3D modelling of the city is facilitating citywide mapping, improved communication and faster decision making
Digital mapping of the City of Helsinki began in 1982, while the first 3D digital model of an area of the city was created as part of an architectural competition in 1987. The city is on target to realise a fully detailed 3D model by 2013.
The coastline and numerous islands that lie within the city boundary pose a particular challenge, and the complicated nature of the local terrain has resulted in a modelling project that is both extensive and comprehensive. Laser scanning now covers one-third of the city each year, so the raw data is never more than 3 years old.
The city surveying department gathers data and creates basic maps and models, which are passed to the city planning department. Sections of the model begin as outline 2D sketches, and then blocks are placed over the map. According to Jarmo Suomisto, IT manager incharge of workflows within the department, the use of MicroStation throughout the organisation has helped to revise and refine the department”s myriad processes to implement streamlined workflows.
The system has made it possible to model a significant development area within just half a day. This provides an almost instant opportunity to visualise individual urban spaces and how they might connect with each other. The Oracle planning database is so large that it is broken down into separate entities and managed using ProjectWise, Bentley”s project team collaboration software, which the city uses across several departments.
ACCURATE SPATIAL ANALYSIS
Precision is vital if the impact of new buildings is to be assessed. With Bentley products, users can achieve accuracies of less than one metre, with error margins of 10-15 cm in detailed modelling. This enables professionals in other disciplines to understand the possible consequences of proposed developments such as the threat of rising water levels in low-lying areas or critical vistas and visual corridors.
EFFICIENT REGULATORY PROCESSES
In Helsinki, all building construction requires a permit and each permit request has to be supported by a detailed plan of the city, based on the 3D model. It is clear thus that the 3D city model will have a future role in the regulatory review process.
Helsinki Energy, which is responsible for district heating infrastructure, now references the 3D city model data while planning its networks. In addition, communications service providers in Helsinki also reference the 3D city model when planning upgrades and extensions to their networks.
CLEAR PUBLIC COMMUNICATION
During public consultations, all communication with residents features the city model. For city planners, this means that approvals can be granted much more quickly than before. For example, a process that earlier took 2.5 years may now be completed within 1.5 years. That represents huge cost savings, because an office or retail development would generate income and local taxes up to one year earlier.
The 3D city model is also improving transparency as the basic models and renderings for all proposed and approved developments are available on the City of Helsinki website. The 3D models have been plotted out for presentation to the public, both in Helsinki and overseas.