Dietmar Feichtinger’s latest project is a promenade five meters above sea level below the historic fortress of Bastia.

In the northern Corsican port city of Bastia, the Austrian-French architect Dietmar Feichtinger, together with the French firm Buzzo Spinelli, has now created a gently curving and technically sophisticated promenade right on the waterfront in contrast to the cliffs by the sea and the massive fortress.

The Austrian architect Dietmar Feichtinger, who lives in France, has made a name for himself with bridges, footbridges and crossings. His latest project, which opened at the end of December 2020, was also planned by the Styrian-born architect with his usual constructive simplicity and precision: a promenade five meters above sea level below the historic fortress of Bastia. The coastal path is called “Aldilonda”, which means “above the sea” in Corsican. “Floating between sea and sky” is how the architectural firm Dietmar Feichtinger Architetctes (DFA) itself describes the project.

The concrete promenade, which is around three meters wide, meanders in front of the rocks. The rusty red of the railing made of vertical posts in solid Corten steel harmonizes with the colour of the ferrous rock. It ensures safety and at the same time offers maximum transparency. The exposed nature of the entire path turns the walk into an experience, according to the office’s description: “The sea can be experienced through the area covered with a grating. The balcony is exposed to the surf; when the waves are high, the water penetrates the stainless steel grating on the rock and thus reduces the massive force of the water.”

The rock forms the massive natural foundation of the mighty enclosing wall of the Bastia fortress, which gave the city its name. Previously, the rocky coast below the fortress wall was only partially accessible. Now you can walk or jog between the surf and the rocks. Dietmar Feichtinger and Buzzo Spinelli realized the intervention after winning a competition in 2017, at a cost of 9.7 million euros.

Video of the construction of the 450-metre-long promenade

The promenade, which was anchored in the rock with 25-metre-long tension rods, follows the topography in a varied way. Dietmar Feichtinger and Buzzo Spinelli designed the path along various spatial experiences around the fortification walls. At one point, the five-kilometer path breaks through the bastion. Then again, the softly curving path – in contrast to the massive fortress – nestles against the rock, leans against it, widens out, offers places to linger and gives strollers direct access to the water.

The coastal path opens up the area between the citadel and the sea. And provides direct access to the fortress via an internal staircase. “Aldilonda” has also created a pedestrian link along the water between the port and the south of the city. Tourists can thus shorten their waiting time for the ferry.

At the point where the fortress wall protrudes furthest into the sea, the path at the southern tip pierces the rock with a tunnel. Daylight enters through a vertical light shaft. The side walls and ceiling are made of fair-faced concrete with wood grain. A staircase leads from here to the elevated viewing plateau of the fortress.

Dietmar Feichtinger once again realized the technically demanding project together with the Paris-based engineering firm schlaich bergermann partner (sbp France). Hydraulic tests in a basin in La Seyne sur Mer were necessary to determine the force of the wave impact – 14 tons per square metre. Anchoring the structure to the rock could only be achieved with acrobatic efforts by the workers, who hung from the platform of the fortress on a trapeze. The Lyon-based landscape architects IN SITU paysage et urbanisme were also involved as partners.

The multi-award-winning architect, who was born in Bruck/Mur and grew up in Graz, does not describe himself as a bridge specialist, but has built well over ten bridges in Europe. He became famous with the Passarelle Simone de Beauvoir over the Seine and his serpentine footbridge in the bay of Mont-Saint-Michel in the Wadden Sea of Normandy. The access structure has been open to pedestrians and shuttle services since 2014. The mountain and its bay have had UNESCO World Heritage status since 1979. Dietmar Feichtinger is currently working on a research project to reform the structure of the Paris conurbation at the Centre de recherche CEA Paris-Saclay.

Less promenade, more view: Atelier Bow-Wow from Tokyo are building half a bridge over the Isar in Munich. Read more here.

What happens when heatwaves turn cities into sweltering furnaces and concrete jungles become a real threat to health and quality of life? Urban cooling islands are the city’s underestimated lifesavers – but only those who map them precisely, understand them and use them wisely can really improve the urban climate. Time to shed light on the methodology behind the mapping, the artful interpretation and the practical application in a way that only true professionals do: with a pinch of tongue-in-cheek and a lot of technical depth.

