Surveying
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If you’re assessing your mobile mapping ca- pabilities in terms of megapixels and image quality instead of image value, you’re wast- Are You Paying Too Much for Your Mobile Mapping Imagery?
ing money. Here’s how to change it. How much does a single pixel weigh? In physical terms, a 64-bit pixel is roughly 0.012200703125 kilobytes, and 50 kilobytes weigh about 8,000,000,000 electrons, which is somewhere around two ten-thousandths of a quadrillion of an ounce, thus 0.012200703125*8,000,000,000\50 equals … oh, never mind. The point is: pixels are pretty insignificant … that is, in terms of physical weight. But how much does a single pixel weigh down your business? Likely, a single pixel has no bearing on your business. But we don’t work in terms of single pixels; we work in terms of MEGApixels. Thousands of color pixels all lined up to present an image. In mobile mapping, we are collecting a lot of images with a lot of pixels. During collections, the data footprint grows quickly. For context, I recently collected a 5-mile project, one pass east, one west. It took about 30 minutes, and the image data footprint was 80GB. That’s a lot of pixels. So, knowing that mobile mapping produces a lot of pixels, shouldn’t we scrutinize the quality of those pixels? Of course we should. But let’s scrutinize their quality not in terms of image quality, but image value. How much value does each pixel you produce in the field actually bring to your organization? It’s a rhetorical question. I ask because regardless of the value they bring, you are paying for all of them. You are paying for them in terms of flat cost per pixel. Image sensor cost per pixel. Processing time per pixel. Storage cost per pixel. Transfer cost per pixel. Maybe it would be easier to consider in terms of overhead. How large are your raw datasets in the field? How long does it take to process them? When you store them on a server or share them with a collaborator, how long does the transfer take? How much does storage cost? Backups? What is the impact on your workstation specs for your produc- In mobile mapping, we are usually working with data that is in the realm of “wow that’s a lot of data” – gigabytes or even terabytes of data collected in a short amount of time. But if we are working with that much data, should it not be rich in value? I am talking about focused data. Not focus as in the sharpness of imagery, but focus as in showing us what we want to see and omitting as much useless information as possible. If someone told you that their mobile mapping system had a 100-megapixel panoramic camera on it, would you be impressed? Probably – that’s a lot of pixels. But if they told you that 90 percent of the pixels in any panoramic image they gave you were useless in terms of value, then how would you feel? If you were paying for 100 percent of that data, 100 percent of the processing overhead, 100 percent of the storage, and 100 percent of the transfer times, you would tion fleet (definitely some cost there). The High Cost of Useless Information
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csengineermag.com
September 2022
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