1858

Airborne Remote Sensing

Gaspard-Félix Tournachon (Nadar) (1820–1910)

The idea of creating a map of a large region—a city, a country, the world—required early mappers or cartographers to change their perspective, from an Earth-bound one to an imagined airborne or even extraterrestrial one high above the surface. Some early mappers succeeded more than others in moving themselves to this perspective; but, regardless, most early large-scale maps still suffered from a lack of geographic accuracy and/or scale.

That would all change with the advent of remote sensing—the ability to determine information about a place or object without needing to be physically in contact with it. Astronomy and spectroscopy of the Sun and other stars and planets through a telescope, for example, is a kind of remote sensing, as is charting a coastline from a ship using a spyglass or other surveying tools. For the mapping of the Earth, a major advance came with the development of airborne remote sensing, the ability to use information like photographs to make accurate maps of large areas.

The first examples of airborne remote sensing came from pioneering balloonists like the French photographer Gaspard-Félix Tournachon, who went by the pseudonym Nadar. In 1858, Nadar became the first person to obtain aerial photographs, from a balloon floating above Paris. While none of his earlier photographs has survived, numerous examples of airborne photos that he acquired in the decades after he perfected the process of shooting and developing photos in the challenging environment of a balloon basket attest to his skill. Nadar’s photos were used for city and government surveys as well as for tourist advertising.

Soon thereafter, kites began to be used to take aerial remote sensing photos, and eventually the first airplanes began to be used for aerial reconnaissance. During World War I, aerial photos could provide unique new information on enemy defenses and troop movements. After the war, commercial photographic remote-sensing companies in Europe and the US began providing mapping and surveying services from the air for government, industrial, and academic clients. Beginning in the 1960s, the inevitable start of remote sensing from space-based satellites would ultimately lead to today’s modern era of sophisticated spy satellites, as well as scientific satellites focused on imaging and studying our planet at ever-finer resolution and at ever-higher cadences.

A series of 1868 photographs of the Arc de Triomphe and Place de l’Étoile in Paris, obtained from the balloon “Le Géant” by the French photographer Nadar.