Why does truth matter in satellite imagery?

Last December, my 14-year-old daughter made a frantic call to her IT support person: me. “Dad,” she shouted, “I need help with my computer!” She makes these calls regularly, since (like most of us) there’s always something about technology—hardware, software, network, device interoperability—that she finds totally frustrating.

“What’s the matter, ma’am?” I asked in my finest Best Buy Blue Shirt voice. “It’s these messed up pictures,” she replied. “They look fine on my phone, but when I try to use them in my Photobook app they look all grainy. How do I make them look clearer?”

I stood there quietly, shaking my head in disbelief. One of the recurring subjects of my work life—the number of pixels you need to capture to produce very high quality imagery—had followed me home.

Not long before my daughter’s question, DigitalGlobe founder Walter Scott published a blog post about the limitations of trying to improve satellite image resolution well beyond its native collected resolution using software. Dr. Scott’s article is an important attempt to set the record straight, since a quick search of the internet reveals a distinct lack of understanding. This confusion exists in part because the market fails to distinguish between product quality and collection quality—making a true understanding of satellite imagery properties like resolution and accuracy difficult for most users.

The current state of affairs is documented by a multitude of professional and academics sources. For example, the American Society of Photogrammetry and Remote Sensing notes in its ASPRS Accuracy Standards for Digital Geospatial Data that “currently, there is no consistent and appropriate accuracy standard that applies specifically to new technologies for digital geospatial data.” ASPRS goes on to say that “collection Ground Sample Distance (GSD), display GSD, and product GSD, from the same source digital imagery, can be very different.”

Over the past few years, we have seen a growing trend in the satellite imagery market that attempts to capitalize on this confusion. New products are offered with product resolutions that far exceed the capabilities of their collection resolution. We also see new products that focus specifically on maximizing resolution at the expense of their product accuracy. These claims impact the industry as a whole by making customers question the value they’re receiving for their investment in satellite imagery.

In response to these exaggerated claims from others in the industry about improving native data quality using software, DigitalGlobe is establishing a new quality standard to give the market absolute confidence in the resolution of the products they purchase from us. We are calling this quality standard “True.” It applies to our best-in-class 30 cm imagery—now known as True30—as well as our 50 cm products—now called True50.

What does “True” mean for a DigitalGlobe product? It means that the product resolution and product accuracy will always be fulfilled by an image with a similar or better collection resolution and accuracy. For example, a True50 product will be fulfilled by an image collected at 59 cm or better—it cannot be created from a 60 cm image, a 70 cm image, an 80 cm image and so on. However, a 30 cm image or 40 cm image can be used to create a 50 cm True product, if that’s what a customer’s needs dictate. You can be assured that a True50 product uses only images truly collected in the 50 cm range or better.

True30 and True50 image collection and accuracy standards

Why does “True” matter?  Well, as Dr. Scott said in his blog post, “an image is just like a book, a painting, or a master audio recording. The information that is captured at its creation is all that will be available a day, a month, or a decade later on. So when you hear someone say that a low-quality satellite image can show you the same thing as a high-quality image, feel free to point out that making it bigger doesn’t make it clearer.”

We want to hear from you about your experience with “true” products, and with competing products that have exaggerated their “truthiness.” Send me your thoughts on how the qualities of DigitalGlobe’s True30 or True50 products have saved you time or improved the quality of your image analysis. We will share some of your stories down the road to help all purchasers of satellite imagery maximize their investments.

Meanwhile back at home, my daughter dealt with the news that there was nothing I could do to help her pictures calmly. She simply replied with the familiar lament of teens everywhere: “Dad, I need a new phone.”