MapLab: High on Lidar

Lidar is similar to radar, except that it uses laser beams (rather than radio waves) to detect objects in space. It can produce far more detailed pictures of its subjects than its older cousin because it captures the speed at which its lasers bounce back to their origin.

The technology is a critical component of autonomous vehicles, and it has also made waves in the world of science and history. Just a few weeks ago, the New York Times ran a story about an Arizona archaeologist who discovered Mayan ruins that had never been seen by the modern world by trawling lidar imagery in the public domain.

A snapshot of a lidar scan of the Peruvian Amazon rainforest. (Carnegie Airborne Observatory)

That type of discovery may become more achievable through Earth Archive, a project by researchers at Colorado State University that aims to create comprehensive maps of the planet’s surface, using lidar. The hope is to etch a permanent record of Earth’s cultural, environmental, and geological resources, with so many of them now facing destruction by humans or human-induced climate change.

“We are going to lose a significant amount of both cultural patrimony—so archaeological sites and landscapes—but also ecological patrimony—plants and animals, entire landscapes, geology, hydrology,” Chris Fisher, a CSU archaeologist and the project’s founder, told the Guardian this month. “We really have a limited time to record those things before the Earth fundamentally changes.”

In 2018, scientists at the National Center for Airborne Laser Mapping captured 3D images of the Maya settlement of Tikal using lidar technology. (National Center for Airborne Laser Mapping/University of Houston)

Fisher was originally inspired by CyArk, a nonprofit group that creates 3D records of cultural monuments and sites using laser scanning. With a focus on the 29 percent of the Earth’s surface that is land, the project is meant to create an open-source encyclopedia of granular lidar data to inform scientists across disciplines. Areas that are facing the greatest threat of destruction, such as coasts sinking beneath rising sea levels and the rapidly disappearing Amazon rainforest, will be the first to get scanned.

Some scientists are skeptical that the idea can take off, citing logistical, political, and cost concerns. Fisher guesses that a lidar map of the Amazon alone would require $15 million and at least three years. Scanning the entire planet in an aircraft would take decades to complete. But Fisher says the results would be an indelible document for future scientists—and all humans.

“It is for their grandchildren, and their grandchildren, and their grandchildren,” he told the Guardian. “[It’s like] the ultimate gift we can give to future generations.”

How L.A.’s map librarian learned to love maps

In the latest installment of the Maps That Make Us, CityLab’s ongoing essay series about the power of maps to shape public and private life, Glen Creason writes about his struggles to care about his cartographic charges in his early days as map librarian at the L.A. Public Library. Then he stumbled on a 1942 pictorial map of Los Angeles by Joseph Jacinto Mora.

Historical and Recreational Map of Los Angeles, by Joseph Jacinto Mora. (Los Angeles Public Library)

In brilliant color, the map touches on numerous elements of L.A.’s modern history and development, Creason writes, as well as its geography and culture. Like a lot of popular imagery in Mora’s age, it fails to depict people of color in anything but servile roles. But the map also places an unusual emphasis on how “regular (if white) folks” shaped the city, as opposed to big-wig politicians, bankers, or influential families, Creason writes. He continues:

Thirty years later, I still do not get moony over stacks of nautical charts. But I do remember that the blue in their oceans signifies something grand, the sort of feeling that Mora was so good at evoking and that transforms an otherwise dry image into something more than good gift-wrapping paper. Since encountering Mora’s work, I can look at all forms of cartography with greater appreciation. I even dream about maps. (To be honest, I have nightmares where I can’t find them.)

Read the full essay here.

Mappy links

Speaking of mapping the planet, there are multiple initiatives underway to map the entire seafloor. (Maritime Executive) ♦ University of Chicago researchers are tracking informal neighborhoods in Africa in order to connect them to infrastructure. (University of Chicago) ♦ Google Maps now shows speed traps, but law enforcement isn’t pleased. (Washington Post) ♦ A profile of the woman behind the world’s largest map retailer. (BBC)

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Stay spooky, my friends,

Laura Bliss

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