| Problem | Solution |
|---------|----------|
| .prj missing, coordinate system unknown | Manually set CRS to EPSG:4326 (WGS84). |
| Attribute text looks garbled (e.g., “Côte”) | Encoding issue. Open Shapefile with UTF-8 or use .cpg file. In QGIS, set “Data source encoding” to UTF-8. |
| Multiple files for Level 0, 1, 2 – which one to use? | Use gadm36_COUNTRYCODE_0.shp for borders, _1 for states, _2 for districts. GeoPackage contains all layers. |
| Cannot dissolve internal boundaries (e.g., show only country outline) | Use Vector → Geoprocessing → Dissolve on Level 1 features, or simply re-load Level 0. |
| File size too big for memory | Use GeoPackage with spatial indexing, or filter by attribute before loading. |
After download, check inside the file (e.g., in R):
library(sf)
gadm <- st_read("gadm36_JPN_0.gpkg")
attributes(gadm)$GADM_VERSION
Should return "3.6".
import requests import zipfile import osgdf_shp = gpd.read_file("gadm36_USA_1.shp")
print(gdf.crs) # EPSG:4326 print(gdf.head())download gadm data version 36 work
GADM 3.6 is free for academic and non-commercial use but has restrictions: | Problem | Solution | |---------|----------| |
For commercial use, you must obtain permission from the original data sources (check GADM’s commercial licensing page).
provinces = gdf_all[gdf_all["LEVEL"] == 1] Should return "3