We view and access the world around us with the help of an increasing fleet of satellites. Some of them take high-resolution pictures of Earth many times a day for civil and military use. Others expand the visible spectrum and measure the hyperspectral properties of the surface to monitor crops or find natural resources. These satellites offer a novel view of our planet that has already become natural and trivial to us. We use Google Maps to find addresses, investigate battlefield overviews on the daily news and watch the twirling lows approaching our location on the weather forecast thereafter. However, we rarely think about how these images came into existence, scrutinise their modes of vision nor their tremendous implications.
Satellites and their wide range of instruments are not just ordinary cameras we send to space to collect some photos, but rather, they allow us to adopt a perspective which is by all practical means hidden from us. Figuratively speaking, they separate the eye from the observer in order to expose what is distant and invisible because of its sheer magnitude. Just like the microscope, their instruments render ungraspable objects visible so they can be studied, dissected, and eventually manipulated. They are mostly unnoticed and can look down onto the earth like a falcon, survey every elevation, every building, every movement. To the eye in the sky, we like to believe, nothing is hidden, and therefore nothing is beyond our grasp, action and power. This privileged perspective fosters a mode of reasoning which uses their absolute objectivity to assert and establish political, military and sometimes also civil interests.
The Second Gulf War was justified with satellite imagery just as the involvement of Russian troops in Eastern Ukraine was investigated – with alternating conclusions – with the help of several civil and military satellites. Seeing is believing – this holds true at least as long as a nuanced interpretation is neglected. Especially when images that were obtained before and after a purported event are called on to construct causal chains to support a favourable narrative .
However, satellite images are only rarely scrutinised for their objectivity, at least not regarding the possibilities of tampering or relative blindness. This is, as I would argue, grounded in their unique perspective that focuses the sight of infinite eyes and offers a positionless view.
To understand the implications of these inconspicuous optical circumstances, a short view on the history of cartography – without which today’s satellite imagery would be unthinkable – may help.
One of the earlier examples of a satellite-like map in European cartography, Jacopo de’ Barberi’s “Veduta di Venezia” (1500, figure 2), offers a highly detailed view of Renaissance Venice. Its lavish embellishments typical for the period feature not only the Roman gods Neptune and Mercury but also the local winds which are depicted as detached heads shrouded by clouds and are placed in a way so that the viewer is situated beyond this heavenly layer, among even more celestial beings. The map lays the city bare to a divine observer, much like the all-seeing and therefore omniscient god of the Abrahamic religions, and simultaneously subjects its fate to his power, mercy and protection.
However intricate the enormous map is, it still fails to depict the parts of the city that are hidden behind a steeple or a tall building. While even god’s elucidating view illuminates most parts of the city, it still casts a shadow and thus both the allegorical and the quite earthly viewer are not that all-seeing after all.
Contemporary mapmakers were not bothered about this cartographic circumstance we understand as a fundamental imperfection of the bird’s eye view today. After all, the aerial perspective was advantageous over the centuries old practice of drawing objects in a map in relation to their importance or symbolical value rather than their dimensions and physical presence. However, the newly found interest in optics and surveying technology led de’ Barberi and his Renaissance contemporaries on a path to a more objective and realistic cartography. It was Leonardo da Vinci who produced a map only two years after the “Veduta di Venezia” that revolutionised a visual tradition. The Roman nobleman Cesare Borgia had seized the Italian city of Imola in 1499, however the foreign aggressor found it very difficult to reign and defend the city so he appealed to the polymath to draw him a map. At that point, da Vinci had already invested a lot of his time into the development of optical devices and perhaps took this commission as a challenge to find a better solution to the problem than those mapmakers used before.
He opposed the central perspective maps of de’ Barberi and countless others with a chart that registered all the buildings, streets and features of the terrain as if they were levelled and part of a ground plan . This ichnographic plan depicted the actual size and positional relations of its elements in a diagrammatical manner and avoided foreshortening and other perspectival distortions. Whereas older maps were angled at a more or less distinct viewing point, the ichnographic map surrendered perspectives of any kind as if one saw the scenery from infinitely many viewing points, or alternatively from an infinite distance. Precisely because it didn’t favour any particular view, precisely because it was a graph and an abstraction, it facilitated the orientation from an arbitrary point. But this neutrality regarding the viewer is only achieved by means of an equally rigorous control over its subject resulting in an anonymous, reserved and seemingly impartial depiction unlike its natural appearance.
The ichnographic plan requires and allows the confinement of space into the Cartesian grid, making it accessible to mathematical calculation and manipulation. It is an unrivalled device to plot points on a well-defined, perfectly level surface, and therefore to create and establish relations between them by simply drawing lines and, if needed, angles and more complex shapes. Furthermore, precisely because it isn’t a projection but an imprint of the city – the area, the country, the planet –, it deeply penetrates space, dramatically shortens it, and condenses it to a flat surface.
Because of this radical and geometrical elegant abstraction it is mutually agreed and thus universally used. However, ichnographic maps are not just formalised representations of terrain in the form of a mathematical model. They are commonly assumed to more or less intuitively provide an impression of the in situ situation, the ground truth. To read an ichnographic map is to imagine oneself being on the ground, seeing a distant place with one’s own eyes, while moving between locations at will, effortless and instantaneously.
It is therefore the cartographic instrument par excellence for all territorial actions and sovereign purposes that are associated with a need for maximal visibility. It allows the development, division, allotment and administration of areas as well as the planning of the movement of troops and goods, rendering it paramount to strategic surveillance and warfare.
From Renaissance mapmakers to Martian surveillance
Since the Renaissance, the ichnographic plan is at the core of most maps and had been adapted to suit a wide variety of applications and need. Surveyors and mapmakers match the most specific purpose with an even more specific map, endlessly creating bespoke models of a distant reality which already contains all the plans and actions soon to be carried out in the field. In this regard, ichnographic plans can be imperative as they reveal structure and relation of territory and human presence.
Following a long history of ichnographic maps and aerial photography, satellite imagery is just the latest addition to the instrumentarium of the cartographer, inheriting both their merits and pitfalls. This becomes evident when such images are the most trusted or even the only source of information. In Martian surveillance this is just the case.
The US-American and European space agencies NASA and ESA, respectively, conducted several missions to Mars to obtain detailed measurements of the planet’s surface and atmosphere. The Mars Reconnaissance Orbiter and the Mars Atmosphere and Volatile Evolution Mission (MAVEN, both NASA) constantly circle the planet, gather meteorological and geological data, and create aerial maps with a resolution as fine as 0.3m per pixel. Their instruments can not only take pictures of visible light, but also measure hyperspectral surface properties and ground elevation. Latest Mars explorations brought rovers to the ground, but the ultimate goal remains to deploy a manned mission to the surface of the red planet. Future landing sites are already explored and determined, however, there is still a rather limited understanding what the first astronauts will encounter there. The desire to know what they will see once they step out of their shuttle is an important incentive to create more cartographic material.
However, these satellite images are not confined to the space agencies’ laboratories and the scientific community. Many of them are also used to educate the public about Mars and current missions. The value of these unique and beautiful images for marketing and public relations cannot be underestimated since they almost always draw much attention, especially in Social Media. With such satellite images it is easy and inexpensive to remind the public about the importance of their research – a crucial effort to secure future public funding.