Tag Archives: satellites

“A Font Made Entirely of Satellite Imagery of Buildings”

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A new font makes use of depictions of buildings from above:

Benedikt Gross, a data visualization designer, and Joey Lee, a geographer, spend a lot of time looking at satellite imagery. The duo met at MIT’s Senseable City Lab a few years ago and after realizing their mutual enthusiasm for maps—or, more exactly, strange patterns in the Earth’s surface—decided to collaborate on a dataset called The Big Atlas of LA Pools, inspired by the many shapes of pools in Los Angeles.

Gross and Lee are now onto their new project, Aerial Bold. Once completed, it will be the first typeface created from shapes and patterns from the planet’s topology. Whereas The Big Atlas of LA Pools began as a mission to compare pools per capita with other datasets (like neighborhood crime), Aerial Bold was born from a few errant observations. “Basically we spend so much time looking at satellite images, that we realized there are some letters in them,” Gross says. As is often the case with noticing an oddity for the first time, once they saw a few letters, “suddenly letters were all over the place.”…

First, they synthesize satellite imagery and prep it so an algorithm can read it. This involves cranking up the contrast and blocking out distinct shapes in red. Their software can read those blocks of color and extract letters. So far Gross and Lee have scanned images of Germany, Turkey, Paris, Denmark, Switzerland, California, and New York. Gross says that letters made mostly of right angles, like I and H, have shown up most frequently…

Besides creating the promised font out of satellite images, Gross says Aerial Bold could have any number of creative uses for artists. He and Lee have been approached by publishers interested in flipping the typology into a children’s book on the ABCs—something that Gross mentions could live in a digital format. They also want to share their image-detection methods with the public.

As someone who enjoys cities as well as overhead satellite views, this is quite clever. Such a project also produces a font for the covers of all the new books about cities as well as college campus posters about classes and lectures having to do with urban areas or buildings.

Watching metropolitan sprawl from space

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Check out a set of interesting GIFs showing sprawl in metropolitan regions:

A couple things jumped out at him while studying these animations. “It is interesting to see the ‘greening’ of the mid-ring suburbs of the ’70 to the ’90s as the tree canopies matured,” he says. “This is in contrast to the concrete jungles of prewar neighborhoods and the virgin developments of the 21st century.” (Look again at Dallas/Fort Worth for a good example.)

A few other trends he noticed: Some cities, like Chicago and Philadelphia, grow lighter over time, an apparent consequence of newer, white-roofed buildings crowding out older ones with dark roof tiles. And the shrinking of water sources, whether manmade or natural, is a “sad site to behold,” Williams says. “On the other hand, the creation of artificial land in coastal metropolises is increasingly larger in scale (re: Shanghai).”

If one thinks that any sort of sprawl is bad because it takes up more land, leads to deconcentrated regions, necessarily leads to McMansions and more driving, or other reasons, the images of American cities may look bad. But, the animations of American cities show sprawl on a different scale than that of some global cities. The American regions show more filling in between existing settlements, particularly in more established Northaast and Midwest cities. Sunbelt cities may look more like cities in developing countries where cities have simply exploded rather than filled in.

It is also interesting to consider sprawl from this particular vantage point: via satellites. The average suburbanite might consider sprawl at a closer level; the nearby field that disappeared for a housing development, the increase in traffic as new residents add to the local congestion, the notices about cheaper houses on the metropolitan fringe. But, satellite images and maps help remind us of the broader nature of sprawl: if the region is a circle with the city in the middle, expanding sprawl moves out the outer ring of the circle, adding more and more square miles that is only generally bounded by a large body of water (or perhaps another metropolitan region).

Beautiful infrastructure: new image of the US from space at night

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This is worth gaping at for a moment:

United States

Some of the details on how the image was obtained:

These super-high-resolution images, made possible by a new type of infrared sensor on the satellite, were revealed here at the American Geophysical Union conference Dec. 5.

The Visible Infrared Imaging Radiometer Suite has a “day-night band” that can detect natural and man-made light with unprecedented resolution and clarity. It can resolve everything from the nocturnal glow of the atmosphere to the light of a single boat at sea. It can detect auroras, wildfires, the reflection of moon and star light off clouds and ice and the lights alongside highways. The sensor has six times better spatial resolution and 250 times better resolution of lighting levels than anything that came before it.

