NDVI (Normalized Difference Vegetation Index)

What can NDVI drones do for my business?
Misconceptions and advice from agriculture industry experts
There’s a lot of hype about agriculture drones. By AUVSI’s own estimates, the U.S. drone industry will be worth $82 billion by 2025, with agriculture generating the lion’s share. Source: auvsi.org/econreport
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What is NDVI to you?
NDVI is not a new formula by any means. It’s been available to farmers from satellites as an entry-level aerial perspective for a while. It has been very easy to get into and produce. I think that’s why it’s been so widely used.

What is the value of NDVI?
Where we see value is variability. There is always variability in all fields. NDVI highlights this variability and makes it easier for your eyes to see. When you can easily see variability, you can make quicker decisions.

What are some of the challenges with using NDVI?
One of the challenges with using NDVI is that you’re not always dealing with absolute values. When lighting conditions and cloud cover change, the camera lens gives you a value of what it sees but doesn’t account for the atmospheric change. If you fly over the same fields on different days with the same camera, you should get the same values… but you don’t. You’ll get the same variability but you won’t get the same numbers on the NDVI scale.
Because of this, it is extremely important to put your boots on the ground — every NDVI map should still be ground-truthed.

The power right now is in understanding your own field. Truly understanding it. Soil type, history — all of it.

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What is your experience with NDVI?
NDVI has been around for a long time. Drones are a bit newer. Just three years ago we were so focused on putting a drone in the air and getting this NDVI image. It was all that mattered. Stick a modified GoPro on the drone, send it on up, and create the best image ever!
After flying, it took 15–20 hours to process the data. That’s what we did back then. These days it’s easier. We want to see the inconsistencies in our fields.
What are some misconceptions about NDVI?
I don’t care what NIR camera you’re using — it takes no account for the soil, the fertility, or other problems in the field. It’s just basing the decision off of the vegetation algorithm and imagery from that day. It’s not necessarily the holy grail. NDVI maps do not replace an agronomist in the field.
Are yield estimations valuable to a grower?
Not as much as you’d think. Guessing yield is not a critical or unknown component to a farmer. Growers have known how to do that their whole lives. They can take a small section of field, make a quick count, and extrapolate that across the entirety for an accurate estimation.

So what do growers want to know?
They want to know if they have problems on this 160 acre field today or can they move on to the next field and continue their daily routine. The immediacy of the data is what can make a big difference. False NDVI imagery from RGB cameras can even be valuable if they highlight inconsistency — it can be a huge time saver to quickly detect variance and then go to the spot and make a decision.