Instant Volumetric Calculation from a Drone flight: Is it Really that Easy?
This bootstrap study examines the usefulness of volumetric calculation from a drone flight. Is there utility in simplicity?
Sep 5, 2016
One of the coolest, most “gee-whizziest” things I like best about using our trusty ol’ Phantom 3 paired with DroneDeploy is the surface modeling and volumetric calculations. What with all the breathtaking drone-based video out there to view, that may sound kind of odd to some, but over 10 years ago, figuring out volumetric calculations was a difficult enough task that it made for a semester-long project for me in my college days. The thought of acquiring a surface model in less than half a day would have blown the mind of of my past GIS nerd self; not to mention the accessibility of a robotic aircraft to do the study in the first place. Fast-forward back to now, and I’m tinkering out in the oil patch to see if some simple volumetric calculation from a drone and off-the-shelf software is indeed useful
It’s cool and all, but how accurate is the data?
The first question in my mind before even getting off the ground is one of accuracy: Without a survey or ground control points, how correct is the surface models and volumetric calculation from a drone based dataset? DroneDeploy reports the user tests have been found to be within 1-2% of traditional ground-based laser measurements when following their best practices. Other UAS companies such as Event38 Unmanned Systems have produced their own research with that show the use of ground control points improves the accuracy of volumetric calculations in stockpile measurements.
Let’s see for ourselves!
In the spirit of scientific curiosity, I decided to do a “quick and dirty” unscientific experiment to see how close my DroneDeploy volumetric calculations are to a proper control. It figures that the easiest way to compare volumes is to fly, process the data, and compare my measurements to something of known volume. After pondering what I could fly that I know the absolute volume of, the lightbulb went off. Around our slice of paradise in Western Kansas, oil production is just as big a deal as farming; and often where you find a field, you’ll also find an oil well. Each pumpjack pumps to a set of holding tanks, and these tanks have placards displaying their dimensions.
The tank battery I chose to fly had a tank that had a 5 foot radius, and a height of 15 feet. After doing the conversions to yards and calculating volume, the result came out at 43.6 cubic yards.
My volume as measured in DroneDeploy was 40.8 cubic yards, a difference of about 6.8%.
Can we use it on the farm too?
With the bountiful wheat harvest, and soon to be bumper milo and corn harvest, there are bound to be grain stockpiles placed on the ground around the countryside. Flying the stockpiles and measuring volumes can be a quick and easy way to ascertain how many bushels are there. Knowing with some degree of certainty how close your drone flight acquired measurements are to manually acquired measurements can be beneficial and time saving, not to mention safer too.
Unfortunately, the catwalk along the side of the oil tanks skewed my orthomosaic stitch (and subsequent measurements) around the tanks so I can’t fully attest to the accuracy of my experiment. For a follow-up (in the name of science), I’ll likely try to measure a stand-alone tank or a battery without catwalks. Another problem that crept in was one of precision. Reproducing the same measurement result in DroneDeploy is next to impossible; as each time you draw you measurement boundary it yields slightly different calculations. Is there utility in this functionality all the same? For quick estimates and “gut-check” calculations, I’d say certainly so. Some of the promise of unmanned technology has been dismissed as hype over the last few years; however, volumetric calculation is certainly real and certainly shows potential. As is often the case in farm operations, critical decisions must be made without a whole lot of time to sit and study the data; and in those respects, volumetric calculation from a drone could certainly prove to be a useful tool.
Full disclosure: Apis Remote Sensing Systems, owner of AgFlyers.com is a DroneDeploy business partner. That however doesn’t make the technology used in this post any less cool. 🙂 Don’t believe it? Try it for yourself for FREE!
Anyone else doing any field science they’d like to share? Feel free to comment in the forums in the link below!