Spalding & Holbeach Fens · crop year

Fen Crop Monitor

Crop type and field checks from free Sentinel-2 imagery. The model never saw a label from this area: it was trained on Rural Payments Agency ground observations from 30 other parts of England.

How it scores

Held-out test zones · RPA ground observation points

How it scores

Accuracy at inspector-checked points

Overall accuracy, with 95% bootstrap intervals in small type. Every map is scored on exactly the same points.

How early in the season the crop is known

2023 is the fairest comparison with CROME: its score here matches its published 2023 accuracy (90.1%). In 2024 and 2025 CROME scores about 97% at these points, far above any published figure; its confidence collapses away from them, which suggests it is now trained on these same parcels. Its labels, though, agree with ours just as often far from these points (81% beyond 2 km vs 75% in fields containing one), so it doesn't look much less accurate there.
2024 is hard for both independent maps (ours and UKCEH), mostly confusing winter and spring barley; plausibly linked to the very wet 2023–24 winter, which delayed drilling (not yet verified).
The winter cover check is indicative: RPA records of SFI cover-crop agreements are not a reliable per-parcel label for a given winter, so it has not been validated precisely.