Satellite imagery only goes back so far. To measure the rate of ice loss across the Himalayan glaciers, researchers turned to recently declassified spy satellite photos from 1975. The photos were used to create a digital elevation model (above) which was compared with more recent data. They concluded that the rate of ice loss was accelerating: it was twice as much from 2000 to 2016 than it was from 1975 to 2000. Columbia University, Science News. [Geography Realm]
In The Atlantic’s May 2019 issue, Frank Portnoy looks at an unexpected use of satellite imagery: stock analysts counting cars in retail parking lots, among other things, to predict a company’s revenues.
Here’s a silly Google Maps origin story about how “Satellite” was almost named “Bird Mode” pic.twitter.com/wj7CRJUEyx
— Bret Taylor (@btaylor) February 23, 2019
A lot of what we refer to on online maps as “satellite imagery” actually isn’t: the high-resolution stuff is usually taken from airplanes. This can be a point of confusion for some—and, according to this Twitter thread from Google Maps co-creator Bret Taylor, also a point of contention for the Google Maps team before it launched. Some engineers felt that calling the layer “Satellite” was factually incorrect—because of that aerial imagery—and therefore shouldn’t be used; others argued for “Satellite” based on label size and usability studies. It nearly got called “Bird Mode” as a compromise. [Boing Boing]
Pierre Markuse’s Satellite Image Guide for Journalists and Media:
So you would like to use a satellite image in your article and you would like to explain it to your viewers? Here is a short guide covering some of the most frequently asked questions and giving some general explanations on satellite images. It by no means covers all aspects, as there are far too many types of satellite images, but should give you a good start to find out more on your own and maybe motivate you to create your own images, which has become quite easy and quick even with no prior knowledge of it.
Complete with examples of imagery, examples of how to use it properly, and links to resources.
The San Francisco Chronicle’s 2018 California Fire Tracker is an interactive map of ongoing and contained wildfires—notably, at this moment, the Camp and Woolsey fires. It includes fire perimeter and air quality data. (Note: it’s glitchy on desktop Safari.)
The Jet Propulsion Laboratory has produced a map of the damage from the Camp Fire based on satellite radar images. NASA Earth Observatory has maps and animations showing the impact of the Camp Fire on air quality and satellite images of the Woolsey Fire burn scar.
Last week a magnitude-7.5 earthquake struck the Indonesian island of Sulawesi, triggering a tsunami that struck the city of Palu with far more force than expected. The New York Times has multiple maps and aerial images of the damaged areas; NASA Earth Observatory has before-and-after Landsat imagery.
Landsat observations have charted the erosion of the banks of the ever-changing Padma River, a major distributary of the Ganges in Bangladesh. This is vividly shown in this animation produced by NASA Earth Observatory, which “shows 14 false-color images of the Padma river between 1988 and 2018 taken by the Landsat 5 and 8 satellites. All of the images include a combination of shortwave infrared, near infrared, and visible light to highlight differences between land and water.” More on the erosion of the Padma River here.
The Washington Post maps the largest of the wildfires burning in northern California: the Carr Fire threatening the city of Redding and surrounding communities. The Redding Record Searchlight has drone footage of the destruction wreaked by the Carr Fire in Shasta County. NASA has natural and false-colour imagery (Earth Observatory, Visible Earth) of the Carr Fire, as well as the Ranch and River Fires to the south, the so-called Mendocino Complex. See the Mercury News’s fire map of the Mendocino Complex, whose two fires’ combined acreage is now larger than the Carr Fire. Meanwhile, German astronaut Alexander Gerst observed the California wildfires from the International Space Station. [San Francisco Chronicle]
Daily Overview is a website that curates spectacular aerial and satellite imagery. Founded by Benjamin Grant, and inspired by the Overview Effect—”the sensation astronauts have when given the opportunity to look down and view the Earth as a whole,” it’s available in virtually every social media format out there; a book, Overview, came out in October 2016. [WMS]
Last October Robin Kraft posted an online map of the northern California wildfires showing satellite imagery from before and after the fires (see previous entry); today he’s posted a blog entry explaining how he built it, in great technical detail. The timing is not accidental: “There is another fire raging in Los Angeles right now — if DigitalGlobe and Planet release their data, you can use this guide to make your own map.”
There are many circumstances where the amount of data vastly exceeds the ability to process and analyze it—and computers can only do so much. Enter crowdsourcing. Steve Coast points to Digital Globe’s Tomnod project, which basically crowdsources satellite image analysis. In the case of the current project to map the presence of Weddell seals on the Antarctic Peninsula and the ice floes of the Weddell Sea, users are given an image tile and asked to indicate whether there are seals in the image. It’s harder than it looks, but it’s the kind of routine task that most people can do—many hands, light work and all that—and it helps researchers focus their attention where it needs focusing. (A similar campaign for the Ross Sea took place in 2016.)
Another ongoing campaign asks users to identify flooded and damaged infrastructure and trash heaps in post-Hurricane Maria Puerto Rico.
This NOAA article looks at three kinds of imagery provided by the GOES-16 geostationary weather satellite: GeoColor, the Geostationary Lightning Mapper (!), and full disk infrared imagery from the Advanced Baseline Imager. GOES-16 launched last November and is currently in the checkout phase before it replaces GOES-13 at 75° west latitude.