VELSTROM LogoVELSTROMPLATFORM
Geospatial Intelligence

PlanetaryIndex Library

Under Development

Comprehensive reference catalog of standard multi-spectral indices computed across satellite channels. Search, filter, and review mathematical definitions.

NDVI

Normalized Difference Vegetation Index

NIRRed

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference Vegetation Index (NDVI)

NDVI = \frac{NIR - Red}{NIR + Red}

Interpretation

Values range from -1.0 to 1.0. Water usually exhibits negative values. Bare soil displays low positive values (0.1 - 0.2), while dense vegetation displays high values (0.6 - 0.9).

Applications

  • Vegetation density mapping
  • Agricultural crop health monitoring
  • Deforestation studies

Limitations

  • Saturates in high-density canopy forests
  • Sensitive to background soil brightness anomalies
EVI

Enhanced Vegetation Index

NIRRedBlue

MATHEMATICAL EXPRESSION

Equation for calculating the Enhanced Vegetation Index (EVI)

EVI = 2.5 \times \frac{NIR - Red}{NIR + 6 \times Red - 7.5 \times Blue + 1}

Interpretation

Values range from -1.0 to 1.0. Resolves canopy background noise and atmospheric scattering, maintaining sensitivity in high-biomass regions.

Applications

  • High-density tropical forest biomass estimates
  • Precision crop monitoring
  • Leaf Area Index (LAI) proxies

Limitations

  • Requires blue band, which is susceptible to aerosol noise
  • More complex computational inputs
SAVI

Soil Adjusted Vegetation Index

NIRRedSoil Factor L

MATHEMATICAL EXPRESSION

Equation for calculating the Soil Adjusted Vegetation Index (SAVI)

SAVI = \frac{NIR - Red}{NIR + Red + L} \times (1 + L)

Interpretation

Values range from -1.0 to 1.0. Employs a soil adjustment factor (L) to correct for background soil reflectance. Usually, L = 0.5 is used.

Applications

  • Arid and semi-arid vegetation monitoring
  • Sparse crop fields health metrics
  • Desert boundary monitoring

Limitations

  • Requires manual estimation or calibration of L factor
  • Does not correct for atmospheric scattering
OSAVI

Optimized Soil Adjusted Vegetation Index

NIRRed

MATHEMATICAL EXPRESSION

Equation for calculating the Optimized Soil Adjusted Vegetation Index (OSAVI)

OSAVI = \frac{NIR - Red}{NIR + Red + 0.16}

Interpretation

Simplified SAVI iteration where L is fixed at 0.16 to optimize vegetation sensitivity in low canopy environments.

Applications

  • Agricultural seeding growth tracking
  • Sparse grassland coverage assessments
  • Soil reflectance correction workflows

Limitations

  • Saturates faster than EVI in high-biomass forests
MSAVI2

Modified Soil Adjusted Vegetation Index 2

NIRRed

MATHEMATICAL EXPRESSION

Equation for calculating the Modified Soil Adjusted Vegetation Index 2 (MSAVI2)

MSAVI2 = \frac{2 \times NIR + 1 - \sqrt{(2 \times NIR + 1)^2 - 8 \times (NIR - Red)}}{2}

Interpretation

Eliminates the manual L factor requirement by using an inductive variable calculation based on NIR reflectance.

Applications

  • Erosion-prone bare soil transitions
  • Sparse desert scrub classification
  • Early stage crop growth tracking

Limitations

  • Computationally intensive quadratic formula calculations
NDWI

Normalized Difference Water Index (McFeeters)

GreenNIR

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference Water Index (McFeeters) (NDWI)

NDWI = \frac{Green - NIR}{Green + NIR}

Interpretation

Values range from -1.0 to 1.0. Positive values indicate open water surfaces, while soil and vegetation present negative values.

Applications

  • Open water body delineation
  • Flooding and inundation tracking
  • Coastal shoreline boundaries mapping

Limitations

  • Sensitive to urban built-up noise, which can result in false positives
NDWI_Gao

Normalized Difference Water Index (Gao)

NIRSWIR

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference Water Index (Gao) (NDWI_Gao)

NDWI_{Gao} = \frac{NIR - SWIR}{NIR + SWIR}

Interpretation

Senses liquid water thickness in vegetation canopy. High positive values indicate healthy moisture status.

