How to Complete Japan’s Building Mapping in One Year? Strategies for Integrating PLATEAU Data into OSM (sotm2025)

Since 2020, Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has led Project PLATEAU, releasing 3D city models in CityGML format. By 2025, over 236 municipalities have published building datasets compatible with the Open Database License (ODbL), suitable for integration into OpenStreetMap (OSM). Since 2022, OpenStreetMap Japan volunteers have imported PLATEAU’s Level of Detail 1 (LOD1) building data into OSM, completing imports for 13 cities as of May 2025. Despite these efforts, only about 62% of Japan’s estimated 38 million building polygons are mapped in OSM. This presentation proposes a roadmap to complete Japan’s building mapping within one year, focusing on optimizing PLATEAU data imports, ensuring data consistency, and strengthening community collaboration. — Strategies for Integrating PLATEAU Data into OpenStreetMap Since 2020, Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has spearheaded Project PLATEAU, a national initiative to develop and openly release 3D city models in CityGML format. As of 2025, over 236 municipalities have published detailed building datasets, which are compatible with the Open Database License (ODbL) and suitable for integration into OpenStreetMap (OSM). These semantically rich and high-precision datasets hold significant potential for applications in urban planning, academic research, and civic technology. Building upon previous presentations at State of the Map conferences, this talk outlines the progress made since 2022 by volunteers from OpenStreetMap Japan in importing PLATEAU’s Level of Detail 1 (LOD1) building data into OSM. As of May 2025, imports have been completed for 13 cities. In addition to these imports, numerous volunteer mappers continue to enhance OSM’s building data through aerial imagery tracing and other methods. Despite these efforts, only approximately 62% of Japan’s estimated 38 million building polygons are currently mapped in OSM, leaving about 14 million polygons—38%—yet to be integrated. Addressing this gap necessitates a clear numerical target and a strategic approach. This presentation sets forth an ambitious yet achievable goal: to complete the mapping of Japan’s building data within one year. We will provide a quantitative analysis of current progress and delineate a roadmap to achieve this objective. Key strategies include optimizing the importation of PLATEAU data, ensuring data consistency between PLATEAU and OSM, and strengthening collaboration within the mapping community. By sharing these insights and methodologies, we aim to accelerate the integration of PLATEAU data into OSM and to serve as a model for other countries seeking to enhance their building mapping efforts. Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/ about this event: https://2025.stateofthemap.org/sessions/N89YSU/