Understanding Sentinel-2 imagery, NDVI baselines, cloud masking, and automated deforestation detection — the technology that makes satellite-verified EUDR compliance possible.
Copernicus is the European Union's Earth observation programme, coordinated by the European Commission and implemented in partnership with the European Space Agency (ESA), EU Member States, and EU agencies. It is the largest Earth observation programme in the world, providing continuous, free, and open data about our planet from a constellation of dedicated satellites and contributing missions.
For EUDR compliance, Copernicus is particularly significant because the European Commission has explicitly referenced it as a data source for verifying deforestation-free supply chains. The programme's Sentinel satellite family provides the imagery needed to detect land-use changes at the scale required by the regulation — covering every production plot, in every country, with consistent and repeatable measurements.
Unlike commercial satellite providers that charge per image or per square kilometre, Copernicus data is freely available under an open licence. This means any operator, compliance platform, or competent authority can access the same imagery — creating a level playing field for verification.
The Sentinel-2 mission consists of two identical satellites — Sentinel-2A and Sentinel-2B — orbiting the Earth in a sun-synchronous orbit at 786 km altitude. Together, they provide global coverage with a revisit time of approximately 5 days at the equator. Here are the specifications that matter for EUDR due diligence:
The Normalized Difference Vegetation Index (NDVI) is the primary metric used to assess vegetation health from satellite imagery. It exploits a fundamental property of plant biology: healthy green vegetation absorbs most visible red light for photosynthesis while strongly reflecting near-infrared (NIR) light. Bare soil, water, and built-up areas do not show this pattern.
The formula is straightforward:
NDVI = (NIR − Red) / (NIR + Red)
NDVI values range from −1 to +1:
A significant drop in NDVI between the baseline period and the current period is a strong indicator of deforestation or forest degradation. For example, if a plot showed NDVI values of 0.75 in mid-2020 but now shows 0.25, that suggests the forest cover has been removed and replaced with bare soil or low vegetation — exactly the kind of change the EUDR is designed to detect.
In addition to NDVI, the Normalized Difference Moisture Index (NDMI) uses the shortwave infrared band to detect changes in vegetation water content. NDMI is particularly useful for identifying forest degradation — situations where the canopy is thinned or stressed but not completely removed.
EUDR compliance verification is fundamentally a change detection problem: has the land cover on a specific plot changed between the cutoff date (31 December 2020) and the present? Here is how satellite-based change detection works in practice:
The first step is creating a reliable baseline image of each production plot from around the cutoff date. Rather than using a single satellite image from 31 December 2020 (which might be cloudy or affected by seasonal variation), analysts typically create a composite image from multiple acquisitions during a defined baseline window — commonly June to August 2020 for tropical regions, when cloud cover tends to be lower.
The composite is built by selecting the best (least cloudy) pixel from each available image in the window, producing a cloud-free representation of the land surface during the baseline period. NDVI and NDMI values are calculated from this composite to establish the baseline vegetation state.
The same compositing process is applied to recent imagery — typically the most recent 3–6 months — to create a current-state representation of each plot. This accounts for seasonal variation and ensures that temporary changes (such as deciduous leaf drop) are not mistaken for deforestation.
The change detection algorithm compares the baseline and current NDVI/NDMI values for each pixel within the plot boundary. A significant negative change (drop in vegetation index) that exceeds a defined threshold is flagged as potential deforestation or degradation. The threshold is calibrated to balance sensitivity (detecting real changes) against specificity (avoiding false alarms from natural variation).
Tropical regions — where most EUDR-regulated commodities are produced — present a major challenge for optical satellite monitoring: persistent cloud cover. In equatorial Africa, Southeast Asia, and parts of South America, cloud cover can exceed 80% during the wet season, making individual satellite images unusable.
Two techniques address this:
The combination of Sentinel-2's 5-day revisit time and seasonal compositing means that even in the cloudiest tropical regions, reliable vegetation assessments can be produced for most production plots. In rare cases where cloud cover is truly impenetrable for extended periods, supplementary data sources (such as Sentinel-1 radar, which penetrates clouds) can fill the gaps.
Not all land-use changes look the same from space. Converting dense tropical forest to a cattle ranch produces a very different spectral signature than converting secondary forest to a coffee plantation under shade trees. Effective EUDR monitoring systems use commodity-specific thresholds to account for these differences:
The final step in the satellite analysis pipeline is translating raw change detection results into an actionable compliance verdict for each production plot. A typical classification system assigns one of three risk levels:
The satellite analysis report — including the baseline and current imagery, NDVI/NDMI values, change maps, and risk classification — becomes part of the operator's due diligence documentation. It provides the auditable, evidence-based foundation that competent authorities expect when reviewing EUDR compliance.
By combining freely available Copernicus data with automated analysis pipelines, operators can now verify deforestation-free status across thousands of production plots in a matter of hours — a task that would have been impossible through field visits alone. This is the technology that makes EUDR compliance at scale not just feasible, but practical.
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