SATELLITE IMAGERY FOR FARMS: WHAT IT CAN AND CANNOT SHOW
Satellite imagery shows variation and change across fields over time — where growth differs, where something has altered since the last clear image, and how a field compares with itself in previous seasons. It does not diagnose cause. Interpretation still requires ground knowledge, and availability depends on third-party satellites, revisit intervals and cloud cover.
UPDATED 2026-09-01 · WRITTEN FOR: FARMERS EVALUATING SATELLITE MONITORING AND VEGETATION INDICES.
WHAT IMAGERY IS GENUINELY GOOD AT
- Showing within-field variation that is hard to see from the gateway.
- Comparing the same field across dates and across seasons.
- Flagging that something changed between two clear images.
- Prioritising which fields to walk when time is limited.
- Providing a dated visual record that can be revisited years later.
HOW TO READ VEGETATION INDICES HONESTLY
Indices derived from imagery summarise reflectance, which correlates with vegetation vigour and cover. They are a comparative signal, best used within a field and against its own history, rather than as an absolute measure compared between farms or sensors.
A low patch is a question, not an answer. Compaction, drainage, pest pressure, nutrition, establishment and previous cropping can all produce a similar picture. The imagery tells you where to look; the ground tells you why.
PLAN AROUND THE PRACTICAL LIMITS
Optical imagery cannot see through cloud, and revisit intervals mean there can be long gaps at exactly the moments you most want a picture. Resolution limits how small a feature can be resolved. These are properties of the available public and third-party sources, not settings that can be turned up.
- AXARA does not own or operate satellites; imagery comes from available public and third-party sources.
- Optical imagery is blocked by cloud and constrained by revisit intervals — coverage is not continuous.
- Resolution limits what can be detected; small features may not be resolvable.
- Indices indicate variation, not cause, disease, nutrient status or yield.
- Attach dated imagery observations to persistent field records so change is comparable over time.
- Show acquisition dates and gaps honestly instead of implying continuous coverage.
- Surface fields where observed change may warrant attention.
- Keep ground observations alongside imagery, so the record holds both.
How often is satellite imagery updated for a field?
It depends on the satellites available for that location and on cloud cover. Useful clear images may be frequent in settled weather and absent for extended periods otherwise.
Can satellites detect crop disease?
No. Imagery can show that an area differs or has changed. Diagnosis requires inspection and, often, laboratory confirmation.
What is NDVI and should I rely on it?
It is a vegetation index derived from reflectance that indicates vigour and cover. Use it comparatively within a field and over time, not as an absolute measurement.
Does satellite imagery replace walking fields?
No. It makes walking fields better targeted by showing where the differences are before you set off.
Does AXARA have its own satellites?
No. AXARA uses available public and third-party Earth observation sources and states their dates and limitations.