Applications

  • Canopy water content monitoring
  • Forest fire fuel dry-state analysis
  • Agricultural drought monitoring

Limitations

  • Cannot delineate open water bodies as effectively as McFeeters NDWI
MNDWI

Modified Normalized Difference Water Index

GreenSWIR

MATHEMATICAL EXPRESSION

Equation for calculating the Modified Normalized Difference Water Index (MNDWI)

MNDWI = \frac{Green - SWIR}{Green + SWIR}

Interpretation

Replaces NIR with SWIR to suppress built-up noise. Open water displays high positive values.

Applications

  • Urban water body extraction
  • Urban flood mapping
  • Glacial lake monitoring

Limitations

  • Requires SWIR bands, which have lower resolution on some satellites (e.g. 20m on Sentinel-2)
NDCI

Normalized Difference Chlorophyll Index

RedEdge1Red

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference Chlorophyll Index (NDCI)

NDCI = \frac{RedEdge1 - Red}{RedEdge1 + Red}

Interpretation

Calculates chlorophyll-a concentration in turbid waters. Higher positive values indicate algal blooms.

Applications

  • Water quality assessments
  • Algal bloom tracking
  • Estuary chlorophyll density

Limitations

  • Requires narrow band Red Edge sensors (like Sentinel-2)
NBR

Normalized Burn Ratio

NIRSWIR2

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Burn Ratio (NBR)

NBR = \frac{NIR - SWIR2}{NIR + SWIR2}

Interpretation

High positive values indicate healthy vegetation. Negative or low values indicate burned forest tracts.

Applications

  • Active forest fire scar delineation
  • Post-fire burn severity indexing
  • Forest fire recovery monitoring

Limitations

  • Can confuse dry soils or harvested crop fields with burn scars
NBR2

Normalized Burn Ratio 2

SWIR1SWIR2

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Burn Ratio 2 (NBR2)

NBR2 = \frac{SWIR1 - SWIR2}{SWIR1 + SWIR2}

Interpretation

Replaces NIR to focus strictly on soil and wood moisture post-fire, eliminating regrowth noise.

Applications

  • Long-term post-fire recovery
  • Agricultural slash-and-burn audits

Limitations

  • Low sensitivity in high-moisture swamp wetlands
NDRE

Normalized Difference Red Edge Index

NIRRedEdge1

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference Red Edge Index (NDRE)

NDRE = \frac{NIR - RedEdge1}{NIR + RedEdge1}

Interpretation

Similar to NDVI but replaces Red with Red Edge 1 to assess crop health in advanced growth stages.

Applications

  • Late-stage agricultural yield predictions
  • Canopy chlorophyll concentration mapping
  • Nitrogen fertilization mapping

Limitations

  • Requires Red Edge bands (Sentinel-2 exclusive)
CI_RE

Chlorophyll Index Red Edge

NIRRedEdge1

MATHEMATICAL EXPRESSION

Equation for calculating the Chlorophyll Index Red Edge (CI_RE)

CI_{RE} = \left(\frac{NIR}{RedEdge1}\right) - 1

Interpretation

Linear correlation indicator mapping canopy chlorophyll values.

Applications

  • Precision nitrogen applications
  • Forest leaf chlorophyll estimates

Limitations

  • Highly sensitive to atmospheric aerosol noise
GNDVI

Green Normalized Difference Vegetation Index

NIRGreen

MATHEMATICAL EXPRESSION

Equation for calculating the Green Normalized Difference Vegetation Index (GNDVI)

GNDVI = \frac{NIR - Green}{NIR + Green}

Interpretation

Replaces Red with Green to monitor chlorophyll concentration instead of simple canopy structure.

Applications

  • Crop maturity assessments
  • Forest senescence monitoring
  • Chlorophyll density estimation

Limitations

  • Less sensitive than NDVI in low-vegetation desert borders
BSI

Bare Soil Index

SWIR2RedNIRBlue

MATHEMATICAL EXPRESSION

Equation for calculating the Bare Soil Index (BSI)

BSI = \frac{(SWIR2 + Red) - (NIR + Blue)}{(SWIR2 + Red) + (NIR + Blue)}

Interpretation

Combines SWIR and Red with NIR and Blue. High positive values indicate bare soils or urban concrete.

