What does an NDVI value closer to -1 signify?

An NDVI value closer to -1 indicates the presence of features such as water bodies, bare soil, or rocks. The Normalized Difference Vegetation Index (NDVI) is a widely used remote sensing measurement that differentiates vegetation from non-vegetated surfaces.

Values of NDVI range from -1 to +1, where positive values indicate increasing amounts of healthy vegetation. Values near zero typically correspond to areas with sparse vegetation or urban environments. Consequently, negative values, particularly those approaching -1, are associated with surfaces that do not support vegetation, such as water or exposed rocks. This relationship is critical in remote sensing applications to identify and classify land cover types effectively.