title: geodataframe.to_file Invalid field type <class 'bytes'>
body: <p>I am processing shp files, and i'm having problems saving a geodataframe in a shp file.</p>
  
  <pre><code>import pandas as pd
  import numpy as np
  import os
  import geopandas
  location = '/home/braulio/Documents/example.shp'
  datos = geopandas.read_file(location, encoding='UTF-8')
  </code></pre>
  
  <p>I don't have problems procesing data but when i try to save</p>
  
  <pre><code>A.to_file(r"/home/braulio/Documents/example2.shp")
  </code></pre>
  
  <p>and return an error:</p>
  
  <pre><code>ValueError                                Traceback (most recent call last)
  &lt;ipython-input-23-6a842789b4b4&gt; in &lt;module&gt;
  ----&gt; 1 A.to_file(r"/home/braulio/Documents/example2.shp")
  
  ~/anaconda3/envs/braulio/lib/python3.7/site-   packages/geopandas/geodataframe.py in to_file(self, filename, driver,   schema, **kwargs)
  411         """
  412         from geopandas.io.file import to_file
  --&gt; 413         to_file(self, filename, driver, schema, **kwargs)
  414 
  415     def to_crs(self, crs=None, epsg=None, inplace=False):
  
  ~/anaconda3/envs/braulio/lib/python3.7/site-packages/geopandas/io/file.py in to_file(df, filename, driver, schema,**kwargs)
  109         with fiona.open(filename, 'w', driver=driver, crs=df.crs,
  110                         schema=schema, **kwargs) as colxn:
  --&gt; 111             colxn.writerecords(df.iterfeatures())
  112 
  113 
  
  ~/anaconda3/envs/braulio/lib/python3.7/site-packages/fiona/collection.py in writerecords(self, records)
  347         if self.mode not in ('a', 'w'):
  348             raise IOError("collection not open for writing")
  --&gt; 349         self.session.writerecs(records, self)
  350         self._len = self.session.get_length()
  351         self._bounds = self.session.get_extent()
  
  fiona/ogrext.pyx in fiona.ogrext.WritingSession.writerecs()
  
  fiona/ogrext.pyx in fiona.ogrext.OGRFeatureBuilder.build()
  
  ValueError: Invalid field type &lt;class 'bytes'&gt;
  </code></pre>