Global demand for geospatial data is rising, but countries adopt 3D city models at very different stages. This talk explores Japan's Project PLATEAU in its mature phase and shares what we learned from Ukraine's reconstruction-driven adoption, with additional insights from Thailand and Peru.

The global demand for geospatial data is rapidly increasing across domains such as urban planning, disaster management, infrastructure monitoring, and climate adaptation. In response, many governments and cities have begun developing 3D city models as the next generation of geospatial infrastructure. However, the global landscape is far from uniform. Adoption unfolds in many different forms, shaped by each region's data, institutions, and use cases.

Japan represents one of the more advanced cases. Led by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), Project PLATEAU has developed and openly published 3D city models across numerous municipalities, becoming a reference for how national-scale, open 3D city data can be built. Eukarya Inc., a company involved in Project PLATEAU and developer of the open Web GIS platform Re:Earth, has been working with the Japanese government and international development agencies to explore how similar initiatives can take root elsewhere.

This talk shares field experiences from three very different contexts (Thailand, Ukraine, and Peru), where we set out to adapt PLATEAU's open approach to different local needs, institutions, and implementation conditions. Our initial assumption was that grouping regions by 3D city model maturity would let us match strategies to starting points. That assumption didn't survive contact with the field.

What we found instead was that sustainable implementation depended on four conditions, regardless of maturity:

(1) local needs, whether there is a real problem to solve first;

(2) implementation conditions, whether governance, standards, workflows, and technology can be aligned;

(3) investment rationale, whether there is a visible reason to fund it;

and (4) local sustainability, whether local actors can operate, update, and expand it over time. Ukraine's experience,

in particular, illustrates how 3D data becomes useful only when standards, governance, workflows, and local capacity are designed around it, and how adoption unfolds through stages of technology transfer, ecosystem co-development, and sustainable local operation.

The talk closes by discussing what this means for the FOSS4G community: how open technologies can support sustainable 3D city model adoption and help move projects from technology adoption toward ecosystem co-development. The session is intended for a wide audience involved in the geospatial ecosystem, including government agencies, technology providers, researchers, municipalities, and community members, and aims to foster discussion on how the global FOSS4G community can co-develop geospatial ecosystems that local actors can own, operate, and evolve.