Aerial NDVI imagery has been widely used to assess crop vigor across a field, areas of ponding and changes in field conditions over time.
Normalized Difference Vegetative Index (NDVI): is a calculated index used to monitor crop health and photosynthetic activity. The higher the index value the greater the crop vigor. A color gradient is applied to make the image easier to interpret. We use a gradient of red to green; red being the low values and green being the high. We use four colors with each color representing approximately 25% of the field. This is similar to how a yield map represents data.
The NDVI images are used to examine the differences among plants that absorb different levels of red wavelengths of light. The leaves of healthy growing vines reflect a low level of red wavelengths, and will generate a higher value on the NDVI scale. Dormant or unhealthy vines will appear as low values on the NDVI scale.