Mapping the Sulawesi Earthquake and Tsunami

The New York Times (detail)

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.

The Changing Padma River

Padma River erosion animation
NASA Earth Observatory

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.

Mapping the Northern California Wildfires

Washington Post (screenshot)

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]

How to Build a Fire Map

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.”

Crowdsourced Satellite Image Analysis

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.

A Look at GOES-16’s Imagery

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.

Mapping the Northern California Wildfires

NASA Earth Observatory
NASA Earth Observatory

Maps and satellite imagery of the wildfires in Northern California include the San Francisco Chronicle’s interactive map; Robin Kraft’s interactive map  showing satellite imagery from before and after the fire; this New York Times page mapping building damage in Santa Rosa; the Washington Post’s coverage of the devastation; and NASA Earth Observatory’s images of the smoke plumes here and here.

Mapping the Earthquake in Central Mexico

The New York Times

This crowdsourced map of collapsed and damaged buildings in Mexico City (in Spanish) appeared shortly after the 7.1-magnitude earthquake hit central Mexico on 19 September [via]. NASA also produced a map, based on radar data from the ESA’s Copernicus satellites that compared the state of the region before and after the quake. Interestingly, the data was validated against the crowdsourced map.

The New York Times produced maps showing the pattern of damage in Mexico City and the extent and severity of earthquake shaking (the Times graphics department’s version of the quake’s Shake Map, I suppose) as well as how Mexico City’s geology—it was built on the drained basin of Lake Texcoco—made the impact of the quake much worse.

Esri Makes Satellite Imagery Available to OpenStreetMap Editors

Esri is making its satellite imagery collection available to OpenStreetMap editors.

Today Esri is proud to announce that we are making our own global collection of satellite imagery available to the OSM community directly through our existing World Imagery Service. This regularly updated resource provides one meter or better satellite and aerial photography in many parts of the world, 15m TerraColor imagery at small and mid-scales (~1:591M down to ~1:72k), 2.5m SPOT Imagery (~1:288k to ~1:72k), 1 meter or better NAIP in the US and many other curated sources, so we know it will make a welcome addition to OSM’s growing catalog of reference layers.

OSM editors have been able to trace maps from satellite imagery for years; other sources of such imagery have included Bing and Yahoo (back when Yahoo Maps was a thing). Different sources have different strengths, so this can only help the project. (Esri’s imagery makes no difference where I am, but that’s not a surprise.)

NASA Images of Hurricane Harvey

Hurricane Harvey on 26 Aug at 5:45 PM CDT (2245 UTC), as captured by NOAA’s GOES-East satellite. Credits: NASA/NOAA GOES Project.

NASA’s page on Hurricane Harvey has been updated many times, sometimes several times a day, since Harvey began its life as Tropical Depression 9 on 17 August. It includes plenty of satellite imagery of the storm, as well as temperature and rainfall maps.

The Earth at Night, Updated

NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA’s Goddard Space Flight Center.

NASA has released updated global maps of the Earth at night. The so-called “black marble” maps show where human activity lights up the darkness. NASA’s page highlights some of the differences between the 2016 and 2012 versions of the map with before/after interactive sliders. John Nelson has tried something different: overlaying the 2016 map on the 2012 map with a clipping mask shows newly illuminated parts of the globe as dark patches.

John M. Nelson, “A Changing Earth at Night,” 2017.