• Definition and significance of urban cooling islands in the context of the urban climate
• Mapping methodology: data basis, technologies and challenges
• Interpretation of the results: From thermal patterns to urban climate strategies
• Practical application: Integration into planning, portfolio development and participation processes
• Relevance for climate adaptation, health and social justice
• Technical and planning limitations of urban cooling island maps
• Innovative examples from German-speaking countries and international benchmarks
• Governance, data ethics and the role of open platforms
• Strategies for perpetuation and scaling in urban planning
• Conclusion: Urban cooling islands as a key instrument for the resilient city of tomorrow

Urban cooling islands: Definition, meaning and urban climate context

The term “urban cooling island” is now on everyone’s lips – and for good reason. While the discussion about urban heat islands usually revolves around the problem of overheating, urban cooling islands stand for the opposite: they are those areas in the urban fabric that cool down noticeably even on hot summer days thanks to specific microclimatic conditions. They form cold air reservoirs, act as fresh air corridors or cool through evaporation and shade. In the age of climate change, in which heat waves are becoming more frequent and more intense, these zones are literally vital – for people, flora, fauna and urban infrastructure.

Urban cooling islands are not created by chance. They are the result of a complex interplay of vegetation structure, soil conditions, water surfaces, building density and surface materials. Parks, forests, meadows, cemeteries, watercourses and even certain backyards can become cooling islands if they are large enough and structurally diverse. Especially in densely populated neighborhoods, they act like oases – with measurable effects on the local microclimate and the quality of stay.

The importance of urban cooling islands goes far beyond subjective perception. Numerous studies, particularly from the DACH region, have proven their positive influence on reducing heat stress, lowering particulate pollution and improving night-time recreational temperatures. Vulnerable groups in particular – the elderly, children, people with pre-existing conditions – benefit from their proximity to such areas. Last but not least, urban cooling islands are a key element of urban climate resilience, i.e. the ability of a city to adapt to extreme weather conditions and minimize damage.

But how can these areas be identified and specifically protected, strengthened and developed in everyday urban planning? This is precisely where the mapping of urban cooling islands comes in. It is more than just a pretty map for the next sustainability report. It is an analytical tool that enables planners, landscape architects and municipal decision-makers to raise heat protection and climate adaptation to a new, data-based level.

In the planning discourse, cooling island mapping acts as a bridge between scientific analysis, political control and participatory urban development. It makes the otherwise invisible microclimatic processes visible and thus negotiable. The goal: a climate-resilient city that not only builds and designs, but also understands and protects. Those who ignore this risk not only tropical nights and overheated squares, but also a massive deficit in quality of life and social justice.

The urban cooling island is therefore not a niche topic, but a key indicator for sustainable urban development. It stands for the intelligent combination of ecology, technology and social responsibility – and for a city that remains liveable even at the height of summer. But for this to succeed, the methodology, interpretation and application of cooling island mapping must be right. This is exactly what we take a closer look at in the following sections.

Mapping methods: from satellite data to sensor technology – what really counts

Mapping urban cooling islands is a highly complex discipline that requires much more than just a firm grip on a thermometer. The basis of any serious analysis is a clever combination of remote sensing, in-situ measurements and urban climate modeling. Those who do it right rely on a coordinated set of methods that not only depict punctual extreme values, but also the entire spatial and temporal dynamics.

Satellite data is usually the first step. Modern remote sensing systems such as Landsat, Sentinel or MODIS provide high-resolution surface temperature data which – depending on cloud cover and overflight frequency – enable initial identification of hotspots and cool spots. Special algorithms are used to calculate vegetation indices (such as NDVI), land cover and temperature differences. But beware: the pure surface temperature says little about the actual thermal sensation on the ground. Those who rely solely on satellites are not mapping people.

This is why additional measurement campaigns are needed on the ground. Mobile sensors – attached to bicycles, cars or even drones – provide highly detailed temperature profiles along streets, parks and squares. Stationary climate stations record continuous values and allow daily and seasonal fluctuations to be analyzed. More recent developments rely on citizen science: equipped with simple measuring devices, city dwellers collect data on air temperature, humidity and wind speed, thus contributing to the consolidation of the database.