Applications

  • Soil erosion risk classification
  • Fallow crop field tracking
  • Land cover mapping classification

Limitations

  • Confuses asphalt roads and concrete roofs with bare soils
NDBI

Normalized Difference Built-up Index

SWIR1NIR

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference Built-up Index (NDBI)

NDBI = \frac{SWIR1 - NIR}{SWIR1 + NIR}

Interpretation

Values range from -1.0 to 1.0. Positive values indicate urban structures, asphalt, and concrete surfaces.

Applications

  • Urban footprint mapping
  • Impervious surface tracking
  • Urban expansion modeling

Limitations

  • Confuses bare soil or sandy surfaces with built-up areas
AWEI

Automated Water Extraction Index

GreenSWIR1NIRSWIR2

MATHEMATICAL EXPRESSION

Equation for calculating the Automated Water Extraction Index (AWEI)

AWEI = 4 \times (Green - SWIR1) - (0.25 \times NIR + 2.75 \times SWIR2)

Interpretation

Multi-band index optimized to delineate open water surfaces in shadow-rich urban and mountain zones.

Applications

  • Mountain lake boundary tracking
  • Shadow-heavy urban water extraction
  • Wetland classification

Limitations

  • Highly complex coefficients that require strict band calibration
NDSI

Normalized Difference Snow Index

GreenSWIR1

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference Snow Index (NDSI)

NDSI = \frac{Green - SWIR1}{Green + SWIR1}

Interpretation

Exploits the high reflectance of snow in visible green and high absorption in SWIR. Snow displays values > 0.4.

Applications

  • Glacial snow coverage maps
  • Mountain ski resort monitoring
  • Cloud vs snow delineation

Limitations

  • Water surfaces can display high positive values, requiring NIR threshold masking
SMI

Soil Moisture Index

NIRSWIR1

MATHEMATICAL EXPRESSION

Equation for calculating the Soil Moisture Index (SMI)

SMI = \frac{NIR - SWIR1}{NIR + SWIR1}

Interpretation

Indicates water saturation levels within crop leaves and open soil surface layers.

Applications

  • Agricultural drought monitoring
  • Irrigation system scheduling
  • Runoff soil saturation warnings

Limitations

  • Vulnerable to changes in vegetation canopy structures
BI

Bareness Index

RedGreen

MATHEMATICAL EXPRESSION

Equation for calculating the Bareness Index (BI)

BI = \frac{Red - Green}{Red + Green}

Interpretation

Basic ratio mapping reddish soil elements and bare rocky terrain.

Applications

  • Geological mapping
  • Arid landscape erosion hazards

Limitations

  • Highly susceptible to vegetation canopy noise
NDGI

Normalized Difference built-up index with Red-edge

GreenRed

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference built-up index with Red-edge (NDGI)

NDGI = \frac{Green - Red}{Green + Red}

Interpretation

Maps chlorophyll pigments and built-up concrete characteristics.

Applications

  • Urban greenness mapping
  • Urban sprawl assessments

Limitations

  • Low sensitivity in dense forests
RGRI

Red-Green Ratio Index

RedGreen

MATHEMATICAL EXPRESSION

Equation for calculating the Red-Green Ratio Index (RGRI)

RGRI = \frac{Red}{Green}

Interpretation

Indicates relative leaf canopy maturity and stress states.

Applications

  • Crop harvest readiness
  • Forest disease tracking

Limitations

  • Unreliable in sparse soils
NDCI_Clay

Normalized Difference Clay Index

SWIR1SWIR2

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference Clay Index (NDCI_Clay)

NDCI_{Clay} = \frac{SWIR1 - SWIR2}{SWIR1 + SWIR2}

Interpretation

Employs absorption bands characteristic of clay minerals to differentiate rock layers.

Applications

  • Mineral excavation geological audits
  • Soil texture taxonomy

Limitations

  • Blocked by vegetation cover
WRI

Water Ratio Index

GreenRedNIRSWIR1

MATHEMATICAL EXPRESSION

Equation for calculating the Water Ratio Index (WRI)

WRI = \frac{Green + Red}{NIR + SWIR1}

Interpretation

Water bodies display values greater than 1.0, while terrestrial objects present lower values.

