NDVI
The normalized difference vegetation index from near-infrared and red surface reflectance, the standard measure of how much green vegetation a pixel holds.
Experimental: not yet fully verified. How results are checked
NDVI is 0.6981.
Provenance
- Computed by
- raster.index.ndvi 1.0.0, core 0.1.0
- Model
- NDVI = (NIR - Red) / (NIR + Red) on surface reflectance (Rouse and others 1974)
- Accuracy
- Exact arithmetic on the reflectance given. What the number means depends on the sensor, the atmosphere correction, and the season.
- Notes
- 1 shown with the answer
- Cites
- Rouse, J. W., Haas, R. H., Schell, J. A., and Deering, D. W., NASA, Monitoring vegetation systems in the Great Plains with ERTS
Something look off?
How we got thisFormula, worked example, sources, and proof
Model: NDVI = (NIR - Red) / (NIR + Red) on surface reflectance (Rouse and others 1974)
Accuracy: Exact arithmetic on the reflectance given. What the number means depends on the sensor, the atmosphere correction, and the season.
When to use this: Use this to turn a pixel's near-infrared and red reflectance into the vegetation index nearly every other measure is compared against: checking a value read off an image, sanity-checking a processing chain, or working an example by hand. Healthy dense vegetation runs high because leaves reflect near-infrared strongly and absorb red; bare soil sits near zero and water goes negative.
Limitations: It reads one pixel's reflectance, not an image, and it cannot tell you why a value is what it is: NDVI saturates over dense canopy, responds to soil brightness where cover is sparse, and shifts with atmospheric correction and sun angle. Compare values only within the same sensor and processing level, and use EVI or SAVI where saturation or soil background matters.
Worked example: NDVI. Source: add-spatial-indexing-and-raster imagery-indices scenario: NIR 0.45 and red 0.08 give 0.6981. It is golden test vector v001, and every build checks the tool still gives its answer within its tolerance.
You enter
- Near-infrared reflectance
- 0.45
- Red reflectance
- 0.08
You get
- NDVI
- 0.6981
Review: Not yet independently reviewed by a GIS professional.
Last verified: 2026-09-22, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.
Status: version 1.0.0, core 0.1.0. See this tool in the verification report.
Checked against: 10 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.
Sources
- Monitoring vegetation systems in the Great Plains with ERTS, Rouse, J. W., Haas, R. H., Schell, J. A., and Deering, D. W., NASA, Third ERTS Symposium, NASA SP-351, volume 1, pages 309-317. The normalized difference of the near-infrared and red bands.
Terms
- NDVI: normalized difference vegetation index
- The difference between near-infrared and red reflectance over their sum. Green vegetation reflects near-infrared strongly and absorbs red, so the index rises with leaf cover. Source: Monitoring vegetation systems in the Great Plains with ERTS
Experimental means this tool has not yet met the stable bar: at least 20 golden vectors, differential tests, and an independent worked example.