A real highlight are urban climate models that calculate small-scale temperature fields on the basis of geodata, building structures and simulations. Tools such as ENVI-met or the DWD’s Urban Climate Model offer the opportunity to run through various scenarios: How does the cooling effect of a park change if the vegetation is compacted or unsealed? What happens if a new development blocks fresh air flows? Such models provide decision-makers with a reliable basis for developing targeted measures.

But every methodology has its limitations. Remote sensing is weather-dependent and often too coarsely scaled. Ground sensors are expensive and usually only cover small areas. Models require precise input data and complex calibration. Therefore, the art of mapping cooling islands is the intelligent integration of all available data sources. This is the only way to create a truly reliable picture of urban cold air dynamics – and the only way to develop tailor-made measures.

Methodological diversity is both a blessing and a curse. It opens up enormous opportunities, but also requires a high level of expertise, coordination and technical infrastructure. Those who rely on quick fixes or one-source analyses risk misinterpretations and thus bad investments. The best cooling island mapping therefore always remains a joint effort by planners, IT experts, climate researchers and – last but not least – the people who experience the city on a daily basis.

Interpretation: Between data overload and planning relevance – how maps become knowledge for action

Any map is only as good as its interpretation. This is especially true when it comes to mapping urban cooling islands. This is because the seemingly objective temperature patterns only reveal their true meaning in the context of the urban structure, usage and social geography. Those who simply mark the coldest spots miss out on the real added value: the derivation of smart, effective and socially just measures for a climate-resilient city.

A central problem is scaling. Large parks appear on satellite images as impressive cooling islands, but small, well-connected green spaces are often decisive for the actual quality of life in the neighborhood. The interpretation must therefore always take into account accessibility, length of stay and intensity of use. Day and night dynamics are also crucial: some areas have a cooling effect during the day but store heat at night – and vice versa.

It becomes particularly exciting when the cooling island maps are linked with social and demographic data. Where do heat stress and social disadvantage overlap? Which age groups are particularly exposed? Where are there a lack of cooling islands near residential areas? Layers such as these turn cooling island mapping into a genuine management tool for socially equitable climate adaptation. They make it possible to set priorities, target funding and protect vulnerable groups.

But interpretation is also a balancing act. Too many layers make the map confusing, too few leave out important connections. This requires sensitivity, experience and a clear view of what is relevant to planning. The best maps are therefore often not the detailed works of art, but those that offer quick, understandable and action-oriented access – without neglecting the scientific foundation.

The communicative dimension should not be underestimated. Cooling island maps are powerful visualization tools – for politics, administration and citizens. They can fuel participation processes, defuse conflicts and create awareness. But they can also stir up fears or provoke misinterpretations if they are not explained correctly. Professional interpretation is therefore always a question of translation: from the raw temperature difference to the concrete option for action.

Ultimately, the quality of the interpretation determines whether the mapping of urban cooling islands becomes a paper tiger or a driving force for urban development. It requires not only technical know-how, but also a deep understanding of the complex interactions between climate, space and society. Only those who maintain an overview here can turn data into real actionable knowledge – and thus really cool the city of tomorrow.

Application in practice: From planning to policy – cooling islands as a building block of urban resilience

The art of mapping cooling islands only unfolds its full effect in practical application. This is where the wheat is separated from the chaff – and where it becomes clear just how much courage, innovative spirit and stamina there really is in the planning system. Urban cooling islands have long since become a central factor in urban planning. They are incorporated into climate adaptation concepts, shape development plans and set the tone for the development of green infrastructure.

Existing development is about protecting, networking and strengthening existing cooling islands. This can mean unsealing asphalt surfaces, targeted redensification with climate-active facades, planting shade-giving trees or creating new water areas. Cooling island mapping shows where there is a need for action – and where existing structures are already working optimally. Integration into urban planning competitions is particularly important, as it makes the difference between short-term show projects and long-term effective climate adaptation.

