GADM version 3.6 (released May 6, 2018) is a foundational dataset for spatial analysis, delimiting 386,735 administrative areas worldwide. While newer versions like 4.1 exist, 3.6 remains widely used due to its stable GID identifier system, which was specifically fixed in this release after errors in version 3.4. How to Download Version 3.6
GADM 3.6 uses GID_0, GID_1, GID_2 as unique identifiers. Merge using these columns – more reliable than names (which may have spaces/case issues). download gadm data version 36 work
| Format | Best for | Notes |
|--------|----------|-------|
| Shapefile (.shp) | QGIS, ArcGIS (all versions) | Universal, but requires all 4–5 component files. |
| GeoPackage (.gpkg) | QGIS, modern GIS | Single-file, better performance, highly recommended. |
| R data (.rds) | R users (sf or sp packages) | Loads directly with readRDS(). |
| KMZ | Google Earth, web mapping | Limited attribute access. | GADM version 3
usa_shp <- st_read("gadm36_USA_1.shp")
import sqlite3
conn = sqlite3.connect("gadm36_levels.gpkg")
sub = gpd.read_file(conn, layer="level_1", bbox=(-130, 20, -60, 60))
GADM (Database of Global Administrative Areas) is the gold standard for boundary data. Version 3.6, released in late 2020 (with minor updates into 2021), remains one of the most widely used versions due to its stability, licensing clarity, and compatibility with legacy systems. However, novice users often struggle with file formats, projection mismatches, and API changes. GADM (Database of Global Administrative Areas) is the
Note for older R versions: GADM v3.6 attribute names are clean but may include special characters (e.g., “São Paulo”). Use st_read(..., stringsAsFactors = FALSE) to avoid factor conversion issues.
gdf_mercator = gdf.to_crs("EPSG:3857") # Web Mercator
gdf_utm = gdf.to_crs("EPSG:32631") # UTM zone 31N