Streaming CityJSON datasets

Journal article (2024)

Authors

H. Ledoux Urban Data Science - Architecture and the Built Environment
G. Stavropoulou Urban Data Science - Architecture and the Built Environment
B. Dukai 3DGI
Research Group
Urban Data Science (Architecture and the Built Environment) (TU Delft)
More Info
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Published Date

2024

Language

English

Faculty

Architecture and the Built Environment

Department

Urbanism

Research Group

Urban Data Science

Abstract

We introduce CityJSON Text Sequences (CityJSONSeq in short), a format based on CityJSON and JSON Text Sequences. CityJSONSeq was added to the CityJSON specifications version 2.0 to allow us to stream very large 3D city models. The main idea is to decompose a CityJSON dataset into its individual city objects (each building, each tree, etc.) and create several independent JSON objects of a newly defined type: CityJSONFeature. We elaborate on the engineering decisions that were taken to develop CityJSONSeq, we present the open-source software we have developed to convert to and from CityJSONSeq, and we discuss different aspects of the new format, eg filesize, usability, memory footprint, etc. For several use-cases, we consider CityJSONSeq to be a better format than CityJSON because: (1) once serialised it is about 10% more compact; (2) it takes an order of magnitude less time to process; and (3) it uses significantly less memory.