Odds & Ends: Rabaul Volcano Erupts (in 1999)

September 19th, 2011 by Robert Simmon

Once upon a time Landsat images were expensive (Landsat 7 data was $600 per scene, and the earlier satellites were even pricier) and difficult to find. Now the data—which dates to 1972—is free, and reasonably easy (or at least not painfully difficult) to browse and download from the Global Visualization Viewer, or even the Google Earth Engine (which still has some rough edges).

There are some amazing things buried in the archive, like this natural-color image of an eruption at Rabaul. According to the Global Volcanism Program the activity at the time was “continuous, forceful emissions of thick, light-to-dark gray ash clouds.”

Poke around, and let me know what you find.

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Another ISS Timelapse, from Algeria to Ukraine

September 16th, 2011 by Robert Simmon

 

The photos were taken about 3 seconds apart, from 11:20 to 11:31 UTC, September 3, 2011. Images from the Gateway to Astronaut Photography of Earth.

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A Muddy Chesapeake Bay

September 16th, 2011 by Robert Simmon

Callan Bentley of Mountain Beltway posted a photo of the Chesapeake that’s a nice complement to the view from space we published last night. I live in the Anacostia River watershed, which feeds into the Chesapeake, and all the nearby streams have been brown since Hurricane Irene hit three weeks ago. The Bay is probably going to be muddy for a while.

You can see how things progress with twice-daily satellite views of the Bay via the image “subset” centered on the Chesapeake Lighthouse. Unfortunately, it’s been cloudy the past few days, but there’s a chance there will be a clear shot by early next week—the forecast for Monday is “mostly sunny.”

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Odds and Ends: Nabro Volcano and Texas Wildifres

September 15th, 2011 by Robert Simmon

 

Two more images that don’t quite fit on the main site: Nabro Volcano and the Riley Road Fire near Houston.

Nabro Volcano

This long-dormant Eritrean volcano began erupting in June, but it’s so remote (at least for western media and scientists) that there’s been no news from the area for months. Unfortunately it’s often been cloudy, so we haven’t gotten any good satellite imagery, either. The best recent imagery is this false-color image (vegetation is red), which shows activity has ceased, although there may be a slight hint of gas emissions near the vent. We’re still trying for better imagery, and will post anything we get in our Volcanoes and Earthquakes section.
 

Riley Road Fire

Closer to NASA’s home is this photograph from last week of smoke from the Riley Road Fire, which burned 18,960 acres (7,670 hectares) near Houston, Texas (visible in the upper right corner). It was taken by an astronaut aboard the International Space Station, who could probably see his (the Expedition 28 crew is all male) house at the time.

Credit for the Nabro Volcano image goes to the the NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team, and credit for the Riley Road Fire to the Image Science and Analysis Laboratory, NASA-Johnson Space Center.
 

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Time Lapse from the ISS: Africa to Mongolia

September 14th, 2011 by Robert Simmon

A time-lapse sequence from the International Space Station taken on September 3, 2011. The station starts above Northern Africa, then passes over the Mediterranean Sea and Turkey, followed by the Black and Caspian Seas, the Great Steppe, and finally Mongolia and Lake Baikal.

For more ISS (and Shuttle, Apollo, etc.) photos, check out The Gateway to Astronaut Photography of Earth.

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Planetary-scale Landscaping

September 14th, 2011 by Robert Simmon

Sometimes I’ll find a surprise in a satellite image. In this case, kilometer-tall letters that spell out “LUECKE” near Austin, TX (Near the Bastrop Fire):

Although this could have just been a curiosity for passing pilots and astronauts, it turns out that Johnson Space Center scientists used the letters to estimate the maximum resolution of cameras aboard the Space Shuttle.

We also made an empirical estimate of spatial resolution for lower contrast vegetation boundaries. By clearing forest so that a pattern would be visible to landing aircraft, a landowner outside Austin, Texas (see also aerial photo in Lisheron 2000), created a target that is also useful for evaluating spatial resolution of astronaut photographs. The forest was selectively cleared in order to spell the landowner’s name ‘LUECKE’ with the remaining trees (figure 10). According to local surveyors who planned the clearing, the plan was to create letters that were 3100 ´ 1700 ft (944.9 ´ 518.2 m). Photographed at a high altitude relative to most Shuttle missions (543 km) with a 250-mm lens, Formula 3 predicts that each pixel would represent an area 28.6 ´ 36.0 m on the ground (table 5). When original film was digitised at 2400 ppi (10.6 mm/pixel), letters correspond to 29.4 ´ 18.8 pixels for a comparable pixel size of 27 – 32 m.

