From property to governmental digital twin: the future cadastre in Switzerland

Having begun in the 1990s, the digitization of the property cadastre in Switzerland has now nearly been completed. At the same time, the cadastre of public-law restrictions on land ownership was also developed according to the C2014 concept. Today, cadastral data is an essential pillar of the national spatial data infrastructure, and is central to many governmental processes and directives. This article shows what demands the future cadastre can fulfil in the age of digital transformation.

In view of the comprehensive digitization of cadastral plans and the cadastral data that is now available in Switzerland, those involved in cadastral surveying can be proud of what has already been achieved. Ten years ago, easy access to data, whether via map services or open government data, was hardly conceivable, but today the country’s cadastre has an excellent reputation among users. They appreciate the reliability, the accuracy, the fact that it covers many requirements and the high level of up-to-dateness (with constant data updates). The reliability is reflected, among other things, by the fact that mortgage loans worth CHF 1,250 billion (against the nation’s GDP of approximately CHF 800 billion) were secured with the land register in 2023, and that only very few cases of disputed boundaries are brought before the courts.

Due to the high costs associated with data collection and the decentralized organization of the cadastral system, it was clear from the outset that data exchange between the systems was necessary. To this end, a conceptual data model was developed so that the data could be easily harmonized. Secondly, the data collection orders were linked to the obligation to deliver the data in a system-neutral format, structured according to a standardized, object-oriented data model. This ensured semantic interoperability at an early stage and initiated the change from plan-oriented thinking to structured data. The conceptual ideas were later adopted for the development of the national spatial data infrastructure (NSDI).

Added value of digital cadastre data

As a result of its wide availability and high quality, the cadastral data is now also being used as base maps for many other GIS applications. Thanks to this usage, which goes beyond the original purpose, the high investments in data collection have already paid off.

However, the data from the property cadastre is not only used for orientation purposes, i.e. as geospatial reference data. Additionally, many governmental processes today rely on the geometries of the cadastre for legally binding directives. These two examples illustrate this:

• In a building permit procedure, the authorities decide that, according to the cadastral data, the existing building may be extended by a maximum of 3.5m to maintain the prescribed boundary distance of 5m.
• An authority determines that the fees for the drainage of rainwater are calculated based on the sealed area per property. The degree of sealing is in turn derived from the land use in the cadastral data.

In other words, the cadastral data is used by various authorities as the basis for directives. The high quality and the associated high level of trust in the data enable many authorities to accept data without further clarification with the authorities responsible for the cadastral data. Therefore, those authorities have only limited influence over the actual usage of the data.

Potential for improvement and new challenges

However, 30 years after the start of the digitization of the cadastral system, it must be stated that the willingness for innovation and change in related sectors has been higher than in cadastral surveying itself. Despite methodological freedom, the same measuring and recording methods are still being used as 20 years ago. For example, drone surveying or mobile laser scanning are not used in the city of Zurich for ongoing data updates.

The authorities of the city of Zurich, at cantonal and federal level, are confronted with various challenges to sustainably secure the prosperity of society and the living space. The overarching strategies address topics such as the digital provision of government services and the promotion of innovative solutions through the broad availability of data and data-based algorithms such as artificial intelligence. In addition to increasing the effectiveness of government processes, the protection of natural resources and resilience to climate change have also been identified as key challenges.

This raises the question as to what extent the cadastre can contribute to these overarching strategies and to the ‘green-blue transformation’. The federal government, as the supreme supervisory authority for the cadastre, has taken the opportunity to develop a new vision for the cadastral data with a working group. Please note: the following developments were prepared from the perspective of the city of Zurich; they do not fully reflect the common position of the working group.

Beyond C2014: the vision of the city of Zurich

From the point of view of the city of Zurich, the cadastral system has an excellent chance of further strengthening its importance for the citizens, political administration and economy through strategic development, in view of the challenges facing today’s society. The following three pillars have been identified for the new vision.

1. The governmental digital twin

The development from property cadastre to tax cadastre to multipurpose cadastre is being supplemented by a further step: the governmental digital twin (GDT). For the GDT, the current data will be extended by the third and fourth dimensions. The advantages of the third dimension are undisputed, and the processes, technologies and algorithms for data collection and management have improved so significantly over time that the cost-benefit ratio is now appropriate. The fourth dimension facilitates the tracking of developments, which supports various simulations and the design of development scenarios. Besides the addition of these two dimensions, there will also be an expansion in terms of content. This will be consistently aligned with the needs of users and, for this purpose, there should be a new change board representing various user groups.

2. Single source of truth

In the spatial data infrastructure (SDI) of Zurich, there are several comparable tasks that are processed by different offices. Currently, several datasets on the same topic are maintained separately and only merged in the spatial data infrastructure. One example of this is the unsealing of surfaces, which takes place either on public roads, in public recreational facilities or around public buildings. For each type of land, a different authority is responsible for the task of unsealing. Depending on the authority, different rules apply for data collection.

In the future, each topic for which several authorities collect data will be coordinated or managed by the cadastre organization and handled in a single database.

3. Once-only principle

Construction activity in the public sector is increasingly based on the building information modelling (BIM) methodology, which means that high-quality, structured data is already available for the construction phase. After construction is complete, the BIM model must match the actual reality and therefore may need to be updated based on surveying. Many constructions are included in the cadastre in a generalized form, which means that this data must also be updated. Until now, this data has been recorded twice, each time with a different target.

In the future, the cadastral system must ensure that the once-only principle is consistently adhered to. The BIM model is updated during the construction phase. The extract from the BIM data that is relevant for widespread use is then integrated into the cadastral data.

Trust and accessibility

All the principles described above serve to ensure the reliability of the cadastral data and, building on this, to bring other data topics up to the same high level of quality. Together with its partners, the cadastre organization ensures that all the information contained in the cadastre meets a clearly defined quality standard, is kept up to date and is easily accessible. Every authority can base its processes and directives on the cadastral data and rely on them. The cadastral data can thus serve as a legally binding basis for any governmental procedures.

Conclusion

Since its inception, the cadastre has already promoted several developments in the government. Today, many authoritative processes depend on reliable spatial data. In addition to specialized data, reference data is often also required. The cadastre must therefore develop from a multipurpose cadastre into a governmental digital twin. The already strong position of the cadastral system should therefore be used to raise the data quality standard in other areas that are processed on an interdisciplinary basis. Furthermore, data will mostly be recorded in the third and fourth dimensions in the future. The digital transformation of government tasks is being promoted and, with it, the role and importance of the cadastral system is being strengthened.

Further reading

DIN e.V. (2024). DIN SPEC 91607:2024-11, Digitale Zwillinge für Städte und Kommunen, Berlin.

EJPD (1987). Die Zukunft unseres Bodens. Ein Beitrag zur Verbesserung der Bodeninformation und Bodennutzung. Published by: Eidgenössisches Justiz- und Polizeidepartement, Eidgenössische Vermessungsdirektion, 1987

Steudler, Daniel et. al. (2014), CADASTRE 2014 and Beyond. FIG Publication No. 61. Copenhagen: International Federation of Surveyors (FIG), 2014.