Dynamic and Standard Vigor
All Vigor (or NDVI) images are black and white pictures that display data collected by the camera with values ranging from 0 to 1. With our Vigor layer tools, you are able to see these pixels of numerical data displayed in color, creating an detailed illustration that indicates general plant health.
Below is an NDVI image in grayscale with a corresponding histogram.
TerrAvion then applies a color-map, such as the one below, to this NDVI data.
Selecting the Standard Vigor layer will apply a fixed color map that stays constant from week to week. The Standard Vigor map is a great tool for observing temporal changes from week to week throughout the season.
Selecting the Dynamic Vigor tool will apply a color-map that automatically adjusts to focus only on the range of NDVI present for any field a a particular date. The Dynamic Vigor too is great for bringing out a lot of detail of a specific image.
In the example below, the Standard vigor levels on the histogram increase from April to August and then drop down in September before harvest.
While the standard vigor map does a good job of telling the story about what happened over the course of the whole season, you’ll notice the field doesn’t show much variation at the beginning and end.
This Standard Vigor map doesn't show all of the early season growth across the field (see image below of Standard Vigor map),
But the Dynamic Vigor map highlights any early-season variation (see image below of Dynamic Vigor map).
If you wanted to check out the best and worst part of the field after this mid-June delivery, you’d have a hard time knowing where to go using the standard vigor map (see below).
This Dynamic Vigor image makes it easy to see variation (see below).
If you’re looking for early-season variation, visiting the field in June, or trying to watch the crop dry down before harvest, you want to see the most amount of variation across the field at any time.
The Dynamic vigor image displays the full range of color across the field--so the lowest vigor part of the field always looks low and the highest vigor are of the field is always high--regardless of whether the crop is doing well or not.
When should I use Standard Vigor vs Dynamic vigor?
Use Standard Vigor when you want to see the actual progress of the field--e.g. to compare many fields in an area to each other--or to compare a field from one season to the next.
In this example (where pink is high vigor) the bottom-middle field appears to be doing the best, while the top-left field has a lot of issues.
Use Dynamic Vigor when you want to see maximum variation across the field at any time of year--and to identify the strongest and weakest areas of the field.
Don’t use Standard vigor to get a sense of whether a field is doing well or not.
In this Dynamic Vigor example, the vigor scale is adjusted to the highest vigor field. Although it brings out a lot of variation in the high vigor field (that you couldn’t see in the regular vigor map) it makes the other fields look much worse than they actually are.
Here’s the same group of fields, but with the lowest vigor field selected using Dynamic vigor. If you were trying to get a sense of the progress of any particular field, Dynamic vigor isn’t going to help very much.