A hotspot is a detected pixel, not a fire outline
NASA FIRMS locates a detection at the centre of a satellite pixel containing a fire or another thermal anomaly. That pixel can contain more than one heat source; thermal anomalies can also include volcanic activity. The point does not specify the exact location or area of burning within the pixel. NASA explains these distinctions in its hotspot definition.
MODIS detections have a nominal scale of about one kilometre, while VIIRS active-fire detections use approximately 375-metre pixels. Actual footprints vary with viewing geometry. These are observation scales, not claims that each fire is that wide. A sharper-looking map marker does not make the source measurement more precise.
Why a fire may be missing from the map
Detection depends on conditions including cloud or smoke, fire size and the satellite viewing angle. NASA's MODIS detection FAQ describes these limitations. The absence of a hotspot is not proof that there is no fire, and the presence of a point should not be treated as a verified local incident report.
Before comparing two views, check which product and observation times each uses. A useful comparison keeps the source, time window and map area consistent. If one of those details is missing, record that uncertainty rather than interpreting a change in the number of markers as a confirmed change on the ground.
Why counting dots does not measure burned area
Repeated observations may describe the same fire. Adding all hotspot pixels together does not produce a reliable burned-area measurement or an operational fire perimeter. NASA's FIRMS FAQ on wildfire area distinguishes these uses. A separate perimeter product requires its own method, date and source.
Keep that distinction when sharing a screenshot: describe visible points as detections in the selected data, not as a count of independent wildfires. Do not draw an apparent evacuation boundary by joining the outermost dots. The map display alone cannot support that interpretation.
Reading fire data in PocketWorld
Use the wildfire map guide to enter the disaster explorer. Select the fire layer, inspect an available record and check the named provider and freshness context. NASA FIRMS detections and NASA EONET event context are different kinds of records, so keep their provenance visible when comparing them.
PocketWorld is an informational explorer, not an emergency warning service. Missing, delayed or retained data must not be treated as an all-clear. For current local restrictions and safety instructions, consult the responsible authority. Read our source registry and methodology for more about how observations reach the map.
Data sources
References are linked beside the explanations above. This evergreen guide does not report current incidents.