Harmonisation of 3D geodata : a prerequisite for a digital information flow for applications in the planning and building sector

Sammanfattning: Data harmonisation is a prerequisite for smart cities, for a more efficient information flow in the planning and building process and for many applications in the urban environment. Ideally, data harmonisation will result in a digital information flow that include information from the whole lifecycle of a feature, for example for buildings, roads and tunnels. All actors and applications involved in this process should be able to retrieve the information they require. This in turn contributes among others to the development of more sustainable cities and to reduce the shortage of housing, which is an issue in many urban areas around the world. There are still many obstacles to overcome before such well-functioning digital information flow can be achieved. In this thesis harmonisation of geographic data is studied from different technical perspectives, that is data harmonisation between geographic levels, between hierarchic structures, and over time.Standards for geographic data often focuses primarily on a certain geographic level. Examples of this are the INSPIRE directive with the main focus on cross-border applications at a European level; and the Swedish water system standard that has a national focus. That is, there are no harmonisation between the geographic levels. In Paper I we extended the INSPIRE specification for hydrography with all additional information in the Swedish water system standard to evaluate if this would achieve a more harmonised information exchange between geographic levels from both a user and a data provider perspective.Papers II – VI have a focus on 3D building information in the planning and building process and on how the digital information flow within this process can be improved for urban environment applications. 3D building information is an important part of this process and much would be gained if digital standardised information is easily available throughout the lifecycle of the building. In Paper II we evaluated the consequences of having similar but not identical definitions in standards that are related. In Paper III we created and evaluated whether guidelines could contribute to a more uniform creation of datasets, regardless of which data source is used. Paper IV is devoted to a proposal to a national building standard. It is based on national requirements and international standards and an evaluation is performed to see if this could contribute to a more uniform management of 3D city models within a country. Paper V evaluated if currently available versioning methods for 3D city models can fulfil requirements from applications in the planning and building process, and if all versioning methods are suitable for all purposes. Finally, in Paper VI we evaluated what is required and what are the issues that must be solved before versioning methods for 3D city models are used in practice, as versioning methods currently are available, but are rarely used.To conclude, this thesis has described, developed and evaluated how harmonisation of geographic data can improve the digital information flow. The main focus was on 3D building information in the planning and building process, but most of the findings are also applicable on other types of information, especially on 3D city models and on other man-made themes such as roads, tunnels and bridges. The results give an increased understanding about issues that must be solved to achieve an efficient digital flow of geographic information. It also points out the importance of performing detailed requirements analyses on application needs before implementation and that the usage of guidelines can contribute to a more streamlined usage of standards.