GADM data is typically in WGS84 (EPSG:4326). If you are calculating areas (km²), you must reproject the layer to a projected coordinate system (e.g., UTM or Mercator).
The GADM data are freely available for academic use and other non-commercial use. However, there are important restrictions to note:
GADM 3.6 is available in several formats compatible with various software: GeoPackage The current standard format, suitable for Shapefile (.shp): The traditional format used by most GIS software. R Spatial Objects (.rds): download gadm data version 36 work
If you downloaded the whole world GeoPackage (~2.5 GB), you can extract only Level 1 for the Americas:
. Note that these are very large files and may take significant time to download. Available Data Formats GADM data is typically in WGS84 (EPSG:4326)
Remember to respect the licensing terms, choose the appropriate level of detail for your analysis, and leverage the programmatic approaches in Python and R to streamline your workflow.
The browser began its work. Because GADM files are high-resolution (meaning they follow the exact curves of coastlines and rivers), they aren't small. However, there are important restrictions to note: GADM 3
This is the most efficient way to get data if you only need a specific region. You can select from over 200 countries on the Country Download page .
Use the readRDS() function for .rds files or the sf package to load GeoPackages. Specialized packages like GADMTools can further streamline the process.
By following these resources and tips, you can unlock the full potential of GADM data version 36 and take your research or analysis to the next level.
A single file format containing all layers. This is the recommended format for modern GIS software like QGIS.