Applications

  • Rapid water body classification

Limitations

  • Sensitive to mountain shadows
DVI

Difference Vegetation Index

NIRRed

MATHEMATICAL EXPRESSION

Equation for calculating the Difference Vegetation Index (DVI)

DVI = NIR - Red

Interpretation

Basic vegetation subtraction index, sensitive to canopy cover changes.

Applications

  • Biomass mapping

Limitations

  • Does not normalize for atmospheric or soil brightness
RVI

Ratio Vegetation Index

NIRRed

MATHEMATICAL EXPRESSION

Equation for calculating the Ratio Vegetation Index (RVI)

RVI = \frac{NIR}{Red}

Interpretation

Basic ratio mapping chlorophyll density.

Applications

  • Agricultural crop staging

Limitations

  • Saturates rapidly
NDMI

Normalized Difference Moisture Index

NIRSWIR1

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference Moisture Index (NDMI)

NDMI = \frac{NIR - SWIR1}{NIR + SWIR1}

Interpretation

Identifies moisture stress levels in vegetation canopies. Higher values mean healthy water levels.

Applications

  • Crop water requirements assessments
  • Forest fire danger index calculations

Limitations

  • Vulnerable to soil brightness variations in bare soil areas
NBSI

Normalized Burn Soil Index

SWIR2Red

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Burn Soil Index (NBSI)

NBSI = \frac{SWIR2 - Red}{SWIR2 + Red}

Interpretation

Differentiates burned soil surfaces from green forests.

Applications

  • Post-fire bare soil erosion assessments

Limitations

  • Confuses sandy deserts with burn scars
NDI7

Normalized Difference Index 7

SWIR2Red

MATHEMATICAL EXPRESSION

Equation for calculating the Normalized Difference Index 7 (NDI7)

NDI7 = \frac{SWIR2 - Red}{SWIR2 + Red}

Interpretation

Evaluates geological clay structures and rock weathering properties.

Applications

  • Geological terrain audits

Limitations

  • Obstructed by crop fields
TCARI

Transformed Chlorophyll Absorption in Reflectance Index

RedEdge1RedGreen

MATHEMATICAL EXPRESSION

Equation for calculating the Transformed Chlorophyll Absorption in Reflectance Index (TCARI)

TCARI = 3 \times \left((RedEdge1 - Red) - 0.2 \times (RedEdge1 - Green) \times \left(\frac{RedEdge1}{Red}\right)\right)

Interpretation

Linear chlorophyll sensor index corrected for soil background noise.

Applications

  • Precision chlorophyll estimations

Limitations

  • Highly sensitive to raw band calibrations
MCARI

Modified Chlorophyll Absorption in Reflectance Index

RedEdge1RedGreen

MATHEMATICAL EXPRESSION

Equation for calculating the Modified Chlorophyll Absorption in Reflectance Index (MCARI)

MCARI = \left((RedEdge1 - Red) - 0.2 \times (RedEdge1 - Green)\right) \times \left(\frac{RedEdge1}{Red}\right)

Interpretation

Tracks crop chlorophyll absorption features.

Applications

  • Yield projections

Limitations

  • Obstructed by bare soil background noise
EBBI

Enhanced Built-Up and Bareness Index

SWIR1NIRThermal

MATHEMATICAL EXPRESSION

Equation for calculating the Enhanced Built-Up and Bareness Index (EBBI)

EBBI = \frac{SWIR1 - NIR}{10 \times \sqrt{SWIR1 + Thermal}}

Interpretation

Uses SWIR, NIR, and Thermal bands to separate urban concrete structures from bare dry soils.

Applications

  • Delineating urban core shapes

Limitations

  • Requires thermal bands (Landsat-exclusive)
UI

Urban Index

SWIR2NIR

MATHEMATICAL EXPRESSION

Equation for calculating the Urban Index (UI)

UI = \frac{SWIR2 - NIR}{SWIR2 + NIR}

Interpretation

Reflects the high reflectance of concrete in SWIR2 relative to NIR.

Applications

  • Urban expansion boundary audits

Limitations

  • Confuses bare soil with urban structures