Likely answer edit

NDVI = (NIR − Red) / (NIR + Red) — ranges from −1 to +1.

NDVI Likely surface
≤ 0.1 Barren rock, sand, snow
0.2 – 0.3 Shrubland, grassland
0.6 – 0.8 Temperate / tropical rainforest
  • Water is typically negative (red reflectance > NIR).
  • Cutoff thresholds vary by region — treat the numbers as ranges, not absolutes.