Saturday, July 20, 2024

Inside the outrageously ambitious plan to scan the entire Earth with lidar


Lidar technology is the remote sensing tech that allows self-driving cars to perceive their surroundings. Working in a similar way to radar and sonar, but using light waves rather than radio or sound, lidar sends out laser pulses and then measures how long it takes to bounce back. In doing so, it allows autonomous or semi-autonomous cars to create 3D models and maps of their environment, thereby making sense of the world around them.

So far, so familiar, right? An ambitious new project from two professors at Colorado State University wants to use the same technology to also make sense of the world — only instead of just making sense of the world directly around them, they want to make sense of the entire world — by using lidar to scan the total surface area of planet Earth. And they’re in a hurry to do it, too.

NASA Earth Observatory images by Jesse Allen

“The Earth is changing so quickly that we have limited time to create these 3D records that can be preserved for future generations,” Dr. Chris Fisher, professor of archaeology at Colorado State, told Digital Trends. “This is truly the ultimate gift that we can leave for future generations.”

Fisher has teamed up with geographer Steve Leisz to launch what they call The Earth Archive. The idea, as Fisher notes, is to use lidar scanning to generate maps of cultural, geological and environmental artifacts that are at risk in the face of climate change. They believe these will be useful for future scientists.

Supercharging archaeology

“I’m an archaeologist that has been using lidar technology for a long time to find archaeological sites and landscapes,” Fisher explained.

This use of lidar is far less well-known than its deployment in self-driving cars. But the results are no less impressive. In summer 2016, lidar was used to create a map of a long-lost city hidden beneath jungle cover in Cambodia. The lidar system deployed in that instance made it possible to “look through” obstructing features such as trees and vegetation to map the ground underneath.

Fisher carries out similar work. However, as he points out, as he sifted through the data gathered for his work, he concluded that much of what he was discarding as irrelevant for his research could be extremely relevant for others. “I practice what I call ‘digital deforestation,’ scrubbing away the vegetation to unveil the archaeological materials below,” he said. “But all of those data I digitally clean away are the careers of hundreds of other scientists. When I realized this it also became clear that these lidar records represent the ultimate conservation tools in that they record the Earth’s surface and everything on it.”

NASA Earth Observatory image by Jesse Allen

Unlike the on-board lidar scanners in autonomous vehicles, the lidar systems used by archaeologists tend to be more, well, involved. In the case of the lost Cambodian city, the scans were made using a helicopter with a lidar rig installed on its underside. Meanwhile, on The Earth Archive website, it references using an airplane to shoot a “dense grid of infrared beams … towards the ground.”

By carrying out fly-by passes, several hours of coverage can achieve what would otherwise require literally decades of on-the-ground surveys — and with far greater levels of accuracy. The results do much more than simple images as well; the high-resolution scan provides researchers with a dense cloud of points which can map objects in three dimensions.

Like a three-dimensional Google Earth

There are three phases to The Earth Archive project. The first step is to create a baseline record of the Earth as it is today. The researchers argue that the only way to truly measure climate crisis-induced change is to have two sets of data — a “before” and “after” — data set that can be analyzed. Right now, no high-resolution “before” data set exists for most of the planet. As a result, scientists cannot be sure exactly how things are changing and whether interventions are yielding positive results.


The second step is to then build a virtual, open-source model of the planet that’s accessible to all scientists who want to access it. Picture it as a three-dimensional Google Earth. Archaeologists might want this to search for undocumented settlements. Ecologists, meanwhile, could use it to look at forest compositions. Geologists could use it to study things like hydrology, faults, and disturbance. “The possibilities are endless,” the researchers note.

The final step is to develop other A.I. tools which can analyze the lidar data in ways that cannot currently be conceived of.

“We hope to make the date it accessible to as many scientists in other interested stakeholders as possible we may not be able to truly open source the data, but we can certainly make it widely available,” Fisher said. “That means that we really can’t tell how the data will be used in the future. We can only guess — but it will undoubtedly be critical.”

As best we can, as quickly as we can

Critical appears to be the crucial word here. The researchers note that 50% of the world’s rainforests have already been lost, 18 million acres of forest is destroyed each year, and rising sea levels threaten to render cities, countries and continents unrecognizable. “Unless we have a record of these places, no one in the future will even know they existed,” the project website notes. Starting the scanning process is therefore a matter of urgency.

NASA Earth Observatory image by Jesse Allen

“As best we can, as quickly as we can,” Fisher said, describing the path forward. The project is starting with the Amazon which, he explained, “we believe we can scan for $15 million.” Consisting of 5.5 million square kilometers (more than half the size of Canada) that would be an amazing start. But it’s just a fraction of the 148 million square kilometers that is the Earth’s non-ocean land mass. (There’s considerably more if they plan to scan water, which lidar can also be used to probe.)

“[If people are interested] they can tell their friends and neighbors,” Fisher continued. “They can support science generally, and they can pressure their representatives to move forward with solutions to the climate crisis. They can also visit and leave a donation or lend support. Right now, The Earth Archive is corporate and government-neutral, so we depend on the kindness of donations to get our work done.”

Read more

More News