FORMA alert thresholds

WRI/GFW/FORMA/thresholds
Dataset Availability
2012-01-01 - 2016-01-01
Dataset Provider
Earth Engine Snippet
ee.Image("WRI/GFW/FORMA/thresholds")
Tags
forests deforestation modis monitoring daily forma gfw wri

Description

FORMA alerts are detected using a combination of two MODIS products: NDVI (Normalized Difference Vegetation Index) and FIRMS (Fires Information for Resource Management System). NDVI updates are processed every 16 days, while fire updates are processed daily. Models are developed individually for each ecogroup to relate the two inputs to the area of clearing, using the Hansen annual tree cover loss data to train the model. The minimum threshold to qualify as an alert is 25% of the pixel cleared, though thresholds vary by ecogroup to minimize false positives. Here is an example script for a quick introduction to the FORMA datasets.

This image contains the thresholds at which, when crossed, a FORMA alert is produced. The values are equal to max(25,40%*RegionalMax), where RegionalMax is the historical maximum clearing for a pixel in this ecogroup. Ecogroup geometries can be found here.

Bands

Resolution
250 meters

Bands

Name Units Min Max Description
delta_bound % 25 40

The thresholds at which, when crossed, a FORMA alert is produced

Image Properties

Image Properties

Name Type Description
start_year INT

The first year included in determining the historical max for the ecogroup

year INT

The last year included in determining the historical max for the ecogroup

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.

Explore in Earth Engine

var dataset = ee.Image('WRI/GFW/FORMA/thresholds');
var thresholds = dataset.select('delta_bound');
var visParams = {
  min: 0.0,
  max: 50.0,
};
Map.setCenter(25.73, -7.61, 2);
Map.addLayer(thresholds, visParams, 'Thresholds for FORMA alerts');

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