Scanning Theory:
Observations of a Traveling Photogrammeter

June 10th: Seeing the Water

On a windswept beach in Southern Oregon, the intertidal zone is scattered with jutting, water-fractured boulders. Shot through with veins of quartz and sheared at dramatic angles, the rocks seem thrust from the earth, piercing the dark sand. Quietly and methodically, I pace circles around one such outcrop, spiraling closer and closer, never breaking contact. This is not some ritualistic dance but a process of recording and remembering. I leave the beach and within an hour a virtual twin boulder appears on my phone—a high-resolution, photo-textured 3D replica of the real thing. Miles down the road I re-encounter the object’s replicated surface, examining the digital double in ways I never could a photo: spinning  it around as if I held it in my hands, then zooming down to examine the intricate, weather-drawn details of its rocky surface. I download the model and save it to an online gallery, preserving it alongside other photoscans: a virtual cabinet of curiosities recording snippets of my travels.  In June 2023 I visited the United States from Australia and gathered a trail of such digital doubles, experimenting with 3D photogrammetry as a medium for recording and interpreting place. In planning my cross-country trip I was guided by memories of architect, geographer and cultural landscape scholar Paul Groth, who spent a lifetime teaching and practicing the careful observation and analysis of ‘ordinary’ American environments. In lectures he would gently rail against his culture’s blindness to the stories embedded in everyday place, observing that “Americans are like fish who can’t see water.” My aim, while driving across the country from west to east, was to read the landscape with an open and curious mind, taking every lesson I could from the complex text I was immersed in. Throughout the trip I found myself drawn to 3D photogrammetry: it consistently provided new perspectives on ordinary objects, drawing my eye to settle in spots I might otherwise have passed over—helping me to see the water. Why was this? What makes a photoscan different from a photograph, and what new ways-of-seeing does it open up for the careful observer of everyday place? 

In considering photogrammetry as a technology distinct from photography, we must delve a little into its origins and development. Modern photogrammetry is concerned with the creation of the photoscan—a 3D representation of an object stitched together from 2D images. A crucial underlying algorithm is Structure from Motion (SfM), developed in the 1970s: Like the human brain constructs depth perception from the two flat perspectives of our eyes, SfM algorithms construct three-dimensional point clouds by the serial analysis of multiple images. These point clouds can be rebuilt as the triangulated surface of a 3D model, with the source photos re-projected as textures to create a realistic virtual representation of a scanned object. Crucially, the applications of photogrammetry have grown since the 1970s with its increasing ease of use. Early academic applications were adapted for widespread use in movie visual effects during the late 1990s. More recently, photoscans have become crucial to video game development, where real-world 3D objects are digitally duplicated, repackaged and sold as virtual assets—it is much faster to capture and launder the complexity of real-world objects into virtual space than to model that complexity from scratch. Today, all-in-one cloud-based photogrammetry apps are freely available and easy to use, broadening the potential ranks of traveling photogrammeters: anyone with steady hands and a smartphone can capture a photoscan in minutes, with no special knowledge or expertise. Given this growing ubiquity, there is a pressing need for a theory of photogrammetry. Photography is a well understood and deeply theorized medium, both for tourists and professional spatial practitioners, but 3D photogrammetry has little such theoretical scaffolding—until recently it was a niche domain requiring specialized knowledge and equipment, and most of the academic literature still focuses on practical applications in preservation, archaeology, and related disciplines. Through the lens of three photoscans captured in June 2023, this essay considers photogrammetry as a medium distinct from photography, and suggests two theoretical frameworks for understanding their difference. Walker Percy’s idea of the preformed complex and Umberto Eco’s theory of the open work are introduced as pathways toward a theory of how accessible, high quality photogrammetry might change the way we see and understand the everyday landscape.

