— Strategies for Integrating PLATEAU Data into OpenStreetMap

Since 2020, Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has led Project PLATEAU, developing and releasing 3D city models in CityGML format. By 2025, over 236 municipalities have published detailed building datasets compatible with the Open Database License (ODbL), making them suitable for integration into OpenStreetMap (OSM). These high-precision, semantically rich datasets are valuable for urban planning, research, and civic technology.

Building upon previous FOSS4G and SotM presentations, this talk highlights the progress made since 2022 by OpenStreetMap Japan volunteers 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 about 62% of Japan’s estimated 38 million building polygons are currently mapped in OSM, leaving approximately 14 million polygons (38%) yet to be integrated. Addressing this gap requires a clear numerical target and a strategic approach.

This presentation outlines an ambitious yet achievable goal: to complete the mapping of Japan’s building data using the CityGML-OSM converter within one year. We will provide a quantitative analysis of current progress and outline 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 serve as a model for other countries seeking to enhance their building mapping efforts.