Lost cities / archaeology / ancient history

A very interesting and under-investigated Roman-era site is Viroconium, today near the present-day village of Wroxeter.

https://en.wikipedia.org/wiki/Viroconium_Cornoviorum

Here, you see the enormous progress from old-style archaeological research methods to modern ones, mainly remote sensing. Before the advent of computers, everything had to be done laboriously by hand, but as you can see here, even early computer methods, while endearing from today's perspective, were pretty crude

https://www.cs.bham.ac.uk/~slb/arch/arch1992.html

Magnetic gradiometry is a long-established technique to find evidence of archaeological remains, to map sites and to decide where to excavate if at all:

https://www.researchgate.net/publication/229880426_Large-scale_systematic_fluxgate_gradiometry_at_the_Roman_City_of_Wroxeter

This survey was very interesting, because contrary to previous assumptions, it suggested that Viroconium was completely built-up within its walls and not a lightly-settled 'garden city'. (As I've often said, I think that we have systematically under-estimated ancient populations, and I'd be surprised if Viroconium had 'only' the 15,000 inhabitants that have traditionally been estimated for it.)

However, even this is laborious compared to LIDAR. A few years ago, Wroxeter was LIDARed:

https://nitter.snopyta.org/markwalters_/status/830867293160751110

While this is a great tool, its main use so far, it seems to me, is in dense vegetation such as the Mayan jungle, where it has had very impressive results in bringing out contours of ancient man-made features hidden by the jungle. It is clearly useful in revealing large-scale earthworks even where there isn't much vegetation cover, but it doesn't seem to reveal much where a site is covered by soil, as in Viroconium.

The most fascinating kind of remote sensing, to me, is still the work of Sarah Parcak et al., as posted before:

In Egypt, her specialty area, she and her team have expanded the civilization’s known scope, spotting more than 3,000 ancient settlements, more than a dozen pyramids and over a thousand lost tombs, and uncovered the city grid of Tanis, of Raiders of the Lost Ark fame. After the Arab Spring, in 2011, she created, via satellite, a first-of-its-kind countrywide looting map, documenting how plundered tombs first appeared as little black pimples on the landscape and then spread like a rash. She has pointed out the ruins of an amphitheater at the Roman harbor of Portus to archaeologists who had spent their whole careers digging above it, mapped the ancient Dacian capital of what is now Romania, and—using hyperspectral camera data—aided in the ongoing search for prehistoric hominid fossils in eroded Kenyan lake beds.

https://www.smithsonianmag.com/innovation/space-archaeologist-sarah-parcak-winner-smithsonians-history-ingenuity-award-180961120/

It's just spectacular.

The maps these techniques produce are so accurate that I think they're reluctant to publish them for fear of aiding looters. She has mapped looting this way, too:

https://www.theguardian.com/science/2019/jul/27/sarah-parcak-interview-arcaeology-from-space-satellite-imaging-globalxplorer-project-ancient-egypt

The highest resolution satellite imagery we have right now is 0.3 metres. In the next five to 10 years, I’m expecting that to get down to about 0.1 metres.

I do hope that this sort of work will at some point be applied to Roman Britain, because I think we're in for a few surprises there.

Still, sometimes things are revealed by just a dry spell:

https://www.shropshirestar.com/news/2013/08/03/site-of-roman-house-revealed-in-shropshire-hot-spell/