In new buildings, mapping opens up new horizons for climate-oriented urban design. It allows fresh air corridors to be kept clear, cooling zones to be planned in a targeted manner and green structures to be networked in such a way that entire districts benefit from the cooling effect. In cities such as Vienna or Zurich, the integration of cooling island maps into neighborhood development has long been standard practice – and the successes are measurable: lower heat stress, higher quality of stay, increased attractiveness for investors and residents.

Cooling island mapping also sets new standards in the area of participation. It makes it possible to involve citizens and make use of their experiences. Participatory maps, digital climate platforms and workshops with local stakeholders turn abstract temperature dynamics into a tangible topic. This promotes acceptance, identification and innovation – and increases the chance that measures will not only be planned but also implemented.

The political dimension should not be underestimated. Cooling island maps provide the arguments for funding applications, help to prioritize scarce budget funds and make the success of climate adaptation measures visible. They are the perfect tool to speed up the often laborious process of transformation in the city administration – and they send a clear signal to the public: this is not just talk, this is action.

But the application also has its pitfalls. Without clear governance, clean data and regular updates, cooling island mapping threatens to degenerate into a token exercise. Binding standards, open platforms and a culture of learning to deal with uncertainties are needed. Only in this way can urban cooling islands become real building blocks of urban resilience – and not forgotten layers in the urban data graveyard.

Looking ahead: governance, innovation and the future of urban cooling islands

The future of cooling island mapping is digital, connected and participatory – at least if you get it right. New technologies such as urban digital twins, AI-supported evaluations and open urban data platforms are opening up possibilities that were unthinkable just a few years ago. Real-time analyses, interactive maps and dynamic scenarios are turning rigid planning instruments into agile tools. However, this also increases responsibility: who decides how the data is used? Who controls the algorithms? And how does urban society stay on board?

Governance is the magic word. Successful cooling island mapping requires clear responsibilities, transparent processes and binding standards. Cities like Vienna and Zurich are showing how it’s done: with open data platforms, regular updates and consistent integration into all levels of urban development. In Germany, on the other hand, the principle of hope still often prevails – fragmented data, unclear responsibilities and a certain reluctance to innovate are holding back the enormous potential.

Innovative examples show that things can be done differently. In Vienna, for example, the results of cooling island mapping flow directly into the prioritization of greening projects, the management of heat protection measures and the development of new districts. In Zurich, they are combined with mobility data and social indicators to provide targeted protection for particularly vulnerable groups. And in Hamburg, experiments are being carried out with digital participation platforms on which citizens can report and evaluate their own cooling islands.

But innovation needs more than technology. It thrives on the willingness to admit mistakes, share experiences and learn together. The best cooling island maps are only as good as the network behind them – made up of planners, researchers, IT experts and committed local people. A new culture of sharing, open discourse and continuous improvement is needed. This is the only way that cooling island mapping can become a real driver for a resilient, liveable and fair city.

The future lies in scaling and perpetuation. Cooling island mapping must not remain a project for funding applications, but must become an integral part of every urban development strategy. This requires courage, resources and – above all – staying power. But the rewards are great: a city that remains cool, liveable and fair even in times of climate change. And despite all the digitalization, that is still the best news for the city of tomorrow.

In the end, the realization remains: urban cooling islands are far more than a planning trend. They are a touchstone for dealing with climate change, urbanization and social responsibility. Those who map, interpret and apply them wisely are not only shaping the city – they are also protecting its future.

Conclusion: Cooling island mapping as the key to a climate-resilient city

Mapping urban cooling islands is much more than a technical exercise. It is the essence of modern, climate-oriented urban planning. It combines data expertise with planning creativity, scientific precision with social responsibility and innovative technology with the courage to change. Those who precisely record, intelligently interpret and resolutely integrate urban cooling islands lay the foundations for a city that will remain liveable even in the hot summers of the future. The challenges are complex, the methods varied and the interpretation demanding. But the rewards are high: better quality of life, better health, more justice. Cooling island mapping is therefore not an end in itself, but the key to a truly resilient, sustainable city. And – despite all the love of data – it is also always a plea for a clever, creative and courageous approach to the most important asset we have: the urban climate.