Vegetation indices – the cornerstone of satellite crop monitoring

Satellite crop monitoring allows farmers to regularly assess the condition of the crops withiout the need of personal visits in the fileds. Vegetation indices are the basic tool that provides the near-real time information about the crop condition.

Satellite-based assessment could be both qualitative and quantitative assessment, and thus provides more real information than potential vegetation maps, which are based on vegetation-climatic factors.

How does it work

Vegetation indices use specific properties of different surfaces manifested by diverse reflectance and absorption of electromagnetic radiation (which are measured with satellites). Those specific surface properties cause that under the same conditions on the same day and at the same wavelength a tree in the Amazon rainforest and a tree in the middle of the African Sahel will reach different values.

Similarly, an agricultural crop may have at the same time different values within a single field, dependent whether it is located in the shade of a forest (with a lack of sunlight), in a waterlogged area (too much water leading to vegetation death) or in a place where the ratio of sunlight, moisture and nutrients is in balance.

A tree in the Amazon rainforest reaches higher values of NDVI in comparison to a tree in African Sahel measured by Sentinel-2 and displayed by DynaCrop.

The key aspect of creating indices is the feature of satellites, which are measuring at the same time at multiple wavelengths (so-called multispectral and hyperspectral sensors). Sentinel 2, which is primarly used by DynaCrop offers 13 different wawelengs, some of them specially designed for vegetation monitoring.

Each of the indices uses a combination of values ​​measured at different wavelengths at the same time and in the same place to determine the required parameters such as health of the vegetation, the chlorophyll content in the leaves, the amount of biomass, etc.

Which vegetation indices you can find in DynaCrop

At the moment, we enable you to use following vegetation indices:

  • NDVI – normalized difference vegetation index
  • EVI – enhanced vegetation index
  • NDWI – normalized difference water index
  • NDMI – normalized difference moisture index
  • LAI – leaf area index
  • FAPAR – fraction of photosynthetically active radiation
  • CCC – canopy chlorophyll content
  • CWC – canopy water content
  • CWC – canopy water content
  • MSAVI2 – modified soil-adjusted vegetation index
  • NDRE – normalized difference red edge index (B05, B08)
  • NDREX – normalized difference red edge index (B04, B09)

To understand them more in detail, check our technical documentation.

Would you like to discuss specific indicies or their use? Let us know and we will be happy to talk to you.

World from Space, s.r.o., Pellicova 624/3, 602 00 Brno, Czech Republic. Společnost je zapsána v obchodním rejstříku u Krajského soudu v Brně, oddíl C, vložka 101899. Copyright 2020

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