Luftbildarchäologie
August 20, 2018 2:17 PM Subscribe
During this year’s long heatwave in Britain and Ireland, many people’s imaginations have been captured by the images of archaeological sites revealed in parchmarks (previously in Wales and also in Ireland).
As the summer draws to an end, archaeologists are beginning to take stock of dozens of new sites that have been uncovered. You may think that archaeologists mainly dig, but getting up in the air is one of the most important methods for identifying archaeological sites.
From the air, sites show up in several different ways:
Parchmarks, and their mirror-image cropmarks are caused as the soil dries out, or retains water, at different rates, causing the ground cover plants to germinate, grow and die at different rates. (Good explainer from RCHMWAS, shared in the Welsh post previously)
Shadowmarks show slight differences in the ground level, when the sun is low and different angles may show different features. Snow can help highlight features, and melting snow and frost can highlight raised banks, stone walls and shallow ditches.
Slight differences in soil colour which sometimes show up during ploughing are known as soil marks.
The first aerial shots of an archaeological site were taken in 1899 by Giacomo Boni from a hot-air balloon of the Forum in Rome.
You don’t need a plane, many of this year's images were taken with drones. But low-cost methods with kites work just as well, and were pioneered in the 1910’s by Henry Wellcome in South Sudan. He was working with O. G. S. Crawford, who went on to develop aerial archaeological methods after his time being involved with aerial reconnaissance in WW1, and identified the extent of the Stonehenge Avenue from RAF photos.
Many sites have been identified by pouring over photos taken for other purposes, including Ordinance Survey mapping and RAF photos from training flights in the the 1940s and 50s, some of which you can view online at the Cambridge University Collection of Aerial Photography (CUCAP) – along with thousands more images.
Many notable sites have been identified using aerial archaeology. But cropmarks show up differently each year, so new discoveries on well-known sites are always possible, even on well known sites, as this year has aptly shown.
Aerial photography is just one form of remote sensing from the air used by archaeologists, thermal imaging, LiDAR, and satellite imaging are common tools.
Want more pictures? See here from the Guardian, explore Historic England’s aerial photography information and pictures , and hunt for sites yourself on Britain from Above .
From the air, sites show up in several different ways:
Parchmarks, and their mirror-image cropmarks are caused as the soil dries out, or retains water, at different rates, causing the ground cover plants to germinate, grow and die at different rates. (Good explainer from RCHMWAS, shared in the Welsh post previously)
Shadowmarks show slight differences in the ground level, when the sun is low and different angles may show different features. Snow can help highlight features, and melting snow and frost can highlight raised banks, stone walls and shallow ditches.
Slight differences in soil colour which sometimes show up during ploughing are known as soil marks.
The first aerial shots of an archaeological site were taken in 1899 by Giacomo Boni from a hot-air balloon of the Forum in Rome.
You don’t need a plane, many of this year's images were taken with drones. But low-cost methods with kites work just as well, and were pioneered in the 1910’s by Henry Wellcome in South Sudan. He was working with O. G. S. Crawford, who went on to develop aerial archaeological methods after his time being involved with aerial reconnaissance in WW1, and identified the extent of the Stonehenge Avenue from RAF photos.
Many sites have been identified by pouring over photos taken for other purposes, including Ordinance Survey mapping and RAF photos from training flights in the the 1940s and 50s, some of which you can view online at the Cambridge University Collection of Aerial Photography (CUCAP) – along with thousands more images.
Many notable sites have been identified using aerial archaeology. But cropmarks show up differently each year, so new discoveries on well-known sites are always possible, even on well known sites, as this year has aptly shown.
Aerial photography is just one form of remote sensing from the air used by archaeologists, thermal imaging, LiDAR, and satellite imaging are common tools.
Want more pictures? See here from the Guardian, explore Historic England’s aerial photography information and pictures , and hunt for sites yourself on Britain from Above .
I am so excited about crop marks. Find all the things!
posted by corb at 3:27 PM on August 20, 2018 [1 favorite]
posted by corb at 3:27 PM on August 20, 2018 [1 favorite]
This is so amazing.
posted by rtha at 4:09 PM on August 20, 2018 [1 favorite]
posted by rtha at 4:09 PM on August 20, 2018 [1 favorite]
Very cool. I’m surprised no kid went out there with a watering can to trace a giant penis.
posted by bonobothegreat at 5:44 PM on August 20, 2018 [1 favorite]
posted by bonobothegreat at 5:44 PM on August 20, 2018 [1 favorite]
This is the coolest.
posted by pracowity at 5:32 AM on August 21, 2018 [1 favorite]
posted by pracowity at 5:32 AM on August 21, 2018 [1 favorite]
I love stuff like this. It's astonishing how the ground, once disturbed, stays disturbed, even (tens of) thousands of years later. We humans really do leave our mark.
posted by orrnyereg at 8:44 AM on August 21, 2018 [1 favorite]
posted by orrnyereg at 8:44 AM on August 21, 2018 [1 favorite]
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Oh man why do I have to be at work rn this is so much cooler than the crap I am doing
A+ post, Helga-woo
posted by Hermione Granger at 2:45 PM on August 20, 2018 [6 favorites]