The VIIRS instrument works by scanning in 22 different wavelength bands. For each pixel, it uses a low-, medium- or high-gain mode to accurately depict the light from each source. Low-light signals are amplified and bright lights are kept from being over-saturated.

This could be an example of infrastructure at its finest. With a quick glance at this photo, you get an idea of the geographic dispersion of the American population. Of course, it could also tell you something about light pollution…

Seeing urban growth from the Landsat satellite system

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Among other things, the Landsat satellites took pictures of big cities over time. Here are images of 11 of these big cities with roughly 30-40 years between each picture. A few thoughts:

1. I find several of the desert city images, such as Dubai and Las Vegas, to be most fascinating.

2. I’ve always liked overhead or satellite pictures of cities as I think it gives a helpful perspective where one can see the big picture rather than just the nearby area.

3. I’ve wondered several times how difficult it might have been for city dwellers who lived before the 19th century to truly adopt or imagine an overhead view of their city. Clearly, it could be done but it is one thing to imagine and another to see it from an airplane (or hot air balloon or dirigible) or really tall building.

4. I would be interested in spending some time with these images to see if there are discernible patterns. I assume the first thing people would notice is the expansion of development but I assume there are some other things in here such as important transportation corridors (highways and trains) and different kinds of development located in different places.

Bonus: here are some pairs/series of images from American locations.

 

Trying to count the people on the streets in Cairo

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This is a problem that occasionally pops up in American marches or rallies: how exactly should one estimate the number of people in the crowd? This has actually been quite controversial at points as certain organizers of rallies have produced larger figures than official government or media estimates. And with the ongoing protests taking place in Cairo, the same question has arisen: just how many Egyptians have taken to the streets in Cairo? There is a more scientific process to this beyond a journalist simply making a guess:

To fact-check varying claims of Cairo crowd sizes, Clark McPhail, a sociologist at the University of Illinois and a veteran crowd counter, started by figuring out the area of Tahrir Square. McPhail used Google Earth’s satellite imagery, taken before the protest, and came up with a maximum area of 380,000 square feet that could hold protesters. He used a technique of area and density pioneered in the 1960s by Herbert A. Jacobs, a former newspaper reporter who later in his career lectured at the University of California, Berkeley, as chronicled in a Time Magazine article noting that “If the crowd is largely coeducational, he adds, it is conceivable that people might press closer together just for the fun of it.”

Such calculations of capacity say more about the size of potential gathering places than they do about the intensity of the political movements giving rise to the rallies. A government that wants to limit reported crowd sizes could cut off access to its cities’ biggest open areas.

From what I have read in the past on this topic, this is the common approach: calculate how much space is available to protesters or marchers, calculate how much space an individual needs, and then look at photos to see how much of that total space is used. The estimates can then vary quite a bit depending on how much space it is estimated each person wants or needs. These days, the quest to count is aided by better photographs and satellite images:

That is because to ensure an accurate count, some computerized systems require multiple cameras, to get high-resolution images of many parts of the crowd, in case density varies. “I don’t know of real technological solutions for this problem,” said Nuno Vasconcelos, associate professor of electrical and computer engineering at the University of California, San Diego. “You will have to go with the ‘photograph and ruler’ gurus right now. Interestingly, this stuff seems to be mostly of interest to journalists. The funding agencies for example, don’t seem to think that this problem is very important. For example, our project is more or less on stand-by right now, for lack of funding.”

Without any such camera setup, many have turned to some of the companies that collect terrestrial images using satellites, but these companies have collected images mostly before and after the peak of protests this week. “GeoEye and its regional affiliate e-GEOS tasked its GeoEye-1 satellite on Jan. 29, 2011 to collect half-meter resolution imagery showing central Cairo, Egypt,” GeoEye’s senior vice president of marketing, Tony Frazier, said in a written statement. “We provided the imagery to several customers, including Google Earth. GeoEye normally relies on our partners to provide their expert analysis of our imagery, such as counting the number of people in these protests.” This image was taken before the big midweek protests. DigitalGlobe, another satellite-imagery company, also didn’t capture images of the protests, according to a spokeswoman, but did take images later in the week.

Because these images are difficult to come by in Egypt, it is then difficult to make an estimate. As the article notes, this is why you will get vague estimates for crowd sizes in news stories like “thousands” or “tens of thousands.”

Since this is a problem that does come up now and then, can’t someone put together a better method for making crowd estimates? If certain kinds of images could be obtained, it seems like an algorithm could be developed that would scan the image and somehow differentiate between people.