Error when loading pickled saved df with version < 0.6.3

I’m using geopandas for a while and am used to save my gdf as pickle files, and then open it directly with pandas. I have some old files that I want to open. I guess the files were saved as my pandas version was 0.6.2, but I’m not sure.

Now that I’m trying to re-open it I get the following error : AttributeError: 'GeoDataFrame' object has no attribute '_item_cache'

Here is a code sample which makes the problem reproducible : with geopandas==0.6.3 run

import pandas as pd
import geopandas as gpd
from shapely.geometry import Point

data = [[3, 45, 1], [3.1, 45.2, 1.5], [2.7, 44.5, 2.1]]
data = pd.DataFrame(data, columns=['Longitude', 'Latitude', 'value'])
data['geometry'] = list(zip(data['Longitude'], data['Latitude']))
data['geometry'] = data['geometry'].apply(Point)
data = gpd.GeoDataFrame(data)

data.to_pickle('df.pkl')

And then with geopandas==0.8.0 (or 0.7.0) try :

import pandas as pd
df = pd.read_pickle('df.pkl')

It should raise the same error.

• I’m not sure if it’s a problem of pickle or geopandas, I naively tried to grep __item_cache in the gpd code but it wasn’t successful either with 0.6.3 or with 0.8.0
• This is troublesome because I have to keep 0.6.3 in the meantime unless someone sees a turnaround (I could make a “clean save” of all my pickled gdf with 0.6.3 which can be read with 0.8.0 but I don’t know if this is possible)
• Maybe my workflow is terrible and then I’ll gladly take some advice !

[martinfleis]

I am not sure if there is a way how to open old pickle in new pandas. Pickle as a format is not meant for a data storage, especially not with compatibility between versions. The nature of pickle itself does not allow that, if there are significant changes to pandas or geopandas in between the versions. These could be under the hood but still makes the pickle file unusable. My recommendation would be to save those pickle files as some standard geospatial data format with 0.6.3 so you can open that in any other version.

[jorisvandenbossche]

Closed by #1511