Several studies published in recent years show that the public sector is seeking to appropriate and master the technologies of digital twins. Whether it's the Miroir, Miroir report by the Caisse des Dépôts et Consignations, the joint call for proposals by the IGN, CEREMA and INRIA or projects launched by major consortia (Destination Earth by the European Commission, MINnD 2050, the UK's National Digital Twin Program), the digital twin is a worthy successor to geographic systems and databases in the history of computerisation, pushing back their limits even further.
Reinventing ourselves to understand complexity
The digital twin aims to go beyond any existing system by enabling government to be more responsive and anticipatory in its decision-making. What sets digital twins apart is their more comprehensive lifecycle and the fact that they update data natively by design. Often presented as a virtual replica of reality operating in a closed loop, the twin offers an unparalleled ability to pick up on weak signals and new trends in an area in a short cycle that traditional European Commission approaches would not have been able to detect. Climate change is blurring predictability and increasing the scale of natural hazards tenfold, as in the case of the catastrophic floods in the Valencia region (Spain) at the end of October 2024 or in Brisbane (Australia) in February 2022. Increasingly densely populated cities must adapt while accommodating users with competing needs. All these new challenges facing our regions are becoming increasingly complex to understand, forcing us to rethink our digital response.
First proof of value
The creation of a digital twin of the Gironde estuary is an excellent example of this way of reinventing our systems approach. The GIROS (for GIRonde OpenSource) project, carried out by Egis on behalf of the Grand Port Maritime de Bordeaux, shows how the installation of sensors on the river, coupled with several physico-chemical models of the natural environment, can be used to digitally reproduce the behaviour of the Garonne from Bordeaux to its mouth. In this way, a number of benefits can be achieved, both in the short term to optimise river dredging operations and in the long term to simulate the maritime accessibility of the Port of Bordeaux by 2050.
This exemplary experiment has been followed by several other equally remarkable initiatives. In particular, massive lidar data collection technologies have demonstrated their added value for the operation of urban motorways. Point clouds are regularly updated digital replicas at lower cost. They eliminate the need for operators and maintainers to make on-site inspections, which means on-call time and the risk of accidents. These point clouds can even be used for simulations. This is what Egis wanted to do at the end of 2022 for the Inner City Bypass urban motorway in Brisbane (Australia). Based on the point clouds used by its operators and with the help of Sensat, Egis implemented a flood simulator. Of course, the availability of such a tool before the spectacular floods a few months earlier would not have diminished the exceptional nature of this climatic disaster. However, the simulator would undoubtedly have helped to rethink certain operational procedures (road closures and diversions) in advance, taking into account the impact of the speed of the rising water on traffic. In addition, it would probably have made it easier to consider what equipment needed to be moved or protected as far upstream as possible, and where to set up evacuation areas for people, for example.
Simulated flooding of a tunnel on Brisbane's Inner City Bypass.
