Starting this morning, DigitalGlobe has new permission from the government to sell satellite imagery at 40 cm (16 inch) resolution, up from 50 cm (20 inches). The limit will drop further to 25 cm (10 inches) later this summer, once they’ve launched WorldView-3, which will be the first private satellite technically capable of that resolution. The numbers don’t tell the story, though—let’s look at some pictures.
If going from 50 cm resolution to 40 cm resolution sounds like a small change at first, remember that we’re talking about square pixels. When square A is only ¼ longer on a side than square B, it contains more than 150% as much area. Therefore, a slightly smaller linear size means a lot more clarity. I’ve taken some aerial imagery of San Francisco’s Golden Gate Park and resampled it to demonstrate:
This is 50 cm imagery, the standard as of yesterday. We’re looking at the California Academy of Sciences building at right, with its distinctive green roof.
And here’s 40 cm imagery. With more than half again as much information, we’ve gone from seeing the crowd in front of the museum to seeing their shirt colors. Individual shrubs start to appear, and we can read more road markings—a classic index of sharpness.
This is great news for everyone who uses satellite imagery, but I’d like to highlight two particular points. One is that this shows the US government is shifting out of its post–Cold War mindset of strictly controlling access to commercial imagery. If tight resolution limits made sense two decades ago, they don’t anymore, and regulators are changing with the times. The second is that this isn’t just about San Francisco, NYC, Paris, and other metropolises. Many of them already have satisfactory aerial imagery. This is about having ultra-high-res imagery, and especially series of ultra-high-res imagery over time, of anywhere in the world.
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