A Quick Guide to Earth Explorer for Landsat 8

May 31st, 2013 by Robert Simmon

The Landsat Data Continuity Mission is now Landsat 8, and that means images are now public (woohoo!). NASA handed control of the satellite to the USGS yesterday (May 30, 2013), and calibrated imagery is available through the Earth Explorer. Unfortunately, the Earth Explorer interface is a bit of a pain, so I’ve put together a guide to make it easier.

First, go to the Earth Explorer site: earthexplorer.usgs.gov

You can search, but not order data, without logging in—so register if you don’t have an account (don’t worry, it’s instant and free), or log in if you do.

First step, register.

The simplest way to select a location is to simply pick a single point on the map. You can define a box or even a polygon, but that makes it more likely you’ll get images with only partial coverage. Navigate to the location you’re interested in, and click to enter the coordinates. You can choose a data range, but right now there are only 3 or 4 scenes for a given spot, so skip it and just click “Data Sets”.

Pick a spot, then click "Data Sets"

On the data sets page, you can search everything from Aerial Imagery to Vegetation Monitoring. Click the “+” symbol next to Landsat Archive, then the first check box that appears: “L8 OLI/TIRS” (which stands for Landsat 8 Operational Land Imager/Thermal Infrared Sensor (creative, no?)). Click “Results” to start a search.

Select Landsat 8, then Results.

After a short wait, you’ll get a list of available images. The thumbnails aren’t big enough to show much, so click on one to see a slightly larger image. Close that window, and click the download icon: a green arrow pointing down towards a hard drive …

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… which doesn’t actually download the data, just provides a list of download options. “LandsatLook” are full-resolution JPEGs, and are a quick way to check image quality (I’d prefer full-resolution browse images without a separate download, but I digress). The Level 1 Product is terrain-corrected, geolocated, calibrated data—a bundle of 16 bit, single-channel GeoTIFFs. Select the “Level 1 Product” radio button, then click “Select Download Option”.

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Done! Oh, wait. Not done. You need to click one more button: “Download”.

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Now you’re done. The data should arrive in your browser’s designated download folder.

Drop a note in the comments section if I’ve skipped a step, or if you have any other questions. Next week I’ll explain what to do with the data once you’ve got it.

Skylab 2 above the Earth's terminator.

This photo of Skylab was taken by the astronauts of Skylab-2 as they left the space station and departed for Earth on June 22, 1973. More photos from all three Skylab missions are archived on NASA’s Gateway to Astronaut Photography of Earth.

To look through the rest of the Skylab collection, select Find Photos > Search > Mission-Roll-Frame from the menu in the upper-left hand corner of the Gateway to Astronaut Photography of Earth home page. Under Missions pick one or more of SL2, SL3, and SL4, then delete the “E” in the Roll field. Finally, hit Run Query at the bottom of the page. On the Database Search Results page, enable the Show thumbnails if they are available checkbox. Click the number in the Frame column to view a screen-sized image. High-res images are downloadable from each Display Record, just click the View link for the image size you want.

Enjoy.

Annular Solar Eclipse: May 10, 2013

May 10th, 2013 by Robert Simmon

Japan’s MTSAT-2 (also known as Himawari-7) collected these images of today’s annular solar eclipse from geostationary orbit. The satellite (similar to the United State’s GOES satellites), observed the moon’s shadow as it passed over Australia & the Pacific Ocean. The image sequence begins at 21:32 UTC, with an additional image each hour until 02:32 UTC. The eclipse itself lasted from 22:33 UTC until 02:20 UTC.

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Visible-light & infrared MTSAT images dating back to October 2006 are available from the Earthquake Research Institute & Institute of Industrial Science, University of Tokyo.

