Building and roof type classification on 3D city models

In a rapidly evolving digital landscape, 3D city models have become more accurate and complex. Despite their widespread availability of open-source 3D city model datasets, these invaluable resources remain underutilized. Our primary goal centers on the classification of building and roof types. For our client, Spotr, our work directly impacts on...

CJDB - A simple and efficient data model to store CityJSON in a database

A 3D city model uses three-dimensional geometries to represent and model urban environments, in which the building model is the key feature. With the development of computer and data collection technologies, 3D city models are gaining growing capacities regarding storing rich information. This makes 3D city models more potentially useful than...

Development and Testing of the CityJSON Energy Extension for Space Heating Demand Calculation

3D city models are frequently used to acquire and store energy-related information of buildings to be used in energy applications, such as solar potential analyses and energy demand calculations. In this context, the most common data model is CityGML, which provides an application domain extension called the Energy ADE to store energy-related...

CityJSON in combination with MongoDB, PostgreSQL and GraphQL

CityJSON is a JSON-based encoding for a subset of the CityGML data model and an alternative to the CityGML exchange-format. This new encoding reduces the data size and simplifies the usage. These files can be stored in relational and NoSQL databases. Relational and NoSQL databases have integrated JSON. CityJSON has therefore the potential to be...

An integrative workflow for 3D city model versioning

3D city models are continuously becoming more popular among practitioners due to the volume and versatility of information they contain, which makes them suitable to be used in various applications. However, there is no mechanism to allow maintaining them updated at the same pace that cities evolve, or when error correction is necessary,...

CityJSON: does (file) size matter?

The possibilities of 3D city models for the analysis of the built environment are increasingly explored, and there is a continuous development in improvements on their inner workings. They are also used more often on the web, for example for visualisation but it is also possible to query, analyse, and edit data in this way. In this case, the...

Modelling different levels of detail of roads and intersections in 3D city models

In the last two decades there has been a steady rise in the gathering and use of 3D geo-information. A common way to store and use 3D data is by using 3D city models. In 3D city models, geo-information can be stored at different levels of detail. CityGML, the most commonly used data model and encoding for 3D city models, uses five levels of...