This is an NDVI of pastures created using a modified Canon S100 NIR camera. Is there such a thing as a “sweet spot” for the NDVI rendering? If I slide in from the low side (0.3) the newly cropped fields get redder. If I slide in from the high side (0.71) the cover crops get much darker green. But are either of these changes of any actual value? Do they result in more meaningful data? Is there a reason to do either?
Great question.
This doesn’t change the NDVI values, but rather changes how they are colored. NDVI is a normalized index, so it’s only relative to the existing map, and is a relative measure (you can tell whether something is better or worse than something else), but aside from that, unless you’re using a much fancier sensor with calibration plates etc. the specific number doesn’t have much meaning.
Changing the colors is helpful to give you a better visual understanding/interpretation of where some areas are better/worse, and being able to remove things which are way too high (surrounding trees) or too low (roads) in order to focus the variance on the intended crops.