Earth Day and Night

April 22nd, 2013 by Robert Simmon

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Earth Day (8,192 by 8,192 pixels, 9.1 MB JPEG)
Earth Night (8,192 by 8,192 pixels, 4.2 MB JPEG)

Credit: NASA Earth Observatory images by Robert Simmon, using Suomi NPP VIIRS data from Chris Elvidge (NOAA National Geophysical Data Center). Suomi NPP is the result of a partnership between NASA, NOAA, and the Department of Defense.

Is Animation an Effective Tool for Data Visualization?

March 14th, 2013 by Robert Simmon

I (@rsimmon) had a brief exchange this morning about the use of motion graphics in data visualization with Alberto Cairo (@albertocairo) and Andy Kirk (@visualisingdata) which quickly outgrew Twitter’s 140-character limit:

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The increasing use of animation (and 3D) in data and information visualization is definitely a trend, but I don’t think it’s a good one. My (possibly naïve) understanding is that motion in data visualization is great for engagement (nothing can capture the attention of the human visual system like motion), but can be a detriment to comprehension. Cognitive science researchers like Barbara Tversky and Richard Lowe discovered that animations—even “well designed” ones—were often less effective than static diagrams at communicating concepts like the inner workings of a British toilet (I’m not kidding) or the movements of a piano action. Motion may get more people to view a graphic, but they may learn less from it.

Don’t get me wrong: recent work by Graham Roberts (thanks Andy!) and many other designers is stunning, and I love working in compositing and 3D software. One of the best visualizations I’ve ever done—a satellite view of the terminator over the course of a year—is animated:

But animation is typically more difficult and time consuming to produce than static visualization. Even if it’s no worse than a static graphic, is an animation worth the extra expense?

Alberto also touched on the issue of audience: does the general public understand data visualization? On the web that may not be something we have to worry about. Anybody that clicks a link on the Interent is the member of an attentive public—they’re actively seeking information. An attentive person is already interested in a topic, and is usually willing to do the mental work to understand what they’re looking at. (Jon Miller pioneered the concept of attentive publics in his 1983 book, The American People and Science policy: The Role of Public Attitudes in the Policy Process.)

Data visualization is a young field, however, and perhaps we’ll learn how to make beautiful, effective animations quickly & inexpensively. Right now, however, perhaps we should focus on improving more pedestrian information displays.

Art, Aesthetics, Design, And Data at the 2012 Fall AGU

November 29th, 2012 by Robert Simmon

I’ll be speaking at the upcoming Fall AGU in San Francsico Tuesday morning—8:15 a.m. December 4, room 104 Moscone South. PA21B. Communication of Science Through Art: A Raison d’Etre for Interdisciplinary Collaboration I. (I know, it’s early, but Blue Bottle coffee is close to Moscone Center.)

Art, Aesthetics, Design, And Data: Reaching The Public Through Scientific Visualization

The primary challenge in science communication is attracting a broad audience while maintaining technical accuracy. Scientific topics are often and reflexively considered boring, dry, or difficult by non-scientists. One way to overcome this hurdle and gain the public’s attention is through beautiful and striking imagery. Imaging techniques borrowed from art and design can generate interest in technical or abstract concepts.

NASA’s Earth Observatory routinely uses imagery to communicate current Earth science research. Earth Observatory designers collaborate with NASA scientists to produce imagery using the principles of data visualization. Curiously, the popularity of images tends to be inversely correlated with the scientific content. Simple photographs and illustrations tend to be viewed more often, and more widely shared, than maps and graphs. However, maps of tree density and melt on the Greenland ice sheet are among the most popular images published on the Earth Observatory. These graphics share some features both with each other and our most-viewed natural-color images: clear, relatable themes, intuitive color palettes, and a clean aesthetic. These similarities may explain their success, and provide a roadmap for future data-rich visualizations that engage viewers while communicating complex science.

Please stop by. In addition, I’ve spent the past few weeks putting together imagery for a NASA/NOAA press conference Wednesday morning about a new, very cool sensor on the Suomi NPP satellite, and I’ll be on-hand to answer questions afterwards.

