CityJSON offers an easy-to-use alternative to the GML encoding of CityGML 2.0 for the storage and exchange of 3D city models.
CityJSON is a JSON-based encoding for a subset of the OGC CityGML data model (version 2.0.0). CityJSON defines ways to describe most of the common 3D features and objects found in cities (such as buildings, roads, rivers, bridges, vegetation, and city furniture) and the relationships between them. It also defines different standard levels of detail (LoDs) for the 3D objects, which allows different resolutions of objects for different applications and purposes.
A CityJSON file describes both the geometry (an object’s form) and the semantics (an object’s function) of the features in a given area, such as the buildings, roads, rivers, vegetation, and city furniture.
The aim of CityJSON is to offer an alternative to the GML encoding of CityGML, which can be verbose and complex to read and manipulate. CityJSON aims at being easy-to-use, both for reading datasets and for creating them. It was designed with programmers in mind, so that tools and APIs supporting it can be quickly built.