My task is to upload geojson, add data from corresponding csv, drop some columns, then save it back to geojson.

However, after I did everything, added csv data (gj.join(df) ), etc, I can't save it to geojson getting this Keyerror:

KeyError Traceback (most recent call last)
in ()
----> 1 x = newGj.to_json()
2 x

/usr/local/lib/python2.7/site-packages/geopandas/geodataframe.pyc in to_json(self, na, *kwargs)
249 return json.dumps(
250 {'type': 'FeatureCollection',
--> 251 'features': [feature(i, row) for i, row in self.iterrows()]},
252 *kwargs )

/usr/local/lib/python2.7/site-packages/geopandas/geodataframe.pyc in feature(i, row)
245 'properties':
246 dict((k, v) for k, v in iteritems(row) if k != self._geometry_column_name),
--> 247 'geometry': mapping(row[self._geometry_column_name]) }
249 return json.dumps(

KeyError: None
  • KeyError generally means that a key that is being accessed in a dictionary doesn't actually exist. Based on the stack trace, it looks like the internal geometry column name is set to None. Aug 26, 2015 at 13:04
  • well I first upload geoDf and it works good - I can parse it to geoJson, etc. but as soon as I add another dateseries (column) or dataframe (columns), it does not work. however, printing DF shows that geometry column has a correct name 'geometry' Aug 26, 2015 at 19:20

1 Answer 1


what commands are you actually using?

EDIT lead with misleading/false "no way to 'write to geojson' " comment originally

Looking at the documentation I don't see a way to "write to geojson" other than geoDF.to_file() for which you'll get a shapefile or need to specify an OGR driver.

I like the below option using geoDF.to_json() better because it simply returns a GeoJSON formatted string.

Try something like this:

with open('test.geojson', 'w') as f:

WARNING: it looks like GeoPandas.to_json() does not specify the CRS so reading back in the data GeoPandas.read_file() will assume your data are in WGS (EPSG=4326). I don't see how to specify the crs in the kwargs so for me easier to simply reproject the data (geoDF.to_crs(epsg=4326, inplace=True)) before writing to file.

Alternatively the below also works for me BUT

  • it gives me "WARNING:Fiona:CPLE_NotSupported in dataset .geojson does not support layer creation option ENCODING" when I read back in, and
  • not all geometries written using the to_file() method are equal to gemetries written with the f.write() method. I assume this has something to do with how GeoPandas handles the underlying driver but I haven't looked into it further

nyc_blocks.to_file('geoDF.geojson', driver="GeoJSON")

  • 1
    That ENCODING warning also appears in windows, just before crashing python (2.7, 32 bit - Fiona 1.7.0 - GDAL 2.0.3)
    – Efren
    Oct 19, 2016 at 6:54
  • also, it ACTUALLY corrupts encoding Dec 29, 2016 at 4:37
  • This worked for me with the caveat that everything was saved as a FeatureCollection.
    – denson
    Jun 14, 2019 at 18:11

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