June 17th: The Garden of Eden and the Preformed Complex

Outside the town of Moab in eastern Utah, a hundred-odd cars idle in the mid-June sun. The well-paved road off US Highway 191 carries a million and a half visitors each year past the toll booth and into Arches National Park. Arches is an archetypal example of the 20th century American national park—a well-choreographed confluence of natural beauty and civil engineering designed to enable mass-scale encounter with the sublime. Comfortable roads penetrate the landscape, guiding visitors along a plateau of towering red rock buttes, eroded sandstone canyons, and the park’s eponymous weather-sculpted arches. Park literature welcomes the “Auto Touring” visitor, who can cruise past dozens of attractions with names running the gamut between evocative biblical metaphor (Tower of Babel, Fiery Furnace) and more straightforward description (Double Arch, The Phallus). In the parking lot at The Garden of Eden, I wander away from a cluster of fellow visitors and walk into the sandstone landscape. In a few minutes I am beyond earshot of the carpark, in a small desert wash dotted with low-lying brush and surrounded by towering ochre pillars. My eye catches on a gnarled and sun-bleached juniper branch, and I pull out my phone to start a new photoscan. 

Seventy-odd years earlier and several hundred miles down the Colorado River, novelist and philosopher Walker Percy addressed the nexus of national parks, photography and mass tourism in his 1958 essay The Loss of the Creature. Taking the example of the Grand Canyon, Percy suggests that most visitors never truly encounter the wonder of this landscape on its own terms. Instead, their experience of the Grand Canyon is mediated by what Percy terms the preformed complex—the shared cultural image of the Grand Canyon implanted in their minds long before they arrive. Percy writes that “the sightseer measures his satisfaction by the degree to which the canyon conforms to the preformed complex. If it does so, if it looks just like the postcard, he is pleased; he might even say, ‘Why it is every bit as beautiful as a picture postcard!’” Further, Percy suggests that the sightseer’s instinct to capture a photo of their own further distances them from direct encounter: “At the end of forty years of preformulation and with the Grand Canyon yawning at his feet, what does he do? He waives his right of seeing and knowing and records symbols for the next forty years.” Prefiguring Marshall McLuhan’s famous observation that “the medium is the message,” Percy argues that the traveler’s way-of-seeing has become distorted and, ultimately, imprisoned by the camera. The subsequent decades have only underscored his insight that photographic mental regimes dramatically mediate our perspective on the world. The familiar lament that we are glued to our phones only part-way captures the situation: we can look away from the screen, but the smartphone’s way-of-seeing stays with us. Metaphorically, we are all afflicted with photographer mindset, walking around with a camera lodged in our brain, its lens interposed between us and the world

In Arches National Park the road chaperones lens-bound traveling photographers through a curated sequence of viewpoints, designed to ensure their experience coincides with the park’s preformed complex. The photographer is directed towards vast panoramas and scenic viewpoints, but these are of less interest to the photogrammeter, who is viewing the landscape through a different technological lens. This is not to suggest that the photogrammeter comes closer to Percy’s ideal state of direct encounter with place. Instead, the photogrammeter has an opportunity to circumvent the preformed complex because their technological lens points them in a different direction: to capture a good photoscan, the photogrammeter must orbit around their subject, capturing it from all angles. The photogrammeter seeks objects, not perspectives, and in doing so has a chance to see the landscape differently than the traveling photographer.

In the Garden of Eden, a dead juniper branch has come to rest in the desert wash where I stand. About three feet long, it touches the earth in four places—its bounding, craggy topology echoing the rocks around it. My photoscan captures its tone: sun-bleached on one side and dust-stained on the other. Coarse pebbles have collected in a hollow underneath, evidence of the torrential rains that sometimes scour this landscape, and which probably dislodged the gnarled timber and brought it to rest here. The photogrammeter’s lens has directed my attention away from the preformed complex of panoramic viewpoints and towards a smaller, quieter, more granular appreciation of the forces and processes that created both this branch and the towering sandstone stacks around it. The traveling photogrammeter has, at least for a moment, displaced the preformed complex and encounters the landscape anew.

June 23rd: The Parking Meter and the Open Work

Founded in 1825 at the summit of the Ohio & Erie Canal, the history of Akron, Ohio parallels that of American transport infrastructure. The construction of large water-powered mills here made the city a key center for processing and transshipment of grain. When the canal’s shipping function was superseded by rail and then road transport, Akron’s identity was transformed—water from canals was turned to industrial use in rubber vulcanization, and the city began to promote itself as “The Rubber Capital of the World,” a key cog in the Midwestern industrial network that motorized America. 

