A hyperspectral vegetation index that uses the red edge spectral region to assess vegetation health and chlorophyll content. It is particularly sensitive to vegetation stress and early detection of plant diseases.

Used in crop monitoring, forest monitoring, and mineral exploration.

When to use

  • Time-series monitoring of crop health, growth stages, and stress detection
  • Land cover classification and vegetation type discrimination
  • Biomass estimation and net primary productivity studies
  • Drought impact assessment over agricultural and forest areas
  • Phenology tracking — green-up, peak season, and senescence
  • Vegetation stress detection
  • Chlorophyll content assessment

Limitations

  • Saturates in dense canopies (LAI > 3) — values plateau and lose discrimination ability
  • Sensitive to atmospheric scattering, especially blue-band haze
  • Soil background contaminates measurements in sparsely vegetated areas
  • Sun-sensor geometry (BRDF effects) introduces variability across acquisitions
  • Cloud cover and shadows produce invalid pixels that need masking

What the values mean

-1 Water / Snow
-0.1 Bare ground / Built-up
0.1 Sparse / Stressed
0.3 Moderate vegetation
0.5 Healthy vegetation
0.7 Dense canopy
Surface typeTypical VOG1
Open water, snow-0.3 to -0.1
Bare soil, urban-0.1 to 0.2
Sparse or stressed crops0.2 to 0.4
Healthy crops, grassland0.4 to 0.7
Dense forest, peak season0.7 to 0.9

General Formula

re1 720
re2 740

Sensor-Specific Formulas

Most-used sensors — click to show code below

SensorProviderFormulaBand Mapping
WyvernBand 19 / Band 18re1→Band 18, re2→Band 19
ESAB6 / B5re1→B5, re2→B6

Spectral Band Visualization — Dragonette-1

Code Examples

Adapted for Dragonette-1 bands —

vog1_dragonette-001.py

Frequently Asked Questions

What is the VOG1 (Vogelmann Red Edge Index 1) and when should I use it?

A hyperspectral vegetation index that uses the red edge spectral region to assess vegetation health and chlorophyll content. It is particularly sensitive to vegetation stress and early detection of plant diseases. Vegetation indices quantify plant health, biomass, and photosynthetic activity by exploiting the contrast between how plants absorb visible light for photosynthesis and reflect near-infrared radiation from their cellular structure. VOG1 is particularly suited for vegetation stress detection, chlorophyll content assessment, early disease detection. The general formula is RE2 / RE1, which requires re1 and re2 spectral bands.

Which satellite sensors can I use to calculate VOG1?

VOG1 is supported by 3 satellite sensors in our database, including Dragonette-1, Dragonette-2/3, Sentinel-2. Each sensor uses different band designations — for example, Dragonette-1 uses the formula Band 19 / Band 18, while Dragonette-2/3 uses Band23 / Band22. Select a sensor above to see its specific band mapping.

What spectral bands does VOG1 require and why?

VOG1 requires re1 (720), re2 (740). Vegetation strongly absorbs red light for photosynthesis while reflecting near-infrared light from its mesophyll cell structure, making this contrast a reliable indicator of plant vigour.

How do I calculate VOG1 in Python or R?

Both Python and R code samples are provided above. In Python, use rasterio to load individual band GeoTIFF files and numpy for the arithmetic. In R, the terra package handles raster operations efficiently. The key is to load bands as floating-point arrays to avoid integer division, and to handle division-by-zero cases where the denominator equals zero. For production use, consider applying a valid data mask to exclude no-data pixels before calculation.

How does VOG1 compare to NDVI and other vegetation indices?

While NDVI is the most common vegetation index, VOG1 provides complementary information that NDVI cannot capture on its own. The choice of index depends on your application, sensor availability, and atmospheric conditions.

VOG1 vs other vegetation indices

IndexNameHow it differs
ARIAnthocyanin Reflectance IndexAlternative vegetation index — different band combination
mARIModified Anthocyanin Reflectance IndexRefined formulation for specific conditions
ARVIAtmospherically Resistant Vegetation IndexAtmospherically corrected version
ARVI2Atmospherically Resistant Vegetation Index 2Atmospherically corrected version

Related Vegetation Indices

References

Vogelmann et al. (1993). Red Edge Spectral Measurements from Sugar Maple Leaves.
le Maire et al. (2004). Towards universal broad leaf chlorophyll indices using PROSPECT simulated database and hyperspectral reflectance measurements.

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