Moisture Stress Index

Simple ratio index for detecting vegetation water stress and moisture content. Higher values indicate greater water stress in vegetation. 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. MSI is particularly suited for vegetation water stress, drought monitoring, irrigation management. The general formula is 1600nm / 820nm, which requires NIR and SWIR1 spectral bands.

MSI is supported by 2 satellite sensors in our database, including SuperView-2, WorldView 3. Each sensor uses different band designations — for example, SuperView-2 uses the formula SWIR / NIR1, while WorldView 3 uses SWIR2 / NIR1. Select a sensor above to see its specific band mapping.

MSI requires NIR (820 nm), SWIR1 (1600 nm). 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.

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.

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