# Generated by scripts/sync_indices.py from Awesome Spectral Indices (MIT).
# DO NOT EDIT BY HAND. Edit overlays (_asi_*.yaml, _folia_*.yaml) and re-run.
# Spec: docs/spec/SPECTRAL_INDICES.md
slug: ndmi
name: Normalized Difference Moisture Index
short_name: NDMI
formula: (N - S1)/(N + S1)
bands:
- N
- S1
domain: vegetation
theme: vegetation
concepts:
- soil-moisture
- leaf-area-index
rank: 4
display:
  colormap: brbg
  range:
  - -1.0
  - 1.0
pedagogy:
  description: 'Normalized Difference Moisture Index. Contrasts near-infrared with

    shortwave-infrared band 1 to estimate canopy water content. The

    standard moisture-stress index in operational forest and crop

    monitoring pipelines.

    '
  use_cases:
  - Canopy water-content and equivalent-water-thickness estimation
  - Drought and irrigation-stress detection during the growing season
  - Fuel-moisture proxy in wildfire-risk modelling
  limitations:
  - Confounded by leaf-area changes — falling NDMI may indicate either dehydration or leaf loss
  - Saturates over very dense, well-watered canopies
  - Cannot retrieve water content under cloud, smoke, or thick aerosols
  interpretation:
    high: Wet, well-hydrated canopy
    mid: Typical green canopy
    low: Water-stressed or senescing vegetation
    negative: Bare soil, urban, water
  authoritative_sources:
  - label: Gao 1996
    url: https://doi.org/10.1016/S0034-4257(96)00067-3
  - label: NV5 ENVI — Canopy Water Content
    url: https://www.nv5geospatialsoftware.com/docs/CanopyWaterContent.html
  - label: Index Database · NDMI
    url: https://www.indexdatabase.de/db/i-single.php?id=56
references:
- url: https://doi.org/10.1016/S0034-4257(01)00318-2
date_of_addition: '2021-12-01'
contributor: https://github.com/bpurinton
platforms:
- Sentinel-2
- Landsat-OLI
- Landsat-TM
- Landsat-ETM+
- MODIS
source:
  authority: awesome-spectral-indices
  commit_sha: 7f28d3fe68af1287f7449faf0685659e73197212
  upstream_id: NDMI
match_tags:
- difference
- index
- moisture
- n
- normalized
- s1
- vegetation
status: stable