental predictors were included. Third\, DBSCAN spatial clustering was applied to tatara site point data to identify geographical ly concentrated production districts and characterise their environmental context. The complete analysis code is archived on Zenodo (https://doi.org /10.5281/zenodo.19042339).\n\nResults\nTatara iron production sites exhibi t strong spatial clustering\, identifying two large production districts i n western Tottori Prefecture concentrated within the Hino River basin. The se districts correspond closely with granitic geological formations and mi d-to-high elevation zones\, consistent with the known requirements of iron -sand-based smelting for specific geological and hydrological conditions.\ nGrassland distribution is most strongly predicted by environmental variab les rather than by tatara site density. Mean elevation is the most consist ent predictor across model specifications. When tatara site counts are add ed to environmental models\, the improvement in explanatory power is modes t. The interaction term between tatara count and slope gradient is statist ically significant and negative: municipalities with many tatara sites but steeper terrain show a weaker association with grassland area. This sugge sts that iron production promoted grassland formation primarily in accessi ble mid-elevation areas\, while in steeper terrain the same activities rel ied more directly on adjacent forest without generating the open landscape s associated with grassland land use.\n\nDiscussion\nThese findings sugges t that the long-standing narrative associating tatara iron production with grassland landscapes requires qualification. Both phenomena appear to hav e developed within similar environmental opportunity spaces defined by geo logy\, basin structure\, and topography. From the perspective of cultural evolution and niche construction theory\, tatara iron production can be in terpreted as a technological strategy adapted to a particular ecological n iche\, in which the apparent correlation between industrial sites and gras sland landscapes arises partly from shared environmental constraints rathe r than from direct landscape transformation alone.\nFrom a methodological standpoint\, the study demonstrates that open geospatial workflows combini ng QGIS\, GeoPandas\, rasterio\, rasterstats\, and statsmodels can support rigorous historical landscape analysis. The integration of AI-assisted di gitization\, spatial data standardization\, and reproducible statistical m odelling within a single transparent workflow illustrates the practical po tential of the open geospatial ecosystem for environmental history researc h. The approach is transferable to other historical industrial landscapes where documentary and archaeological data can be combined with environment al geospatial datasets to re-examine inherited interpretations of landscap e change. DTSTAMP:20260717T225748Z LOCATION:Cosmos2 SUMMARY:Examining the Relationship Between Tatara Iron Production and Grass land Distribution in Western Japan: An Open Geospatial Approach to Histori cal Landscape Analysis - Nobusuke Iwasaki\, Ayaka Onohara\, Takatora Bito URL:https://talks.osgeo.org/foss4g-2026/talk/CGR8ML/ END:VEVENT END:VCALENDAR