Earth at Night
Wednesday, 5 December
10:30 a.m.

A new cloud-free view of the entire Earth at Night, courtesy of a joint NASA-NOAA satellite
program called Suomi NPP, will be unveiled at the press conference. This image is an order of
magnitude more detailed than the wildly popular earlier Earth at Night image, and reveals new
information scientists are using to study meteorology, natural and human-caused fires, fishing
boats, human settlement, urbanization and more. Scientists will discuss the advancements now
possible with these new images and detail a few examples of the features mentioned above – plus
present images of Earth on moonless nights, lit only by “airglow” and starlight, as well as the
vast difference moonlight makes on the Earth’s surface.

Participants:
James Gleason, NASA Suomi NPP project scientist, NASA Goddard, Greenbelt, Maryland, USA;
Christopher Elvidge, lead of the Earth Observation Group, NOAA’s National Geophysical Data Center in Boulder, Colorado, USA;
Steve Miller, senior research scientist and deputy director of the Cooperative Institute for Research in the Atmosphere (CIRA), Colorado State University, Fort Collins, Colorado, USA

Sessions: A54F, IN33C

If you’re interested I’ll be sending out some of my impressions of the meeting via Twitter: @rsimmon hashtag #AGU12
I’d also love to meet any Earth Observatory readers who are attending—I’ll try to hang around after each of these sessions, or you can send a message through the Earth Observatory contact form:

http://earthobservatory.nasa.gov/Contact/

Be sure to pick the “Design Feedback” topic (otherwise it won’t go to me, but to our harried developer), and leave your email address.

Odds & Ends: Batu Tara Volcano Emits a Wispy Plume

June 26th, 2012 by Robert Simmon

Active since 2006, Batu Tara continues to puff away. A thin volcanic plume streams northwest from the cloud-shrouded volcano. The Advanced Land Imager (ALI) aboard the Earth Observing-1 (EO-1) satellite collected this natural-color image on June 21, 2012.

NASA image By Jesse Allen and Robert Simmon using EO-1 ALI data.

I’m giving a talk about the development of the Blue Marble tomorrow at the Information Week Government IT Leadership Forum. In addition to some details of the render, I’ll discuss the history of NASA’s views of the Earth, starting with TIROS-1, continuing through the Apollo Program, interplanetary probes, and the Earth Observing System. If you’re attending and want a copy of the presentation (or are just curious), here it is. If you check the hidden slides you’ll some interesting images I won’t have time to discuss.

Keynote (124 MB)
Powerpoint (124 zip with .ppt file & folder with movies)
PDF (12.5 MB, no movies)

Related Links

The Blue Marble True-color global imagery at 1km Resolution.
My original blog post, Crafting the Blue Marble.
Blue Marble Next Generation.
The Blue Marble Next Generation—A true color Earth dataset including seasonal dynamics from MODIS. (880 kB PDF).
Pictures of Earth by Planetary Spacecraft The Planetary Society.

Tree Biomass Map Featured on Co.DESIGN

February 28th, 2012 by Robert Simmon

Last month it was Science Friday, this month it’s Co.DESIGN: NASA Creates Insanely High-Res Map Of America’s Trees, And Offers A Lesson In Information Design. Tim Maly describes our map of tree biomass in the U.S. (based on an exquisite data set from Woods Hole Research Center), and lets me rant a bit about color palettes and data visualization.

Science Friday Explains the Blue Marble

February 7th, 2012 by Robert Simmon

Last week, Flora Lichtman of Science Friday put together a short video about the views of Earth NASA has produced over the years. She began with the famous Earthrise photo taken by the crew of Apollo 8, then interviewed me and NASA scientist Gene Feldman. We discussed the differences between photographs and data visualizations, and the craftsmanship that went into the 2002 Blue Marble. There’s even an audio clip from the late Carl Sagan, describing the Pale Blue Dot image from Voyager 1. All spurred by global imagery from the new Suomi NPP satellite.

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