Introduction to the Hippos Excavations
My name is Michael Eisenberg, I’m a senior researcher and a lecturer at the University of Haifa, Israel where I work at the Institute of Archaeology and teach at the Department of Archaeology.
My main field of interest is Classical Archaeology in the wider perspective. My main research focus is military architecture and the art of siege warfare during the Classical, Hellenistic and Roman periods.
I’ve been excavating for quite a long time now in various sites but my second home, for the last 20 years now, is the ancient city of Antiochia Hippos of the Decapolis.
This marvelous site is located to the east of the Sea of Galilee, overlooking the sea and the eastern Galilee from the top of a mountain.
As the director of the Hippos Excavations Project I am in an endless pursuit of high quality documentation of the site, finds in the field and lab and then the working process itself. Being a professional photographer I benefit from both worlds and usually conduct the main photography-based documentation by myself. Such documentation is vital in field archaeology, even more than in general heritage documentation or in the lab, as you won’t get another chance to capture the moment when the artifact was unearthed. Capturing the moment is vital in many cases in our field; sometimes its significance is appreciated only years later as part of the post-field analysis or while preparing an exhibition.
Using 3D on the Excavation
3D model-based documentation arrived to our field around 6 years ago and since then has become part of our field routine up to the point where most of the manual and machine based measurements and drafting are no longer needed. The main use of the measurement machinery nowadays in the field is to supply ongoing height differences while excavating and provide accurate positioning, up to 1 cm accuracy, for setting up the markers for the 3D model at each field.
Excavations are conducted usually just for one main season a year, about a month long. Most of the team is coming from around the globe; English is the official expedition language as well as the language used for the database (based on Ochre from the University of Chicago). Within the frame of this DB and on local servers we upload terabytes of digital photography files each season. Photogrammetry is becoming a vital part of our daily life at the site, and starts with:
- Ground photography: excavation area, excavation squares and section, architecture and small finds.
- Aerial drone-based photography: recently became a routine up to the point that I’ve decided to purchase my own drone (DJI Mavic Pro II). It is used not only to document full large-size sites like Hippos, but also the excavation areas, architecture and as an efficient contour and survey tool. In some cases, areas in the region are mined, so the only way to survey them is with a drone.
In 2014 our institute opened a photogrammetry lab and a local specialist was in charge of creating the models while using mainly Agisoft software. The results eventually were between very good to excellent. Slowly I became familiar with the modeling requirements in the field and lab photography, but recently I’ve decided to enter deeply into the field and control the entire process. We have purchased the Bentley ContextCapture software and it is now the main tool I use after having switched to more powerful computers. The Bentley allows a better free viewer for measurements, which allows team members to access them and use them for writing the reports and publishing; not only do we create field models but also models of small finds in the lab or architectural elements in the field.
I recall becoming familiar with Sketchfab through our previous lab manager Eli Gershtein who taught me how to upload and share the models on our web sites.
How the Hippos Excavations use Sketchfab
Sketchfab, as an open internet 3D models portal, was used mainly in two ways: in class while teaching and as a general free media for popular media and marketing. I recall the first time Sketchfab personnel got in touch with me after we published worldwide one of the most unique finds in Classical Israeli archaeology: the bronze mask of Pan which hit some of the major media in the world. It was the first time I decided to incorporate a link to our model of the ancient gate where the mask was found (at the early stages of exposure) and it became super popular.
Since then we have used Sketchfab rather often while linking to our Facebook page or sending direct links to professionals to allow them to assess our research conclusions (sometimes even supplying with links in academic papers) or to government parties like the Israeli National Parks Authority.
Sketchfab is a great didactic tool to use in class, whether using your own models or those created by others, mainly of larger ancient sites. Very recently I was amazed at the ease of creating (I must admit it was mainly for fun) an almost full size simple drone-based didactic model of one of the largest ancient sites in Israel—Nysa Scythopolis. The model was so successful that the NPA (National Parks Authority) representatives and many of my professor colleagues wish to use it.
3D for Research and Display
A recent fire (September 2019) next to our excavation site at Hippos encouraged us to undertake an immediate drone-based documentation of the area, post-processing it while looking for undiscovered ancient features. My PhD student Adam Paout recently carried out similar documentation along a Roman road, discovering an unknown Roman tower.
Curation is part of my interest and recently (December 2017-present) I have curated the first exhibition to expose Hippos to the public, at the Hecht Museum, University of Haifa. In the running screen of the exhibition we have incorporated several models from the field and a model of the mask of Pan. Similar use was conducted by my Japanese colleague Ezo Makoto and his very recent 3D documentation at our labs (Agisoft based) will be part of a small exhibition in Tokyo.
Lab 3D modeling is beneficial not only for representations in classes, conferences and the popular media but also for documentation and analysis. Measurement accuracy of many small artifacts is improved through the use of computer implementation. In some cases we wish to create a full, very accurate model to be used for 3D printing devices. This stage of the process needs to be refined; in many cases problems arise with some artifacts but the solutions are just around the corner.
3D in archaeology is already a basic tool. During our last excavation season at Hippos (July 2019) 3D models became an almost daily procedure when needed. In September 2019, a ‘Burnt Church’ with its mosaic carpets was published in the world media. As we speak, the area supervisor Jessica Rentz from the US, is using the shared 3D models of the church, its mosaic, and some of the rooms in order to establish measurements, capture photos from the model, and finalize her report.
Challenges in 3D Capture
The major obstacles in 3D capture are the quality of the lens and camera used for photography; miniature lenses with 1” CMOS (i.e. Mavic 2) are fine but don’t expect to have profesional results. Full frame cameras (I use the Canon 5D-IV) with full size sensor and pro lenses will overcome most of the distortions and many medium format cameras (we use Phase One 645DF with 50 MB back) will supply a very high image standard with more than a decent dynamic range factor.
In this sense we are actually compromising and eventually the results are by far less professional than standard still photography was a decade ago. Improved photography and model quality may be obtained via technology or by using very expensive drone-based cameras, which are not always permitted or handy.
It is clear that in my scholarship more and more 3D models will be created in the field and lab, allowing for Sketchfab users to study, enjoy and just have fun with this kind of reality. Perhaps, an obstacle that my professional colleagues will have to overcome is becoming comfortable with increased exposure on Sketchfab and the like—allowing a fuller view and review into your own dig is not always warmly welcomed.