Another lost city found
There’s an interesting, albeit quite short, article in the current issue of Science entitled The Map of Altinum, Ancestor of Venice by Andrea Ninfo et al. If you can’t access the full text version, you might want to look at the ScienceNOW article — which is, incidentally, at least as long as the actual article — to see their figures. As they note, there are no ruins of Altinum; all of that has been robbed out or lost naturally over the years. Their map of the city, then, is based entirely on cropmarks observed in multispectral aerial photographs, and their results are fairly striking.
What makes those results striking isn’t the spatial resolution of the imagery — 50 cm multispectral satellite imagery isn’t available, but there are several commercial satellites with that kind of resolution in the panchromatic band; even in 2007, when the authors’ imagery was obtained, QuickBird approached this kind of resolution — but the fact that the authors were able to obtain imagery of the area under ideal circumstances. This isn’t exactly a new insight — archaeologists since O.G.S. Crawford have pointed out that the conditions under which aerial photographs are taken can have profound effects on what is visible in the images — but it’s still good to keep in mind. In one sense, this is a good argument for using aerial photography, since it’s fairly easy to control when the photographs are taken, but there’s also a good argument for satellite imagery in here. If you happened to know that the crops in this area were particularly stressed in July 2007, but didn’t manage to get a plane up to take pictures for you, it wouldn’t be particularly difficult to find satellite imagery from July 2007.
This type of study isn’t new, but they’ve done a really thorough job so far of creating the map of the city. As I mentioned, it’s a very short article, but I’m definitely curious to see what will come of this, and how they’ll integrate the work they’ve done so far with the excavations that are presumably to come.
2009 Ninfo, Andrea, Alessandro Fontana, Paolo Mozzi, and Francesco Ferrarese. The Map of Altinum, Ancestor of Venice. Science 325(5940):577. DOI: 10.1126/science.1174206