Export of the textured 3D city models 3D city models are exported to GIS formats like shapefile and geodatabase for analysis in ArcGIS 9 (ESRI Inc.), to standard CAD formats (e.g. DXF) and to the real-time format OpenFlight supporting multiple LOD for interactive visualization e.g. in TerrainView (ViewTec AG). This variability in formats increases the value of the 3D data for customers not only from the local government by allowing the use in several departments but also in a number of different systems, which legitimates the initial investment in the production of such data. Application areas for 3D city models The experience shows that 3D scenes have a greater effect in the decision making process of people than two-dimensional drawings, written text and tables with numerical information. In particular this applies for geospatial information and is the basis for a number of applications where 3D city models and 3D landmarks are used. Urban Planning Urban planning is certainly one of the most important fields of application for 3D city models. Local governments find themselves often confronted with complex decision processes about larger restructuring projects of old town areas and investment projects (e.g. a new shopping centre, commercial area, industrial site). Using a 3D city model in a state-of-the-art realtime visualization solution, all parties involved in the decision-making process can fly interactively through the virtual 3D city model. Since the realtime visualization systems support a number of CAD-formats, participating architects may place their drafts of planned projects in the 3D city model and present it to the public (Figure 4). When a new road construction is planned, an interactive 3D visualization may help to demonstrate the possible alternatives (variant planning). The impact on the natural landscape becomes most clear in the 3D virtual representation of the situation. Besides the terrain, image data and 3D city models, it is also possible to show various 3D objects like bridges. Disaster Control With the global climatic changes currently becoming apparent, a protection against natural disasters like floods is necessary in both developed and developing countries. 3D city models in combination with detailed DTM serve as a basis for numerical flood simulations (Figure 5). Using detailed 3D city models, it is possible not only predict whether parts of a city will be affected by the flood or not but also how severe the impact on the buildings will be. These simulations help to plan efficient flood protection measures.  Fig.3: 3D City Model of Los Angeles, USA. Photo-realistic textures in the Little Tokyo district. Courtesy of CyberCity 3D LLC. Fig.4:A planned power plant in the industrial park in Frankfurt, Germany. The start of construction is scheduled for the first half of 2007. Courtesy of Infraserv GmbH & Co. Höchst KG. Engineering The Central Outfall Sewer (COS) project of the City of Los Angeles Department of Public Works Bureau of Engineering, which is a part of a larger effort to rehabilitate the entire city sewer system, is a project that demonstrates the potential of 3D city models in engineering applications. The project included the creation of a geospatially accurate 3D terrain and city model along the COS path. The model included maintenance-hole structures, connecting sewers, street names, proposed construction sites and 3D buildings to name only a few. The model enables planners, engineers and decision makers to test, view and evaluate the spatial and visual impacts of changing project conditions and parameters in real time within a detailed, spatially accurate, georeferenced computer environment. Videos of the internal inspection of the sewer were integrated as hyperlinks to the corresponding location in the sewer (Figure 6). The understanding of the complex project information was improved and a successful community-outreach program including multi-media and web-streaming was achieved. The availability of the model helps the engineers to reduce the amount of time needed for field visits and therefore the internal costs. Location marketing Once an investment project like a commercial area is realized, it is important for the operator of the site to acquire customers, e.g. companies searching for a new office location. The operator may be a real estate company or a local government. As it is not only the price that governs the decision making process but also aspects like connectivity to public transport, local infrastructure and the location of the site in a larger context, an interactive realtime visualization with a 3D model is an excellent tool for business development and business location marketing. The German company Infraserv Höchst, operator of a large industrial area in Frankfurt, uses a detailed photo-realistic 3D model created by CyberCity of the industry park for the acquisition of new companies willing to settle down in the area. |