Satellite imagery surrounds us — from Google Maps and daily weather forecasts to the graphics illustrating news stories — but almost all of it is from a map-like, top-down perspective. This view allows satellite data to be analyzed over time and compared with other sources of data. Unfortunately, it’s also a distorted perspective. Lacking many of the cues we use to interpret the world around us, top-down satellite imagery (often called nadir imagery in remote sensing jargon) appears unnaturally flat. It’s a view that is disconnected from our everyday experience.
If you’re a Planet customer — or you’re just a fan of pictures of Earth from space — you may have noticed some recent changes in our image gallery. In the past few weeks we’ve added dozens of new images featuring everything from tropical glaciers to fjord fog to the impact of the novel coronavirus:
Neil Peart died last week.
I found out on the company Slack, when a good friend and colleague sent me a link to the CBC article announcing his passing, followed by a simple “sigh”.
My reply was an equally succinct four letters, but far less sanguine.
I took a deep breath, flipped off my computer, and headed out into the mild San Francisco winter to think and reflect. But I didn’t bring headphones. I wasn’t ready for that. Not yet.
It is impossible to overstate how important Rush, and Neil’s lyrics, have been to my life. I’ve been listening…
There are only a few dozen sites on Earth that are optimal for rocket launches, and they’re either extremely remote, on the edge of an ocean, or both. There are several good reasons for this, which are all a side effect of the speeds needed to reach orbit — about 28,000 kilometers (17,500 miles) per hour to get Planet’s satellites into orbit 500 kilometers (310 miles) above the Earth’s surface. (That’s 80 times the top speed of a Formula 1 car!)
Reason One: A rocket launch is dangerous. To get off the ground and into orbit it takes a lot…
A year ago, I put together a series of satellite views of 21st Century Landscapes—areas where humans had completely reshaped their environment since the year 2000. The things is, humans are an industrious species, and we just won’t stop building things (or, occasionally, rehabilitating things). Here’s a set of images highlighting the links between development from Antarctica to Sub-Arctica Canada, Shanghai to Midway Island.
Each image was collected by one of Planet Labs’ SkySat high-resolution Earth observation satellites. At full size—2500 by 1406 pixels—each is 0.8 meters per pixel and 2.0 kilometers by 1.1 kilometers (1.2 miles by 0.70 miles), north up, and displayed in true color. All images ©2018 Planet Labs, Inc. CC BY-SA 4.0.
While it’s possible for hand-made data visualization to be distorted (hopefully with intention) it’s not inherent to the medium—precise, meticulously drawn maps, charts, and graphs are quite doable, and were the norm before the arrival of computer-aided-design and drafting and R.
From Melbourne, Australia to Abu Dhabi, United Arab Emirates; Formula 1 is a truly global sporting event. Over the course of a 10-month-season and 21 Grand Prix, each car will race more than 3,360 kilometers (plus additional distance during testing, practice, and qualifying).
After writing an article on handcrafted data visualization a few months ago, I kept my eyes open for new examples. As they accumulated, I began to notice a few commonalities that displayed the power of graphics created by hand: distortion, precision, physicality, and art.
I’ll start with a painting (above) of Yosemite National Park. Here’s the Government Publishing Office’s description: “Looking down Yosemite Valley from west to east, an alpine panoramist depicts the Yosemite National Park’s wondrous rock forms, hanging valleys, waterfalls, lakes, and streams with El Capitain and Half Dome forming the central spectacle with Bridalveil and Yosemite Falls.”
After color correction, there’s a few more image processing steps that can really help a satellite image stand out from a crowd—boosting saturation, local contrast enhancement, and sharpening fine details. These are partly physically-based (accounting for how the atmosphere, optics, sensor, and data processing effect an image)—and partly aesthetic (purely for making an image appealing). Fortunately, these processes can be easily achieved in GIMP or other image editing software with a saturation adjustment, an unsharp mask with a wide radius and low amount, followed by another unsharp mask with a small radius and a large amount.
Now that you’ve found and downloaded satellite data of an area that interests you—or just the sample datasets I pointed to in the Accessing Data and Pre-processing Multi-band Data for Sentinel-2, or Stitching Data for SkySat—what next? How can you convert raw numbers into a picture that evokes the feeling of looking down at Earth from space?
At a global scale, it’s essential to process satellite data automatically—there’s just not enough time to work on images individually. Instead, the data is processed by algorithms (not unlike the software in a digital camera) to convert from bits to pixels.
Data Visualization, Planet Labs. Ex-NASA. Blue Marble, Earth at Night, color.