FORMA Global Forest Watch Deforestation Alerts, 500m [deprecated]

Dataset Availability
Dataset Provider
Earth Engine Snippet
alerts deforestation forest forma geophysical gfw modis nasa wri


FORMA is a MODIS-based deforestation alerting system for the humid tropical forests. FORMA is designed for quick identification of new areas of tree cover loss. The system analyzes data gathered daily by the MODIS sensor, which operates on NASA's Terra and Aqua satellites. The FORMA alerts system then detects pronounced changes in vegetation cover over time, as measured by the Normalized Difference Vegetation Index (NDVI), a measure of vegetation greenness. These pronounced changes in vegetation cover are likely to indicate forest being cleared, burned, or defoliated. An alert is added to the dataset by setting the pixel value to the date at which a change was detected. FORMA alerts only appear in areas where the probability of tree cover loss is greater than or equal to 50%. FORMA data has 500-meter spatial resolution and twice-monthly update interval. FORMA alerts start in January 2006.


500 meters


Name Units Min Max Description
constant seconds 1.13498e+09* 1.43392e+09*

Seconds since Jan 1, 1970

* estimated min or max value

Terms of Use

Terms of Use

The FORMA datasets are available without restriction on use or distribution. WRI does request that the user give proper attribution and identify WRI and GFW, where applicable, as the source of the data.


  • Hammer, Dan, Robin Kraft, and David Wheeler. 2013. FORMA Alerts. World Resources Institute and Center for Global Development.

Explore with Earth Engine

Code Editor (JavaScript)

var dataset = ee.Image('FORMA/FORMA_500m');

var visualization = {
  bands: ['constant'],
  min: 1134979200.0,
  max: 1433919600.0,
  palette: ['ff0000']

Map.setCenter(-51.482, -0.835, 6);

Map.addLayer(dataset, visualization, 'Alert Areas');
Open in Code Editor