Concatenating two geodataframes needs CRS Adjustment

Question

I have two geodataframes which I would like to concatenate. I have tried this:

test=gpd.GeoDataFrame( pd.concat( [gdf1, gdf2], ignore_index=True) )

where print(gdf1.columns) and print(gdf2.columns) both give

Index(['ville', 'objectid', 'geometry', 'area_km2'], dtype='object')

and where print(gdf1.geometry.crs) and print(gdf2.geometry.crs) both give +init=epsg:4326 +type=crs

yet i am getting this error:

ValueError: Cannot determine common CRS for concatenation inputs, got ['WGS 84', 'WGS 84']. Use to_crs() to transform geometries to the same CRS before merging.

Output is truncated. View as a scrollable element or open in a text editor. Adjust cell output settings...

How can this be possible when both CRS are on 4326 (GPS)

Any idea?

Answer 1

Try resetting the crs's to make sure they are the same:

gdf1 = gdf1.to_crs("epsg:4326")
gdf2 = gdf2.to_crs("epsg:4326")

then concat