Cameras compatible with DroneDeploy capture three bands of light. Plant Health maps demonstrate the relative health of vegetation within the map by comparing the value of each band.
Healthier vegetation reflects more of certain types of light than unhealthy vegetation. Your DroneDeploy Plant Health map creates a scale to highlight differences within your area of interest.
For more information on the basics behind NDVI Maps, please see NDVI Cameras for Drones
NDVI map options vary according to your DroneDeploy plan
To learn more about which plans include NDVI layers, please see our Pricing page.
Cameras compatible with DroneDeploy capture three bands of light as input. They capture either:
Red, Green, and Blue light OR
Near-Infrared, Green, and Blue light.
Cameras that capture Near Infrared light can apply the following algorithms:
Cameras that capture Red, Green and Blue light apply the VARI algorithm to assess plant health.
The traditional formula for NDVI compares Near Infrared and Blue light. It is great for measuring healthy, green vegetation over a wide range of conditions.
Below is an NDVI map calculated with the standard formula. We'll use this to compare to the other formulas in order to present different aspects of your data.
VARI was designed and tested to work with RGB data rather than near-infrared (NIR) data. It is a measure of "how green" an image is. VARI is not intended as a substitute for a NIR camera, but it is meaningful when working with non-NDVI imagery. The VARI index was developed on measurement of corn and soybean crops in the Midwestern United States.
ENDVI includes a comparison of Green light in addition to NIR, Red, and Blue in order to give a more sensitive result. This isolates the indicators of plant health, and can be used to assess the presence and health of a crop.
Notice the darker reds that create more contrast compared to the above NDVI image.
OSAVI is a variation of SAVI, with a lower calibration factor. Using OSAVI, there is more variation with the soil than with SAVI, but it is also more sensitive to vegetation. In the example below, we see more subtle vegetation differences with OSAVI than with SAVI above. OSAVI would work well in an area with a dense canopy and a wider spectrum of vegetation.
OSAVI is more sensitive to vegetation than SAVI and would work well in denser canopies.
RDVI is similar to SAVI in that it suppresses the effects of soil and sun. Unlike SAVI, however, it does not work as well in sparsely vegetated or dry areas.
VARI is the only DroneDeploy vegetation index that is significant when mapping with RGB cameras. Developed based on measurements of corn and soybeans in Nebraska and wheat in Israel (Gitelson et. al 2002), VARI measures the reflectance of vegetation versus soil.
Please visit our blog post for more information on the differences between VARI and NDVI here.