Las nuevas tecnologías se abren paso con fuerza a la hora de documentar yacimientos arqueológicos o ponerlos en valor, pero también pueden servir para proporcionar puntos de vista o enfoques de análisis que hasta ahora no resultaban posibles. La técnica de la fotogrametría ha permitido a Philip Sapirstein, profesor de arte de la Universidad de Nebraska-Lincoln, profundizar en el conocimiento del diseño original y las fases de construcción del Heraion de Olimpia. Desde Mediterráneo Antiguo nos hemos querido acercar a este trabajo, de gran interés por su enfoque, así como también a otro de los proyectos que dirige, el Digital Archaic Heraion Project at Mon Repos. (Entrevista en inglés).

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Overview 3D perspectiva. Photo: Philip Sapirstein

Question – The data you have obtained have already led to new observations about the Olympia temple and challenge the prevailing understanding of its design and phasing. Could you explain what are your main conclusions?

Answer – The main conclusion to date is that the Hera temple was originally constructed with the stone colonnade. Since the late 19th century, when it was first excavated and studied, it has been assumed that the temple began with wooden peristyle columns, and that these were gradually replaced by stone ones. Dating about 600 BC, the Heraion would be the first surviving large temple in the Doric style, and the wooden columns have been interpreted as showing that the Doric style developed much earlier than can be shown directly by the surviving evidence—because earlier Doric temples would have been constructed in wood and thus not survived.

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Details from Hera temple. Photo: Philip Sapirstein

I’ve been able to show instead that the temple almost certainly had stone columns from the beginning, and thus the Heraion is more of a break with previous architectural traditions and a new direction. That’s an exciting result for me because there are many scholars nowadays who have been questioning the big story about how Greek architecture developed during the Archaic Period, and now I can show the major temple at Olympia in fact supports the new ideas that Doric architecture was synthesized rather quickly in the decades around 600 B.C. I go over the evidence in detail and come to these conclusions in an article that will be published in the next issue of the American Journal of Archaeology (October).

There are some other results too. Since I am working on preparing these with my colleague, David Scahill (at the ASCSA), and we don’t have manuscripts under review, I’ll be brief. One result we are working on interpreting is that the building has a pronounced slope throughout, and we believe this may have been an intentional features, perhaps a precursor to the curvature observed in the platforms of later Greek temples. Other research has to do with the stone colonnades—since if they are original to the building (and not replacements for lost wooden columns) they must be carefully restored and reassessed as examples of stone architecture from the beginning of the Doric style. Finally, we’ll work on restoring the (now missing) superstructure of the temple. I am calling this project the Digital Architecture Project for convenience—any work on Olympia or other related sites using photogrammetric recording are called the DAP.

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Overview South-west. Photo: Philip Sapirstein

Question – Photogrammetry is a complex documentation technique, how it has helped to suggest a new date to the Heraion?
Answer – I haven’t argued for a new date to the Heraion, which was begun around 600 B.C. according to the stratigraphic evidence. The elimination of an early phase of wooden architecture does change our dates for the stone colonnades, by moving them to the beginning of the construction, and I’ve also worked out when repairs were made to the building during the 1000 years it was in use.

As far as photogrammetry, it has been tremendously valuable for acquiring all the documentation I need for studying the building. While it is essential for me to look at the ruins in person, whenever I am working on a paper—like this forthcoming AJA study—I need to go back and check the remains dozens of times as new questions come up. As a professor in the USA, I can only go to Olympia so many times during the year, and so having very reliable and very high quality 3D imagery of the site means I can virtually explore the remains whenever I need to, wherever I happen to be located. The imagery also can be displayed in a way that is much more convenient to work with than on site. I mean, I can produce plans showing the whole temple from above at very high (1mm) resolution—so I can quickly compare one part of the building to another, take measurements, etc., in a way that would be very hard to do in person on the site. I can produce elevation views too, and cross-sections, very quickly, so I can cross-check information in the 3D models much more efficiently than I can do on this complex site. The Heraion is about 20 x 50 m, with columns standing 2.5-5.5 m above the ground, so it is not easy to navigate the site in person and get the kinds of measurements and spatial relationships I need.

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Field work at the Hera temple. Photo: Philip Sapirstein

Another example is an article coming out soon in the Journal on Computing in Cultural Heritage, which describes work I did with a computer engineer, Eric Psota (UNL), to develop a computer algorithm that automatically restores columns drums. There are about 100 fragments of drums and capitals that fell from the Heraion and are nowadays stored in blockfields nearby the temple site. I was able to use this code to reconstruct about 80% of these pieces and restore them to their original positions (virtually) in the 3D model of the colonnades. So, I now have several complete columns in areas of the colonnade which are missing, and I’ve augmented several others. This lays essential groundwork for future study of the history of the colonnades.

