Web-based management and visualization of massive 3D city models

by Claus Nagel

The usage and importance of virtual 3D city models is steadily increasing in diverse application areas such as 3D cadastre, urban planning and simulation or disaster management. Cities and users therefore need an open, vendor-neutral and standards-based platform for the management and visualization of 3D city models as basis for the numerous applications and digital systems consuming the 3D city model data. The international OGC standard for the representation, storage and exchange of virtual 3D city models used by many cities worldwide is CityGML. It is a GML3 application schema to represent the 3D geometry, 3D topology, semantics and appearance of urban features (e.g., buildings, vegetation, traffic, terrain). Due to the rich semantic information, CityGML-based models can not only be used for visualization purposes but also for thematic analysis.

This talk presents how to handle and visualize massive 3D city models based on an open source 3D GIS stack. It will be shown how to manage CityGML-based 3D city models using the open source 3D City Database (http://www.3dcitydb.org). Moreover, an open OGC Web Feature Service (WFS) interface to the database for querying and updating the city model is presented. In addition, we will show how to automatically prepare massive 3D city models from the database for the efficient visualization using the WebGL-based 3D web-globe Cesium and the open 3D Tiles specification. In order to make the semantic city information available in the visualization, we will propose an extension to 3D Tiles. Finally, we will showcase a web-based viewer that enables the exploration of massive 3D city models and urban planning scenarios.