Arriving in downtown Akron in late June, I turn off Mill Street and park behind the old Quaker Oats factory, which parallels the railway and lies within a quarter-mile of the Innerbelt highway and the old Ohio & Erie. The mill operated here from 1884 to 1970 before being converted to a retail and entertainment complex, with the site’s towering silos repurposed as hotel rooms. Today the building is mostly unused and the small parking lot is empty on a Monday afternoon. Stepping out of my rental car, my eyes settle on a row of yellow painted double-head parking meters lining the curb. I scrounge for quarters in my center console, feed the meter, and pull out my phone to capture a photoscan. 

Months later, while reviewing the scan, I tumble into the complex history of this object. Zooming into the front face I spot a small blue plaque identifying this as a ‘Model N’ parking meter from POM Incorporated of Russellville, Arkansas. POM, formerly known as Park-O-Meter, traces its history to the invention of the parking meter in 1935, and has been manufacturing in Russellville since 1964. If Akron, Ohio was the Rubber Capital of the World and Toledo was the Glass Capital, perhaps Russellville was the Parking Meter Capital: a site of the kind of industrial specialization that was common in 20th century American manufacturing. But the history of an object cannot be reduced to its model number or place of origin. This parking meter is a specific object in a specific place with a specific history. The bright yellow paint on its surface is scratched and pitted, sometimes exposing the raw metal beneath. The meter attendant’s key has worn away a circle around the coin vault keyhole, and on the right hand side of the machine the quarter slot is rubbed to a shine by unknown thousands of coins. The photoscan captures the passage of time: the marks, knicks and wear patterns that identify it as unique and emplaced, a commodity object transformed by its environment. This is the beauty of studying the everyday landscape—history at all scales is embedded in the world around us, waiting to be uncovered if we take the time to look closely.

How does a photoscan compare to a photograph as a tool for closely reading an object’s embedded history? Without doubt the two technologies are complementary, but it is worth considering the particular value of the emerging, less well-understood medium. A useful theoretical perspective is Umberto Eco’s concept of an open work. Writing about visual art in the 1960s, Eco distinguished between art whose meaning is intentionally singular and fixed by the artist, setting it against the open work that deliberately invites a multiplicity of interpretations. Eco refers to a “field of open possibilities” in which “the viewer can (indeed, must) choose his own points of view, his own connections, his own directions… .” The photograph and the photoscan, when set against each other, show this distinction in a very literal way: the photographer looks through their lens and chooses a single perspective to represent the object on the other side. In contrast, the photogrammeter records a field of images, a 3D cloud of information that is re-assembled into a more detailed and complex record of the object than any single photo can contain. 

The complexity of a photoscan when compared to a photograph is intrinsic to the medium: a photoscan is always three-dimensional, always interactive and always multi-scalar. While a single photo certainly can be semiotically open, the viewer’s agency is always constrained by the photographer’s choice of scale, perspective and framing. By contrast, in re-encountering a photoscan we are presented with a 3D object that requires interaction and hence requires us to take agency in its interpretation. The object can be rotated, enlarged, turned over, and examined from any number of perspectives. The viewer has agency over the artwork, which invites them to look closely and draw out new meanings from it—including meanings never considered by the photogrammeter at the time of capture. The traveling photogrammeter captures a complex and intrinsically open record of an object, and this multiplicity allows the viewer to interpret and recontextualise the underlying object more readily than the viewer of a photo.

