Normalized Difference Vegetation Index (NDVI)
Definition
A widely used spectral index calculated as (NIR - Red) / (NIR + Red). Values range from -1 to +1; healthy dense vegetation produces high values. Anomalously high or low NDVI patches in a uniform field can indicate disturbed or enriched ground beneath.
- Formula
- (NIR minus Red) divided by (NIR plus Red)
- Value range
- -1 to +1
- High values
- Dense, healthy vegetation
- Forensic use
- Flagging anomalous patches for possible clandestine graves
Common questions
Why would a buried grave show up as an NDVI anomaly?+
Disturbed soil initially suppresses plant growth, then decomposition products can locally enrich the soil and produce a burst of unusually vigorous growth, so an anomalous patch, either depressed or elevated relative to the surrounding field, can flag ground worth ground-truthing.
Is an NDVI anomaly enough on its own to confirm a burial site?+
No, NDVI only flags a candidate area of disturbed or altered vegetation; confirmation still requires ground-penetrating radar, probing, or excavation, since many other causes such as soil type changes or irrigation can also produce an anomaly.
Related terms
- Cadaver Decomposition Island (CDI)
- The localised area of soil and vegetation altered by the decomposition fluids and gases released from a body. A CDI has a...
- Near-Infrared (NIR) Reflectance
- The portion of the electromagnetic spectrum (700-1200 nm) that healthy green vegetation reflects strongly due to the structure of chloroplasts. Stressed, sparse,...
- Nitrophilous Plant
- A plant species that grows preferentially on nitrogen-rich soils. Examples include stinging nettle (Urtica dioica), broad-leaved dock (Rumex obtusifolius), and elder (Sambucus...
- Phytosociology
- The study of plant community composition and its relationship to environmental conditions. In forensic contexts, the plant assemblage over a suspected burial...
- Soil Inversion
- The displacement of soil horizons when ground is dug. Subsoil is brought to the surface and topsoil is buried, disrupting the established...