In Switzerland, spatial planning is closely connected to the overall goal of preventing land take in order to protect agricultural land. Although municipal planning activities and building codes have been in existence in most cities since industrialisation and since medieval times in others (e.g. in Bern since 1405), and the first proposal for a national settlement law was made in 1920, the modern planning system in Switzerland stems from debates during and after World War II. In order to maintain the country’s capacity for food self-sufficiency during times of military besiegement and trading barriers, domestic agricultural land was to be protected by coordinating land use. The first supra-local plan (Plan Wahlen) was developed in 1939 to increase agricultural land from 180,000 ha to 350,000 ha as part of the war preparation (‘cultivation battle’). Thus, the first administrative department responsible for coordinating land use was the Federal War Office for Food within the Military Department chaired by Friedrich Traugott Wahlen, who subsequently became a Federal Councillor.

After the war, Switzerland underwent enormous economic development, which within a short time frame ‘overran’ the traditional, rural society (Gilgen 2012: 34) and gave rise to wealth and a modern, urban way of life. Technological progress, improvements in living standards, and rising individual aspirations led to major construction activities and changes in land use. Remote parts of the country were developed, while at the same time many people moved to the cities, which grew to an unprecedented extent. All of this resulted in an intensification of land use and the fraying of cities.

In order to steer developments in an orderly manner and thus counter the ‘housing cancer’ (Meili 1967, quoted in Koll-Schretzenmayr/Schilling 2008: 19), the distribution and use of land had to be regulated urgently. A debate arose about the necessary political-administrative steering and control mechanisms to counteract housing shortages, land speculation, and urban sprawl (Knoepfel et al. 2012: 418), including popular initiatives questioning the extent and limitation of private land ownership. Alarmed by the initiatives of the political left, bourgeois-liberal politics advocated to amend the constitution and insert a constitutionally protected guarantee of ownership – even though private property had been legally secured in the Swiss Civil Code since 1907 and in the Cantonal Constitutions since the 1840s.

The debate led to a ‘historic compromise’ (Knoepfel et al. 2012: 419) that was approved by the Swiss voters in 1969. The Federal Constitution was complemented by two new articles: spatial planning was established as a public field in Article 22^quarter (today Art. 75 SC), while private property was constitutionally protected in Article 22^ter (today Art. 26 SC). This solution represents the great importance of private property rights for the free democratic state while at the same time stating that land ownership is not an unlimited right but should also serve the public good. The use of land is therefore free within the framework of the legal system. In terms of sustainable spatial development, the public interest demands controlled settlement growth in order to strive for a compact, decentralised form of settlement.

To implement this new legal competence, planning laws were needed on the national level (to lay down planning principles) and on the cantonal level. Accordingly, the 1970s were noted for political debates on how to establish planning as a policy field. The first national planning law was approved by parliament in 1974. It included far-reaching instruments for local planning authorities to control land use (requirement of a building permit, zoning, and the separation principle) and to ensure plan implementation (e.g. added value capture, building obligation, expropriation). However, economic lobbyists called for a referendum. Swiss voters narrowly rejected the law in 1976 (48.9% in favour) and it did not come into force. In 1979, parliament passed a new version of the law that kept the fundamental principles but was softened in terms of the property-interfering instruments. This time, no referendum was called. The Federal Spatial Planning Act (SPA) came into force on 1 January 1980, laying down the principles of planning to the present day.

Apart from some minor amendments, the system and its legal basis remained unchanged until the early 2000s when the political pressure for reform increased. The debate was triggered by the Galmiz case that impressively demonstrated the weakness of planning to protect green space in the event of economic pressure to undermine it (Hengstermann/Gerber 2015). As a consequence, a popular initiative was launched by nature protection organisations to reinforce planning’s competences within the constitution. The Federal Council preempted this amendment by presenting a reinforced version of the SPA that was passed by parliament in 2012, approved by Swiss voters in 2013, and came into force in 2014. The revised law put a stronger focus on inward development, including stricter requirements for municipalities to zone, measures to promote the availability of land, and more precise minimum requirements to added value capturing.

Since 1969, spatial planning has been anchored in Article 75 of the Federal Constitution. The overall constitutional planning objectives are: (a) to ensure the appropriate and economic use of land, and (b) to ensure properly ordered settlements. The constitutional article determines that planning lies within the cantons’ field of competences. However, the Confederation lays down binding principles, and supports and coordinates cantonal efforts (framework legislation). The actual legal basis is embodied in the Federal Spatial Planning Act (SPA), 26 cantonal planning laws, and municipal building codes. Furthermore, the laws are accompanied by executive ordinances, such as the Federal Spatial Planning Ordinance (SPO) and its equivalents on cantonal level. The type and extent of admissible land use are regulated by the municipal building codes.

On a national level, planning is administered by the Federal Office for Spatial Development (ARE) as part of the Federal Department of the Environment, Transport, Energy and Communications (DETEC). The office is responsible for the legal supervision of planning conducted on cantonal level (in particular cantonal planning laws and structure plans), the development of principles, strategies and draft laws promoting sustainable spatial development, and coordinating settlement and transport aspects in urban centres and agglomerations. Furthermore, it coordinates the spatial impact of the government’s activities (Sectoral Concepts and Sectoral Plans) and serves as the coordination point for international cooperation. Recently, the responsible department (ARE) has been trying to coordinate national planning by developing a nationwide plan (Territorial Concept Switzerland) (see below).