Question – You are leading the Digital Architecture Project (DAP). Could you talk us briefly about it?
Answer – The DAP is the designation for any digital / photogrammetric recording work on early Doric monuments, like the Heraion at Olympia. So far, it includes previous digital work at Corfu, and we’ve also examined the Apollo temple at Siracusa/Syracuse. I’m the P.I. of this work (since it’s my primary field of interest), and David Scahill (from question #1 above) is a contributor / collaborator. I have some facilities at UNL to support the project; mainly computer and camera hardware at this point, and I plan to develop a website for the project when I am ready to disseminate the 3D date over the Internet.

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Photoscan work. Photo: Philip Sapirstein

Question – What are the main keys, in your opinion, to focus on a digital project like this?
Answer – I suppose there are many possible answers that will depend on the project. In the case of the DAP / photogrammetric work at Olympia, my main concern was in producing 3D models with the objective of answering specific research questions. In this case, I was aware of many reasons for challenging the idea that the Hera temple had a wooden colonnade before I started the project, but I needed to study the building very carefully to make this argument. Photogrammetry is a new and very powerful recording technique, and so in 2013 and 2014 I learned how to get it working at a big monument like the Heraion and controlling its accuracy so I could rely on the measurements (which have an internal consistency of +/- 1mm throughout the 25 x 55 m building site in the 3D model). While making the models and examining the results in 3D, I noticed other things I hadn’t expected, which is why I am working on multiple new projects.

In sum, the 3D modeling was started in service of a preexisting major research problem (did the Hera temple have wooden columns?), and I chose photogrammetry as likely to be the most efficient and effective way of showing the answer to this question. However, this also required developing innovative methods for deploying photogrammetry on such a large site, and once I had the 3D models David Scahill and I both noticed new, unexpected things about the building which will result in other publication.

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Reconstruction of the roof from the Heraion at Mon Repos. Photo: Philip Sapirstein

Question – In the context of the Digital Archaic Heraion Project at Mon Repos, you have digitalized a total of 550 catalogued fragments excavated at the Mon Repos sanctuary, on display in the Archaeological Museum of Corfu right now. The majority inaccessible to the public, only in your project’s web. Once digitalized, you have analyzed and reconstructed the temple. This is a great project, not only for professionals, but also to the public. Please, could you explain briefly which techniques did you use and how did you manage the project?
Answer – That was an earlier research project. The Heraion at Mon Repos, Corfu, is slightly earlier than the temple at Olympia (Corfu would be about 610 BC, possibly a bit earlier, and stylistically is quite different from Doric architecture). I received an ACLS Digital Innovation Fellowship in 2010-11 to digitize all the architectural fragments from the temple; over 300 are terracotta tiles and sculptures from the roof, and the rest are small stone pieces from the building. In 2010, the type of photogrammetry software I used at Olympia was still being developed, and previous types of photogrammetry software were not suitable to the task of recording 550 fragmentary objects ranging in size from a few cm across up to about 1m. So instead I rented a compact laser-scanner (by Creaform, called a VIUScan though this model is no longer produced) for the job. When modeling large numbers of objects, a laser scanner is still more efficient than even today’s photogrammetry software, because you can produce each model a little faster with the scanner and time per model matters a lot more when you have hundreds to do.

There should be plenty of information about the project on the website; I have left some sections “under construction” because I intend later to publish a book on the full architecture of the building which will add new information. But I think that will be at least a couple years from now before I can complete it. For now, there is a long Hesperia article from 2012 describing and reconstructing the roof (which is the best preserved part of the temple) and all the fragments can be seen on the website too. I also intend to update the website, which for example uses Flash—which was the only way to display the 3D models in 2010—but can now use newer and more efficient techniques for embedding high resolution 3D models.

Question – Do you think it is possible to combine the use of complex 3D technologies for research with divulgation purposes?
Answer – The Mon Repos website is an example of what I’d like to do in the future for the dissemination of 3D models. It’s important to prepare the 3D scans so that they can be viewed on the web. The original files are very large and unsuitable for a browser. I put a lot of work into developing technology for Mon Repos to be able to display the models in 3D (back in 2010, like I wrote in the previous question, only writing custom Flash software could do this effectively), and I also had to simplify all the models so they could be downloaded quickly by users. I am hoping to do this for Olympia too, but this is an even bigger undertaking. The 3D models of the Hera temple are massive: dozens of gigabytes of raw data, and even displaying the whole model is impossible on the current generation of graphics cards. So the data must be downsampled significantly. There’s also the question of how to navigate the whole building, and what sorts of related information to include. This is another future project I intend to do over the coming years.

Autor

Mario Agudo Villanueva