CityJSON: a compact and easy-to-use encoding of the CityGML data model

The international standard CityGML is both a data model and an exchange format to store digital 3D models of cities. While the data model is used by several cities, companies, and governments, in this paper we argue that its XML-based exchange format has several drawbacks. These drawbacks mean that it is difficult for developers to implement...

val3dity: validation of 3D GIS primitives according to the international standards

The validity of 3D primitives in 3D GIS datasets is often a prerequisite for using them in simulation and decision-making software, e.g. visibility analysis, noise pollution assessment, and energy estimation. However, while agreed definitions exist (in the international standard ISO19107), most software vendors ignore them and implement simpler...

CityGML Application Domain Extension (ADE): overview of developments

The Application Domain Extension (ADE) is a built-in mechanism of CityGML to augment its data model with additional concepts required by particular use cases. The goal of this paper is to provide an overview of the ADE mechanism and a literature review of developments since its introduction a decade ago. The discovery of publications found that...

Formalisation of the level of detail in 3D city modelling

The level of detail in 3D city modelling, despite its usefulness and importance, is still an ambiguous and undefined term. It is used for the communication of how thoroughly real-world features have been acquired and modelled, as we demonstrate in this paper. Its definitions vary greatly between practitioners, standards and institutions. We...