Showcasing the workflow of geocoding an area-of-interest polygon using Nominatim

nominatim_geocoder.py

import sys
import geopandas as gpd
from geopy.geocoders import Nominatim
from shapely import wkt

# To run this script, you need to have geopy and geopandas installed:
# python -m venv .venv
# source .venv/bin/activate
# python -m pip install geopy geopandas


def retrieve_area(aoi_name: str, user_agent: str) -> gpd.GeoDataFrame:
    """Geocode area of interest."""
    try:
        geolocator = Nominatim(user_agent=user_agent)
        location = geolocator.geocode(aoi_name, geometry='wkt', exactly_one=False)
        
        # Initialize lists to store data
        osm_ids = []
        names = []
        geometries = []

        for loc in location:
            osm_ids.append(loc.raw['osm_id'])
            names.append(str(loc))
            geometries.append(wkt.loads(loc.raw['geotext']))

        # Create GeoDataFrame from lists
        aoi_gdf = gpd.GeoDataFrame(
            {
                'osm_id': osm_ids,
                'name': names,
                'geometry': geometries
            }, 
            crs='EPSG:4326'
        )
    except Exception as e:
        print(f'Could not retrieve area: {e}')
        sys.exit(0)

    return aoi_gdf


if __name__ == '__main__':
    aoi_name = 'Rio de Janeiro'
    user_agent = 'random_user'

    aoi_gdf = retrieve_area(aoi_name, user_agent)

    aoi_gdf.to_file('output.gpkg', driver='GPKG')
    print('Area of interest saved to output.gpkg')
    

More info on GeoPy and Nominatim here