Abstract: Digital twin cities have become the mainstream technical route and development goal of the construction of new smart cities. The core of digital twin city is the City Information Model(CIM). The traditional “GIS + BIM” modeling method has obvious limitations: the object-oriented data organization method is difficult to solve the problem of data organization and aggregation due to the complexity of the object itself and the private definition of object ID. Beidou Grid Code technology (including Beidou Split Time Code) provides a spatiotemporal grid framework, which can build the global spatial digital twin grid data model. Its essence is an open big data architecture based on spatiotemporal coding, which can organize urban multi-source heterogeneous spatiotemporal data through grid association and support the CIM modeling of digital twin cities. The specific modeling process includes four steps: spatio-temporal grid coding, grid associated data, grid data loading and data-driven model. The spatio-temporal grid framework based on Beidou Grid Code has important enabling value for CIM platform.

Key words: spatio-temporal grid framework, City Information Modeling, digital twin cities