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Some cities want a “digital twin”

Loading playerSimCity is a famous video game series – the first chapter of which was released as early as 1989 – that allows you to simulate the growth and management of imaginary cities whose inhabitants pay taxes and have various needs, whose streets may have potholes or traffic problems and whose buildings first of all they need water and energy.

Digital twins, or digital twins, are meticulous and highly advanced replicas of objects, bodies, tools, machinery or industrial systems: they are used to virtually recreate a human body to understand which size of t-shirt is right for the real body of which it is a copy. or to analyze, test and improve entire production processes.

Digital twin cities – the digital twin cities, of which we have been talking for some years and of which there are already dozens of ambitious albeit still very partial applications – are, in essence, much larger and more complex versions of digital twins and, in appearance, something very similar to the cities of SimCity or the virtual and three-dimensional models of certain science fiction movies or series, in which instead of looking at a map, a model or a screen, someone observes futuristic and interactive three-dimensional representations.

– Read also: Video game cities are changing

Digital twins (when we talk about them in women we tend to take it for granted that we are talking about cities) are seen by those who believe in them, and obviously by those who propose software and systems for their creation, as a great opportunity to unite everything. a series of concepts and keywords of the technology of the last few years and obtaining near-perfect replicas of everything that happens in a city, or of what could happen to it if some aspect of it changed.

In the most optimistic – and for some utopian – expectations, the digital twins will be able to exploit artificial intelligences and the Internet of Things to receive, recreate and if necessary rework in real time information of all kinds on real cities of which they are a simulation, presenting all the information possible in a single three-dimensional context. “This new technology” wrote City Lab, a section of Bloomberg dedicated to present and future urbanism, “could change the way cities are designed”.

In reality, however, there is still a long way to go. Because cities are tangled and very complicated systems of things, and because the essential condition for a digital twin to really work is that the data that compose it are very many, very precise and up-to-date. On everything: from the weather to the traffic, from the air quality to the time at which lessons end in each school, from which areas are illuminated at any time to how much a certain sporting event congestes certain areas or influences, depending on the result, the movements of those who went to see it.

In theory, a properly built twin city should allow us to understand how, by changing the timing of certain traffic lights or making some changes to the road network, a busy road could be decongested; but also how and to what extent the construction of a new fifteen-storey building would change the turn of the wind or the beating of the sun on a certain neighborhood.

In practice, even more than the integration between the immensity of necessary data, the problem always remains the same: collecting them, through sensors and devices of all kinds, and trusting that they are all right. Without knowing how much water can enter, and enters, at a given moment in a manhole, and how much it is raining, it has rained and it could rain, it is difficult to know if and when the road in which that manhole is located will flood. Simulations are, at best, as good as the data they have, more they can't do.

It is the reason why, as City Lab noted, “many possible uses of the twin cities are for now only a hope”, not something concrete.

At the moment, moreover, there does not seem to be a single and main software, program or system to allow cities to make a digital twin. As City Lab wrote, Orlando, Florida is working on such a project with video game company Unity and aims to recreate its digital twin in a large circular room with a holographic image in the center. Similar projects, each at a different level of advancement and with different ambitions, are also in Phoenix, Las Vegas, Los Angeles and New York. But also in lesser known cities (for example Chattanooga, in Tennessee) or closer to Italy, such as Rotterdam, Helsinki, Rennes and Zurich. There is also, as told by a recent article on a site dedicated to geomatics, a project to digitally twin the whole of Germany.

The most ambitious, advanced and narrated project, however, is that of Singapore, a city-state of over five million inhabitants, who live on an area of ​​approximately 800 square kilometers. As City Lab wrote, the city has already created a model made from over 160,000 aerial images, to which it has combined billions of data that occupy more than 100 terabytes. Victor Khoo, who is in charge of it on behalf of the country's topographic agency, spoke of Singapore's digital replication as something that is already “smart, accurate, reliable and consistent”.

Already now the model, which can distinguish between streets and sidewalks, and which in different buildings distinguishes for example facades and windows, is used, Khoo said, to understand the impact on various levels of each hypothetical new building. For the future, the goal is to use it to reconstruct the causes of accidents, or even to exploit its mapping – which must be constantly updated so as not to become irrelevant – to hypothesize possible routes for self-driving cars.

For its digital twin, Singapore uses 3DEXPERIENCE, a platform of the French company Dassault Systèmes, which is listed on the stock exchange and deals with three-dimensional design and simulation: in short, it also does much more. The US Cityzenith, on the other hand, is much more concentrated on cities, offering city administrations the appropriate SmartWorldOS, its “urban operating system”.

In addition to the problems of obtaining and managing data – “we need adequate technological ecosystems,” said Khoo, “and to do it over time, in a sustainable way” – and the doubts about their practicality and convenience, digital twin cities also present problems of other type. Speaking of companies, for example, how fair or convenient is it for countries or cities to offer private companies the ability to handle all that data? Is there a possibility that, by having digital replicas, cities may become more vulnerable?

Among those who see possible integrations and partial overlaps between digital cities and the metaverse, and those who see in the digital twin cities only another unrealistic technological promise, there are also those who think that they could more realistically serve to manage single problems in single areas, or perhaps to create as realistic versions as possible of real cities, with the aim of showing or explaining to citizens the effects of certain choices. But even here – although the improvements have been tremendous since the 1989 SimCity – the road still seems to be long.

As Ray Gastil, director of the Remaking Cities Institute told City Lab: “the amount of data needed to recreate a realistic visualization, in which people can truly identify, is extraordinarily high”, and it should be at least at the level of that. – very expensive – obtained in the best movies and video games.

– Read also: The doubt of living in a simulation