Future Swedish 3D City Models—Specifications, Test Data, and Evaluation

Abstract

Three-dimensional city models are increasingly being used for analyses and simulations. To enable such applications, it is necessary to standardise semantically richer city models and, in some cases, to connect the models with external data sources. In this study, we describe the development of a new Swedish specification for 3D city models, denoted as 3CIM, which is a joint effort between the three largest cities in Sweden—Stockholm, Gothenburg, and Malmö. Technically, 3CIM is an extension of the OGC standard CityGML 2.0, implemented as an application domain extension (ADE). The ADE is semantically thin, mainly extending CityGML 2.0 to harmonise with national standards; in contrast, 3CIM is mainly based on linkages to external databases, registers, and operational systems for the semantic part. The current version, 3CIM 1.0, includes various themes, including Bridge, Building, Utility, City Furniture, Transportation, Tunnel, Vegetation, and Water. Three test areas were created with 3CIM data, one in each city. These data were evaluated in several use-cases, including visualisation as well as daylight, noise, and flooding simulations. The conclusion from these use-cases is that the 3CIM data, together with the linked external data sources, allow for the inclusion of the necessary information for the visualisation and simulations, but extract, transform, and load (ETL) processes are required to tailor the input data. The next step is to implement 3CIM within the three cities, which will entail several challenges, as discussed at the end of the paper.

3D LAND-MARINE PROPERTIES ADMINISTRATION IN THE CONTEXT OF SEA LEVEL RISE (SLR) – ISSUES & CHALLENGES

“…Recent reports suggest that 3D city model and digital twins deal with large data which requires substantial database management capability, thus, issues such as geometry of different objects within 3D models (for city models and digital twins) needs to be addressed. Janecka and Khaki (2016) related to the 3D cadastre objects and on 4D data; Uggla et al (2023) more on the quality aspect of 3D city models. However, not much is being reported for the digital twins especially related to the land and marine objects.…”

The Geospatial Crowd: Emerging Trends and Challenges in Crowdsourced Spatial Analytics

“…This technology will make it possible to build complex 3D models of cities, which will offer experiences that are designed for urban planning and management. By using the visualization of navigating around these digital twins, users can analyze the complexity of the details of energy networks, traffic flow, and urban planning, in order to improve the decision-making processes [33]. In addition, these technologies are used not only to evaluate the infrastructure but also to adapt new methods to manage it.…”

“…For example, the integration of real-time data obtained from several sensors will facilitate efficient resource allocation and promote proactive decision-making [32]. Furthermore, 3D GIS and digital twins can discover hidden patterns and connections that will transform our knowledge and management of urban and environmental systems, thereby making a substantial contribution to the fields of crowdsourcing and spatial data analytics [33,34].…”

Research and Application of Urban 3D Modeling Technology in Virtual Reality Scenes

“…Virtual battlefields, virtual cities, digital cities, and even "digital earth" are all applications of virtual reality technology. Virtual reality technology will revolutionize many traditional sectors and industries [8].…”