All alerts published by MapBiomas Alerta undergo a rigorous three-step process consisting of validation, refinement, and auditing.

• Validation – Alerts undergo a visual assessment by expert analysts using daily PlanetScope imagery, filtering out duplicates and selecting the best satellite evidence (before and after) with minimal cloud cover. At this stage, “false positives” are ruled out using technical criteria such as seasonality, burning without a change in land use, or previous interventions, ensuring that only events involving actual loss of natural vegetation proceed in the process.
• Refinement – The affected area is delineated using supervised pixel sampling on both undisturbed and altered surfaces. The resulting polygon is cleaned to remove noise, and finally, a pressure vector (such as mining, agriculture, or natural phenomena) is assigned to it based on the photointerpretation of the observed changes between the selected images.
• Audit – Each refined alert is verified by a regional technical supervisor, who checks the image quality, the boundaries of the polygon, the consistency of the dates, and the correct categorization of the cause of the event. This final quality control ensures the integrity of the data before its official release.
  

Additional details regarding the methodology for validating and publishing alerts are available at the following link