Glossary
Yield mapping
Recording crop yield by GPS location during harvest to build a spatial map of how output varies across a field.
Also called: yield map, yield monitoring
Yield mapping is the practice of recording how much a field produces at each point across it, rather than as a single average for the whole field. A yield monitor mounted on a combine measures grain flow and moisture continuously during harvest and pairs each reading with a GPS position, producing thousands of point measurements that are interpolated into a color-coded map showing where yield was high and where it was low.
The resulting map is a core input to precision agriculture: it is overlaid against soil type, elevation, and prior variable-rate application records to explain why a low-yield zone underperformed, whether from drainage, compaction, pest pressure, or a seeding-rate mismatch. This differs from crop modeling, which forecasts yield from weather and soil inputs before harvest; yield mapping records what actually happened afterward and is used to validate or recalibrate those forecasts.
The main pitfall is treating a single season's map as definitive. Yield varies with that year's rainfall and pest pressure, so agronomists compare maps across multiple seasons before drawing conclusions about a zone's underlying productivity. Raw monitor data also needs cleaning for GPS drift, header-width errors, and harvest-speed artifacts before it is reliable enough to guide input decisions in geographic information system software.
Last reviewed September 22, 2026