The official yearly series (1985–2025)
The authors' country statistics file supplies an extent figure for every year; Atlas loads it alongside the seven mapped years.
Atlas keeps seven full polygon maps per country in its database (1996, 2000, 2005, 2010, 2015, 2020, 2025) to save space, but the Global Mangrove Watch authors also publish a yearly statistics table for every year from 1985 to 2025.
Atlas stores that table inside each country's latest dataset (field official_annual_ha) and draws it on the Mangrove Change page as the "Every year" chart.
How the two relate. The seven mapped years are Atlas' own measurements of the polygons; the 41-year line is the authors' figure. The two differ by a constant 2.3%, so the shapes match and only the level differs.
All 41 yearly maps are downloaded and archived on the server even though only seven are loaded into the database. They can be loaded on request (about 0.4 GB of database space each).
Related reading
More in Methodologies
- Fragmentation metrics
- Why Atlas totals are 2.3% higher than the official figures
- How units are harmonised on import
- Confidence labels: calculated, illustrative, assumed
- How Global Mangrove Watch maps are made
- Versions and cumulative updates
- Spatial statistics: Moran's I and Getis-Ord Gi*
- Field plots versus the map
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