Drone Scouting
Our drone is capable of imaging up to 750 acres/day, and in most cases, we can get imagery in farmers’ hands within 24-48 hours. For each field flown, we provide both orthomosaics and several different vegetative indices. Examples of this imagery is provided on the accompanying tabs.
An orthomosaic takes numerous aerial images and assembles them into a single image. The resulting image has high definition and is georeference, meaning that it can be analyzed in GIS software. Orthomosaics are useful for identifying problems that can be observed with the naked eye, such as wind or hail damage, water damage, some late stage crop diseases (e.g. Anthracnose Stalk Rot), and severe nutrient deficiencies. The orthomosaic allows one to pinpoint and to assess the extent of the aforementioned problems
The orthomosaic below was taken in February. You can clearly see which acres were bean ground the previous year and which were corn acres. Note that the resolution of the image below was reduced for viewing on the internet. The actual image has about 10 times the resolution of what you see below.
Normalized Difference Vegetative Index (NDVI)
NDVI is the standard vegetative index in agriculture. It compares the amount of red light (λ ≅ 660 nm) emitted to the amount of near infrared light (λ ≅ 790 nm) emitted. The index provides a general measure of vegetative health. It ranges from -1 to 1, where higher scores indicate healthier crops.
Enhanced Vegetative Index (EVI)
The EVI is similar to the NDVI. Both indicate crop health and both use data from red (λ ≅ 660 nm) and near infrared (λ ≅ 790 nm) wavelengths. The formula for the EVI is slightly different because it tries to adjust for some problems with the NDVI, which is less reliable in the presence of certain atmospheric conditions and when soil is visible through the canopy. The NDVI can also become saturated when a plant canopy is dense.
We primarily rely on the EVI late in the growing season when the crop canopy is dense and NDVI images tend to show little variation. EVI images will still pick up variation in crop health and allow us to visualize disease pressure and/or nutrient deficiencies well into the reproductive stage of corn and soybean growth.
Normalized Difference Red Edge (NDRE)
NDRE images use light emitted from the red edge (λ ≅ 735 nm) and near infrared (λ ≅ 790 nm) wavelengths. Light from the red edge region of the light spectrum falls between the red and near infrared wavelengths. This region marks the boundary between light being absorbed by chlorophyll at red wavelengths and light being scattered at infrared wavelengths. As a result, it is much more sensitive to fluctuations the level of leaf chlorophyll than NDVI.
NDRE images are useful for identifying crop diseases and insect infestations. They are also a rough indicator of the nitrogen content in the leaves and can be used to diagnose crop health problems caused by nitrogen deficiencies. NDRE images are particularly useful as corn and soybean fields enter the reproductive stage because, like EVI, the NDRE is more sensitive to subtle changes in chorophyll levels than NDVI.
Green Normalized Difference Vegetative Index (GNDVI)
GNDVI images differ from NDVI in that they utilize the amount of green light (λ ≅ 550 nm) emitted instead of the amount of red light (λ ≅ 660 nm) emitted. GNDVI indicates the greenness of the plant or the amount of photosynthetic activity. GNDVI is an indicator of the leaf area and indicates both water and nitrogen uptake by the plant. As such, it is useful as an indicator of water stress and also can be used as an indicator of some nutrient deficiencies.
