From consistency to flexibility: Handling spatial information schema thanks to a middleware in a 3D city modeling context

Twinning elements of reality gains a growing interest in support of decision-making, learning, and simulations: a single and shared model should provide a unique integrative basis for managing assets of any replica of the real world. From a technical viewpoint, sharing and opening information requires both an exchange format and a high degree of freedom and flexibility. It should allow an important number of users to manage this information, to modify it, etc. Storing and manipulating spatial information concerning the urban built context currently focuses on ensuring consistency thanks to relational databases and predefined schemas. Following a paradigm shift from a relational database to a NoSQL database, a schema validation middleware is proposed to improve the flexibility of storage by conceding a share of its consistency. The flexibility improvements thus provide users a common basis that is able to evolve all along the lifecycle of their models and applications as required for twinning things. It allows users and their applications to take advantage of new storage features such as common: versioning, partitioning, prioritization, applications profiles, etc. The middleware and their new capabilities are illustrated thanks to the CityJSON encoding and its simplified schema for a document-oriented database.