In February of 2018, the mainstream press was abuzz with the news that a group of researchers had lidar-scanned large swaths of the Maya reserve in Guatemala, and made a number of huge discoveries while poring over the data. Funded by the Guatemalan nonprofit the PACUNAM Foundation, the researchers were able to strip the trees out of the point clouds and find upwards of 60,000 new structures, as well as a large number of agricultural systems, earthwork ditches, and rampart systems. The settlement turned out to be a great deal more complex than anyone imagined.
One of those researchers is Ithaca College archaeologist Thomas Garrison, a keynote presenter at the International LiDAR Mapping Forum this month in Denver, CO. (Register here!) I caught up with him ahead of the conference to discuss the ways lidar is changing the age-old discipline of archaeology, why researchers need lower-priced systems as quickly as vendors can make them, and a few other details about the project you might not have picked up in the press coverage.
SPAR 3D: Given the scale of this discovery, it seems like the coming of lidar to archeology represents a huge historical turning point.
Garrison: I’d say yes and no. One of the big misconceptions we’re noticing is that people see the images and they say, “Why don’t you go check out that site?” Well, because we only digitally took off the forest—we still have to get there.
For us doing the field work, it’s a blessing to have the data because we’re not just setting out and hoping we’re going to find something that day. When I started out in this back in the early 2000’s using multi-spectral satellite imagery, some days we’d get to a place where we saw a little discoloration in the vegetation, and there would be ruins there. Some days we’d walk and we wouldn’t find anything. Now, you’re going to reach what you’re looking for, but the journey to get there has not gotten any easier. You know, I wouldn’t want it any other way. For many of us that get into the field of archeology, the most exciting part of it is doing the field work.
So technology can only do so much, and there’s no replacing the actual field work. That seems like a sentiment a lot of lidar users can relate to. However, it seems like the specific technology you’re using makes a huge difference in archaeology.
I think one of the things that stood out to us is that the actual sensor you’re using matters. You know, this is stuff that has been worked out by the National Center for Airborne Laser Mapping, who’s done a number of flights with different sensors over different parts of the Maya area. The original studies were done with this Teledyne Optech Gemini and ours is with the Teledyne Optech Titan. The Titan just had a so much more powerful laser, and it’s collecting that much more data, and it’s letting us see more subtle features. The lasers are getting in at different angles, which is getting us better returns. Those are things that people that aren’t as familiar with the actual sensor side of things aren’t necessarily realizing, like those in my field.
Do you have any future wants or needs from lidar technology?
The thing that’s always going to cause problems is the cost, right? And it’s not just the cost of the sensor. You know, the archeologists aren’t the people that are out there flying the plane, collecting the data, getting it off the instrument, calibrating it, and running the algorithms, so that costs archaeologists lots of money.
In my field, we’re in this awkward phase where a lot of us now do have access to lidar, but there’s still more than 90 percent of the Maya area that hasn’t been covered with this stuff. What we’re finding is that every single place where we get lidar, it’s just a totally different world than anything we thought before. So now it creates this research problem where if you don’t have lidar, what can you really say about the settlement in your area? But it’s not reasonable to expect everyone to get lidar. Because of the cost.