By collecting field imagery – whether through a satellite, airplane or even drone – farmers can turn data points into decision points. But an image is never just an image. Often, investigating different types of images can lead to even greater insights, according to Dave Swain, manager of precision ag technologies at Southern States Cooperative.
Southern States studied airplane aerial imagery from 4,000 customer acres this past season, Swain says. In particular, they looked at three distinct types of field images, he says.
1. Aerial view. This is a standard Red, Green, Blue (RGB) image; in other words, a “real-time aerial photo.”
2. Near infra-red (NIR). This images shows the heat and reflectiveness of vegetation in the field. Brighter red areas typically indicate more vegetation. This can sometimes signal high weed pressure, not better crop production.
3. Multi-spectral, or normalized difference vegetative index (NDVI). This image is a combination of RGB and NIR images. This type of image shows a field’s vegetative vigor or potential health of the crop.
The goal of collecting multiple image types is to ID the potential limiting factors that are limiting maximum crop yields, Swain says.
“Typical limiting factors that may be identified [from these images] are moisture, nutrients or compaction,” he says. “Most farmers know where the good and bad producing areas are in their fields. We aren’t really telling them something they don’t already know.”
Southern States used airplanes to capture aerial imagery for its customers. Swain says that allowed them to capture images at one meter, one-half meter or one-quarter meter resolution, comparable to what can be collected with UAVs and higher than what is typically captured via satellite (5-meter resolution).
For the “DIY” crowd who prefer their own drone and capture their own multispectral imagery, there are a wealth of YouTube videos such as this one that describe how to convert a regular camera so it can take NIR or NDVI imagery.
Have a question about RGB, NIR or NDVI imagery? Ask for answers on the AgWeb technology discussion boards.