Wildfire data field guide
MODIS vs VIIRS for Wildfire Detection: what is the difference?
Both satellite systems feed active-fire products into NASA FIRMS, but their spatial resolution and detection behavior differ. For incident reconstruction, sensor identity belongs with every hotspot.
Resolution
VIIRS provides a finer active-fire footprint than MODIS.
FIRMS distributes MODIS and VIIRS active-fire / thermal-anomaly products. MODIS fire detections are commonly represented at about kilometre scale, while the VIIRS I-band active-fire product uses approximately 375 m resolution.
Long-running global active-fire record with roughly 1 km fire-pixel scale in FIRMS products.
375 m active-fire product designed for improved response to smaller fires and better spatial detail.
What finer resolution changes
Smaller pixels improve spatial discrimination—not exact fire-edge mapping.
VIIRS can locate thermal activity more precisely than a kilometre-scale MODIS pixel and often detects smaller or more spatially detailed fire features. But a VIIRS hotspot is still a sensor detection, not a surveyed perimeter.
Time matters
A satellite sees a snapshot at overpass.
- Each detection has an acquisition date and time.
- A fire can move between observations.
- Cloud can hide active burning.
- Day/night conditions and sensor geometry affect detection behavior.
- Near-real-time products can later be replaced by standard science-quality processing.
Black Box use
Store the sensor with the detection.
Tecnobosque’s evidence model should preserve sensor, platform, acquisition time, confidence, FRP and spatial footprint rather than reducing all satellite points to a generic “hotspot” layer.
Sources
NASA FIRMS.
NASA FIRMS — Active Fire Data ↗
NASA FIRMS — VIIRS active-fire product ↗
NASA FIRMS — MODIS active-fire product ↗
Published 21 September 2026.