It’s reminiscent of the map of Italy I saw on a hillside near Castellucio, in the Apennines, or even the Nazca Lines. What other examples of landscaping visible from space are out there?

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Why I love Geologists

August 30th, 2011 by Robert Simmon

Of all the Earth sciences, geology has the strongest tradition of visual communication. It’s probably because mapping is fundamental to the field, and geologists have 200 years of practice at it. As a result, they tend to create well designed imagery.

Two exemplary techniques geologists use: they almost always include a scale, and they often annotate images directly, rather than relying on separate keys or text descriptions. Here’s an example from Lockwood DeWitt, of Outside the Interzone:

Callan Bentley, author of Mountain Beltway, added annotations that show small faults, and the distribution of grain size in the rock:

Callan even used different colors to differentiate types of information, and varied the size labels to emphasize the location and type of faulting. Excellent work.

Here’s what Lockwood had to say about Table Rock:

Table Rock is quite similar to the more widely known Fort Rock, but larger and better preserved. It erupted enough material that toward the end, it had raised a cone above the original water-influenced explosive (hydrophreatic) vent. The final phase was a more gentle effusive basalt eruption, which filled in the hollow interior. Without that basalt filling, Table Rock would look very similar indeed to Fort Rock. Here’s the location in FlashEarth, maybe a hundred yards north of the dirt road. The two features both lie in the Fort Rock-Christmas Valley, which were filled by a pluvial lake during the Pleistocene. Even a quick glance over this area reveals quite a few similar water-mediated eruptions. In this view, Hole-in-the-Ground is in the left of the top middle, Fort Rock is in the upper middle, just to left of the four center-pivot irrigation fields, turning the rotated “L” into a backwards “C,” and Table Rock is in the bottom right middle, just above and a bit to the right of the Highway 31 label and tight cluster of irrigated fields.

By the way, I don’t include a scale in every image. Sometimes I just want to let the beauty of a spot be what it is. so I take two pictures. One with, and one without, scale. Here’s an example from a couple days earlier, sans scale. But I have a number of other photos of the same spot (not posted yet) that do provide a sense of scale.

I rest my case.

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Visualization Secrets

August 22nd, 2011 by Robert Simmon

“… complex datasets require complex visualizations. In general though, simpler is usually the best way to go in the sense that you should make it as easy as possible for a reader to understand what’s going on. You’re the storyteller, so it’s your job to tell them what’s interesting.”

—Nathan Yau, author of Visualize This: The Flowing Data Guide to Design, Visualization, and Statistics and the Flowing Data blog (that I should read more frequently). Found on SmartPlanet.

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See Something or Say Something: Washington, DC

August 8th, 2011 by Robert Simmon

Every visualization blog on the planet has already posted one or two of these, but they’re awesome, so here is what Washington, DC looks like via Tweets (blue) and photos posted to Flickr (orange). White areas have both tweets and photos.

Unsurprisingly, tourist areas are dominated by photos, residential areas by tweets. More here: See something or say something. Visualization by Eric Fischer. H/T to Visual Complexity.

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Spatial Humanities

July 26th, 2011 by Robert Simmon

There’s an interesting article in today’s New York Times about mapping historical landscapes: Digital Maps Are Giving Scholars the Historical Lay of the Land.

Few battles in history have been more scrutinized than Gettysburg’s three blood-soaked days in July 1863, the turning point in the Civil War. Still, there were questions that all the diaries, official reports and correspondence couldn’t answer precisely. What, for example, could Gen. Robert E. Lee actually see when he issued a series of fateful orders that turned the tide against the Confederate Army nearly 150 years ago?

Now historians have a new tool that can help. Advanced technology similar to Google Earth, MapQuest and the GPS systems used in millions of cars has made it possible to recreate a vanished landscape. This new generation of digital maps has given rise to an academic field known as spatial humanities.

Along with some nice examples.

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