The oceanside boulder in Oregon, the juniper branch in Utah, and the parking meter in Ohio all point towards the potential of photogrammetry as a medium for seeing, recording, and understanding place differently. My experience looking through the photogrammeter’s lens gave me space to step aside from the preformed complex, viewing my surroundings with fresher eyes. After the fact, the intrinsic complexity of the photoscans I collected gave me a more nuanced understanding of these objects than would be possible from a single photograph. The technological frontier of photogrammetry continues to advance, and we might expect to see its use expand in the near future. It is not, of course, a universally applicable medium: photogrammetry works best on singular objects, and often misses context that a photograph might capture. For now, a photoscan also cannot capture sound, action, and atmosphere like video can. Nonetheless, for the thoughtful observer of cultural landscapes, photogrammetry can be a powerful tool with particular potential for architects, geographers, and other spatial practitioners. An architect’s eye, freed from the photograph’s fixed perspective, can better interrogate the complexity and nuance captured in a photoscan. A geographer can assemble in minutes a multi-scalar and inherently spatial record of place that can be revisited and interrogated much more readily than a single photo. Our disciplines call on us to engage with place deeply and seriously. Photogrammetry can help displace us from ingrained habits of seeing and thinking, prompting us to understand our surroundings anew. With the right tools and the right frame of mind, we can strive to re-encounter place with an open mind and, if it catches the light just right, to see the water we all swim in.

References

1. Paul Groth, “Frameworks for Cultural Landscape Study” in Understanding Ordinary Landscapes, eds. Paul Groth and Todd Bressi (New Haven: Yale University Press, 1997), 15.
2. Shimon Ullman, “The Interpretation of Structure from Motion,” Proceedings of the Royal Society of London 203: 405–426.
3. Ian Failes, “Mission: Impossible II - a virtual production game-changer”, published May 27, 2020, https://beforesandafters.com/2020/05/27/mission-impossible-ii-a-virtual-production-game-changer/.
4. The Astronauts, “The Secrets of Witchfire Graphics: The Photogrammetry”, published November 29, 2023, https://www.theastronauts.com/2023/11/secrets-of-witchfire-graphics-photogrammetry/.
5. Stuart Granshaw, “Editorial: Imaging Technology 1430–2015: Old Masters to Mass Photogrammetry,” The Photogrammetric Record, 30: 255-260.
6. John Urry and Jonas Larsen, The Tourist Gaze 3.0 (London:Sage).
7. Tim Davis, “Photography and Landscape Studies,” Landscape Journal 8, no. 1 (1989): 1–12.
8. Carmen Marín-Buzón, Antonio Pérez-Romero, José Luis López-Castro, Imed Ben Jerbania, and Francisco Manzano-Agugliaro. "Photogrammetry as a New Scientific Tool in Archaeology: Worldwide Research Trends" Sustainability 13, no. 9: 5319.
9. “Arches NP Park Reports,” National Parks Service, https://irma.nps.gov/Stats/Reports/Park/ARCH.
10. “Auto Touring,” National Parks Service, https://www.nps.gov/arch/planyourvisit/driving.htm.
11. Walker Percy, “Loss of the Creature,” Forum 2 (Fall 1958): 7.
12. Percy, “Loss of Creature,” 7.
13. Marshall McLuhan, “The Medium is the Message,” Forum 3 (Summer 1960): 19-24.
14. Paige Cirtwill, “After Industry: Akron, the Rubber Capital of the World,” Midstory, October 20, 2021, https://www.midstory.org/after-industry-akron-the-rubber-capital-of-the-world/.
15. “After Industry.”
16. Ohio History Connection, “Quaker Oats Company Plant,” last modified November 20 2012, https://www.ohiomemory.org/digital/collection/p267401coll34/id/7857.
17. Adam Miller, “Park-O-Meter,” Encyclopedia of Arkansas, last modified June 16 2023, https://encyclopediaofarkansas.net/entries/park-o-meter-3116/.
18. David Price and Zhu Wang, "Explaining an Industry Cluster: The Case of US Car Makers From 1895-1969,” Economic Brief, no. 12-10 (2012).
19. Umberto Eco, The Open Work, trans. Anna Cancogni (Cambridge: Harvard University Press, 1989), 86.
20. Lucia Díaz Vilariño, H. Tran, Ernesto Frías Nores, Jesús Balado Frías, and Kourosh Khoshelham, "3D mapping of indoor and outdoor environments using Apple smart devices," ISPRS-International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences, (2022).

Note: Scanning Theory was first publish in Pidgin 32 by Princeton School of Architecture (2024)