On a cantonal level, similar offices exist. They prepare the cantonal planning activities (in particular the structure plan). Furthermore, they are responsible for the legal supervision of planning conducted on the municipal level. In some cases, they are responsible for zoning plans and building permissions as no further planning tier on municipal level exists (e.g. in urban cantons such as Basel-City and Geneva).

The administrative structure on the local level depends on the municipality’s size. As about half of Swiss municipalities have fewer than 1,000 inhabitants, the smaller ones typically do not have a specific planning department. They often apply generic building codes. Planning decisions are taken by a committee in an honorary capacity. The preparation of technical documents and administrative processes are outsourced to private planning offices. Larger municipalities and cities have building codes and run planning departments – which, however, very often take advantage of outsourcing planning administration to private offices, too.

In planning practice, the Zoning Plan is the most important planning instrument. In combination with the municipal building code, it contains all regulations for land use for an entire municipality. It is directly legally binding and forms the legal basis for the building permission. The zoning plan must comply with the superordinate structure plan of cantonal planning tiers. As a law-like document with direct effect, the zoning plan must undergo a public participation process and finally be approved by local voters in a mandatory referendum. It is usually valid for 15 years.

For specific projects of high relevance (e.g. shopping centre) or specific areas of high importance (e.g. village centre), a special land-use plan is needed. It contains more detailed regulations and has to be agreed on by the cantonal government and approved by the municipal parliament as well as local voters in a separate procedure.

Some cities combine these public law instruments with private law instruments. The cities of Basel and Biel/Bienne are known for their long-term land banking policy – owning a remarkable share of their own territory (20–35%); not selling any public land; and providing the land by long-term land leases only (Gerber et al. 2017). Other cities, such as Zurich, have intense cooperation agreements with cooperatives offering about 20% of the city’s housing stock.

In 2012, the Federal Office for Spatial Development (ARE) presented the first ever spatial plan for the entire country (the so-called Territorial Concept Switzerland). It contains a spatial vision for sustainable development and calls to improve collaboration across administrative borders and between 12 different action areas. The concept is driven by the idea of diversity and solidarity between the different regions and their contribution to maintaining the country’s international competitiveness. The country’s splendid scenery and the high quality of settlements are to be promoted by carefully treating the land as a scarce resource. The country’s spatial pattern is based on a polycentric net of small villages and larger cities. Different sectoral policies (such as transport, energy, and the environment) are to be coordinated.

Although developed by a federal institution, the Concept was signed by the 26 cantons as territorial visions fall within their legal competence. The document is not legally binding, but serves as an overall orientation framework in policy and across the planning actors, and is referred to in many planning reports.

Cantonal structure plans are considered the heart of Swiss planning as they coordinate planning activities from national to local level and across different spatially relevant sectoral policies (Schmid et al. 2021). They typically contain a spatial vision of how the canton shall develop over the next 15 to 30 years, how different (conflicting) activities are to be reconciled, and what the temporal priorities and instruments for actual implementation are.

The current structure plan of the canton of Aargau stems from 2011. Usually, it is updated every 10 years but to comply with the revised legal framework from the national law, the plan was revised and updated exceptionally in 2015.

The plan is composed of two parts:

• The cartographic part (called the ‘Spatial Concept’) describes the functions of the individual areas and municipality types, anchors the agglomeration policy and the rural area policy, and defines the main directions and strategies of the canton’s spatial development.
• The written part (called the ‘text’) contains six overall leitmotifs. They are translated into measures in 28 strategic priorities within six sectors of planning: settlement, landscape, mobility, energy, supply, and disposal. Each strategic priority results in between one and five measures.

As the Canton of Aargau is predominantly characterised by different spatial patterns, the measures taken differ. For the agglomeration of urban patterns along the central axis (being within commuting distance to Zurich), numerous measures aim to improve connectivity with public transport, densification measures, and decentralising economic development. In the more rural parts, the focus is on adapting to an ageing population and climate change. This results in condition-based measures (e.g. cantonal coordination of retail development) and performance-based measures (e.g. the objective that recreational green space shall be accessible within 15 minutes without a car from every dwelling) (Hartmann/Albrecht 2014).

The measures have three different levels of binding nature: Determinations are directly legally binding and are to be implemented in every planning activity by the public authorities. For measures relating to intermediate results, the final political decision has not been taken yet (e.g. voting is outstanding). However, public authorities have to consider these in their planning and must not do anything predetermined or make them impossible to achieve. Long-term planning will be listed as pre-orientation, which the public authorities have to consider as far as possible at earlier stages.

Roughly every 15 years, a municipality prepares its future spatial development. In 2018, the city of Thun started the process of revising its municipal zoning plan stemming from 2002. Prepared through 18 analytic reports on different sectoral policies and an overall masterplan, a first draft was presented to the public in 2019. Following numerous discussions with inhabitants, politicians and special interest representatives, a revised version was presented 1.5 years later. The new plan has to be verified by the cantonal planning authorities (compliance-verification only), passed by the municipal parliament, and approved by voters before it comes into force and regulates building activities for the next 15 years. As a municipal law, the municipal electorate is entitled to vote (local residents with Swiss citizenship, usually from the age of 18).

Thun is characterised as predominantly a residential town with decent economic facilities. Compared to other urban centres, density is low in Thun. The new plan aims to promote affordable housing and economic development without further outward new zonings – as new zoning would fail to comply with national and cantonal planning law. Instead, several areas in Thun will be upzoned, allowing the landowners a higher floor-area ratio on their property.