Satellites have eyes that allow us to see and perceive a changing world, shaped by human activity and natural phenomena. They help us understand how to adapt and improve the way we live within it. That is how smart cities are born, "technological models that allow us to manage cities and thereby improve citizens’ lives," summarizes Benedetta Marsilio of e-Geos. In the fourth episode of Space Panorama, the experts of Italy’s leading Earth observation company describe how satellite geoinformation makes it possible to adopt strategies for prevention, maintenance, and better management of soil and territory—for both public and private entities.
The sensors observing us from above come in many different types. Optical ones can capture high-resolution images of the land for monitoring urban environments: "In the field of waste management, we can map and geolocate every bin and even their type—for example, plastic or paper," continues Marsilio, "to check whether all the necessary bins are in place and to optimize maintenance, such as the routes of collection trucks." They can also monitor a very frequent phenomenon: illegal dumping and accumulation. "With geolocation and a map that tells you exactly where the waste is, it’s possible to prevent it from becoming an open-air or illegal landfill."
Infrared for Green Spaces and Against Heat Islands
E-Geos has worked with the City of Rome to monitor the Castel Fusano pine forest and plays a key role in GeoRoma, with satellite radar and optical sensors as well as aerial surveys with ultra–high-resolution orthophotos. These tools help map green areas, identify zones of thermal anomalies and heat waves, and analyze critical weather events after they occur—or even support the management of major public events.
Thermal infrared sensors are among the most powerful tools for measuring the effects of rising temperatures in populated areas.
These are the so-called heat islands: "Temperature maps can be integrated with Istat population data," explains Marsilio, "so if an area has many elderly people and children, we can determine where more trees should be planted, or assess whether certain materials (building surfaces, roofs, pavements, etc.) are influencing high temperatures." In the hands of technicians and city managers, these tools translate into risk maps that show exactly where to intervene.
Radar Sense for the Ground
Radar sensors, such as those on board the Sentinels—the satellites of the Copernicus constellation—can "probe" the ground with microwaves and return, much like an ultrasound scan, the profile of the soil and everything that emerges from its surface. Interferometric precision is below the centimeter scale, allowing for the monitoring—hundreds of kilometers from above—of ground movements and the effects of large-scale construction in urban environments: "Take Rome’s Metro C, for example," notes Emanuele Mele, Head of Insar Service at e-Geos. "Multiple monitoring campaigns were carried out to detect ongoing deformations during construction, which made it possible to visualize ground subsidence and compaction in excavation areas beneath Rome’s urban fabric."
Interferometry is used not only to monitor cities but the entire national and European territory. The data processed by e-Geos form part of a vast mosaic compiled for the European Ground Motion Service, which tracks soil movements across the continent.
This is a valuable resource for territorial governance by institutions or private stakeholders seeking to safeguard their assets: "A municipality in a mountainous area might need to monitor landslide phenomena to see if they correspond to particular rainfall periods; forests or even volcanic areas can also be of interest. A large city may want to assess the stability of buildings and cultural heritage sites. For linear infrastructures such as bridges and roads, it’s essential to monitor how movement or deformation alters their balance and structural integrity, and to plan tailored maintenance to prevent further damage that could lead to failure or collapse. Private companies are equally interested in monitoring pipelines, gas pipelines, and other essential utilities that serve citizens," concludes Mele.