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Mapping future cities, both above and below the ground

A Smart City must also be resilient. For one, the steady migration of population from villages to towns is putting pressure on civic services. This is also compounded by manic weather events due to Climate Change which are becoming the new norm. Put the two together and we have a situation like Mumbai, where thoughtless construction by greedy builders and unplanned shanty towns by migrants have blocking natural drainage. The result has been humongous flooding which neither favors the rich in their penthouses or the poor in their miserable shanties.

Resilience must ensure that cities plan ahead not just for five years, but for 10 or even 15 years, and take into account possible natural disasters while preventing the manmade ones. With a plethora of data sources in space, air and ground, and with tools like GIS and BIM, planning of cities has become that much more effective. Understanding the natural landscape and the demands on land by increasing population, the city planner can walk the tightrope of conservation and demand with relative ease.

However, a city is not just what exists above the ground. A well-planned city extends beneath the surface as much as it grows above. Many utilities and transport networks exist below the ground and this is not just today. There are interesting articles about Roman remains below London and abandoned subway lines below New York City. In fact, exploring below cities has become an adventure activity as much as speleology. While such adventurers may provide volunteered data about their explorations, it reinforces the fact that as our cities become smart, we need much more purpose collected data of the world below our feet to enable maintenance of existing assets and creation of new ones. Too often we face disruptions in water supply, sewerage, telephones and even Internet as digging for new utilities ignore the existence of older assets.

Mapping has to go below the surface and maps of underground assets have to be created and updated on a regular basis as much as the over ground assets. Looking for ‘what lies below’ is not new. In the early years of earth observation pioneered by ERTS, now Landsat, it was the geologists who were most appreciative of the new data source. The keyword was synopticity, the ability to look at large expanses of the earth which enables the big picture of lineament, folds and fractures so essential to understanding geology. Even so, what lay below could only be inferred but not seen.

With the advent of Synthetic Aperture Radar, one could see down to about a few meters provided the overburden was dry and the wavelength long enough. The L band radar on the Space Shuttle provided data of sub surface features in the Nile region of Egypt. Ground Penetrating Radar, a ground-based mobile device that can ‘see’ several meters below the ground, became available around the 1970s. It has become an invaluable tool to trace out features, particularly manmade objects like pipes and other artefacts when no or sparse records are available about such objects.

The need therefore is to map out the existing cities, both above and below the ground, before smartening them and to have a continuous process of updating the records as the cities grow. In a connected world as envisaged in a smart city, we cannot afford connectivity loss even for a moment because connectivity is the jugular of IoT and therefore of the Smart City.