Streaming CityJSON datasets

Journal Article (2024)
Author(s)

Hugo Ledoux (TU Delft - Urban Data Science)

Gina Stavropoulou (TU Delft - Urban Data Science)

B. Dukai (3DGI)

Research Group
Urban Data Science
DOI related publication
https://doi.org/10.5194/isprs-archives-XLVIII-4-W11-2024-57-2024
More Info
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Publication Year
2024
Language
English
Research Group
Urban Data Science
Issue number
4/W11-2024
Volume number
48
Pages (from-to)
57-63
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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.