Urban Tomographies. Martin H. Krieger

thing or notion) as we examine each image separately; we are filling in the details, figuring out, an imaginative draftsmanship. Tomography allows for, it presumes, such identity in manifolds, many images showing us a world or an object as we encounter it from different aspects.

      More generally, the project is to document a city in terms of multiple slices in space and in time and in type (hence tomography), a unity in that multiplicity of aspectival variations (a phenomenology), showing how people, machinery, and nature work together or coordinate to get the city’s work done (a choreography). Denis Diderot (circa 1760), Charles Marville (circa 1860), and Eugène Atget (circa 1915) once did much the same for Paris, in systematic surveys and multiples. Ordinary everyday life, in its tissue of negligible detail, is rich and deep, and through tomography we discover that detail in the context of an encompassing understanding of the whole.⁷

      The cinematic arts and opera are suggestive models. The cinematic arts are concerned with multiple slices and cuts, compositing, storytelling, and screen language.⁸ In opera, the claim is that music, sound, and visual action form an indissoluble whole. In both cases there is also the claim that repeated viewings or performances are rewarding, your noticing and appreciating new things each time around as well as recalling what you have already taken in, perhaps radically revising your understanding of the work. Both also allow for multiple scenes on the same screen or proscenium, each playing against the other.⁹

       Slicing Up a City

      A tomograph is a knifelike device meant to section or cut thin slices of tissue. Computer-aided tomography uses thin, almost one-dimensional X-ray images, or “pencils,” of an object to construct a two-dimensional image of that slice of an object, and presumably those slices can then be fitted together to get a three-dimensional model.

      We slice up a city or a type of phenomenon or a process through multiple aspects: photographs of the facades of many storefront churches allow us to appreciate urban religiosity as a diversely manifested phenomenon; photographs of the merchandise displays in ethnic markets show the variety and the similarities of urban subgroups; and photographs or videos of the various aspects of the casting operation in a foundry (Figure 6), forming an album, provide what we need to imagine the whole process.

      Most urban situations are complex and varied and have many temporal aspects. To document a street market we need images from various perspectives but also of different sorts of transactions, of the insides of the booths, at various times of the day or week, and so forth. In addition it would help to interview the participants to discover their accounts of what is going on—in effect, additional slices or aspects.

      We might capture such a situation or phenomenon one at a time, using still photography or audio recording. But now there are inexpensive sensors available and sufficiently ubiquitous to document urban life more pervasively, to provide a very large number of slices or aspects—unlike our experience in 1963 that resulted in just one movie of President Kennedy being assassinated. Namely, video-equipped cell phones are such sensors, and they are carried about all the time. We might imagine a swarm of such users (that is, crowd sourcing) documenting an event or situation, each from his or her own perspective or interest (Figure 5).¹⁰

      Such a corpus of images, videos, and sound clips, less as a set of disjointed pieces of a puzzle and more as a series of differently detailed renditions with the documents labeled and organized by location and time and perspective, allow us to better know the whole that is here presented aspectivally.¹¹ Ideally, we have lived in this place or we have already done fieldwork ourselves, so we have some idea of what that urban world is like. We start out with a sense of what there is in a city and can fill in and modify our initial notions, check them out, and learn more. Urban tomography leads to a fuller sense of place and activity.

      The actual city is an archive of repeated forms and structures and designs allowed to age, repair, and renew themselves. The ubiquity and variety of these forms in a city are products of the political economy of real estate development and decay, the rise and relative decline of neighborhoods under the influence of larger societal forces, and a politics of public choice for support and subsidy.

      So the city itself is an archive of its past, much as a population is an archive of its past (as the evolutionary biologist would say). However built and for whatever reason, much of the built environment lasts well beyond its planned lifetime, perhaps rebuilt and repurposed. Speculative building of a large number of similar structures, whether they be stores or homes or industrial buildings or office buildings or factories, means that many structures have many identical representatives. In time each particular building is altered to suit its current or prospective owners; some buildings are destroyed, others restored. (The usual example is a planned urban development, as in a Levittown, fifty years after opening.) New uses make what once appeared to be doomed neighborhoods or building types into lively, productive, and economically viable places and enterprises. A real estate market that allows for these processes will eventually produce a city that has a wide variety of what were once similar buildings and uses, likely to be spread throughout the city although not in all areas. What was once repetitive and the same becomes variegated and diverse. Development alters the consequences of genetic endowments. Moreover, new uses tend to be agglomerated in certain areas, there being good reasons to have competing enterprises located near each other. Yet those enterprises also specialize, providing for a wide range of niches. So might the story of urban economies be told. The storefront houses of worship we see when we drive around town are products of just those processes that have built and rebuilt cities, especially since industrialization.

      What an archive provides, what a built city provides, is a range of possibilities and instances, which then become inhabited in ways we do not foresee. The artist Frank Stella made a series of works (sculptures, paintings, prints), one or more for each chapter of Moby-Dick (which has 136 chapters).¹² Even knowing Moby-Dick well and Stella’s previous works, it would be difficult to predict how each chapter would be instantiated and the range of the instances. However, Moby-Dick provides Stella with the chance to make works that form a series, an archive, a meaningful whole, each work, however, on its own. So the city too provides for its inhabitants places and spaces to make their lives meaningful and whole.

       Choreographies of Repetition

      So we might have an account of industrialization, but now that of the Second Industrial Revolution and the great migrations that have continually populated the City of Los Angeles: the interrelated choreographies of where and how people worshipped and worked, and the engineering—industrial, civil, chemical, and electrical—and the coordinated networks and systems and infrastructures that supported industry and residents and that allowed them to live close by each other.

      The Second Industrial Revolution made possible photography, radiology, and the images we can make, and the images reflect possibilities built into the technologies of cameras, lenses, films, and X-ray machines, now an ongoing transformation from the analog film to the digital sensor domains, from colloid chemistry to digital electronics. What was once a black art of emulsion manufacture is now another black art, the design of algorithms for processing sensor data or pixel information in the digital file. Much the same has taken place in the world of aural recording and reproduction, albeit microphones (and lenses too) are not digital devices.

      The studies I discuss here are, in effect, a repetition of a past history, now in Los Angeles rather than Paris. As for Paris, I am thinking of Denis Diderot’s (1713–84) description and engravings (Figure 7) of workers in the arts et métiers for the L’Encyclopédie (1751–60ff), Charles Marville’s (1816–79) photographs (1858–77) of the streetscapes of Paris before and then after Haussmann eviscerated them under Napoleon III’s direction (Figure 4), and Eugène Atget’s (1857–1927) systematic photographing of Paris’s streets, stores, monuments, residential interiors, parks, and workers in the early part of the