Comparison of Standard- and Proprietary-Based Approaches to Detailed 3D City Mapping

3D information is essential for a number of applications used daily in various domains such as facility management, including energy management, urban planning, telecommunications, and safety and security, etc. This paper is devoted to 3D modelling at the level of city districts with the campus and buildings modelling use case. Different methods and technologies commonly used in this area are first analysed and discussed. Emphasis is placed on the comparison of the standardized approach, represented by the CityGML (City Geography Markup Language), and proprietary technologies (developed by Masaryk University as a part of facility management called the Building Documentation System). This comparison is demonstrated on a sample 3D model of the Faculty of Science at Masaryk University in Brno, the Czech Republic, situated on Kotlařska Street. Both types of 3D models were developed while focusing on their benefits and limitations. The conclusions drawn from the study present a concept of 3D city mapping with an emphasis on where the use of CityGML reaches its limits and the point from which proprietary-based solutions should be implemented. Recommendations on future CityGML development are given at the end of the article. Some of our current recommendations have been incorporated into version 2.0 of the CityGML implementation specification by the Open Geospatial Consortium. Furthermore, we are participating in the ongoing development of CityGML version 3.0.