Converting dataframe with Polygon to GeoDataFrame

I imported a shapefile in the form of a pandas.dataframe and ran operations on it. But I can’t convert the dataframe to a geodataframe. I tried with gpd.GeoDataFrame, and with wkt.loads. I think it’s because of the format of my geometry: they’re Polygon Z:

0 POLYGON Z((653467.7 6840811 81.5 ...))

Here is my code when I try to create a geometry column before the conversion to GeoDataFrame

bat['BAT_COORD']=bat['BAT_COORD'].apply(wkt.loads)

and the error :

Traceback (most recent call last):
  File "cleanshp.py", line 34, in <module>
    bat['BAT_COORD']=bat['BAT_COORD'].apply(wkt.loads)
  File "/home/windmyroof/.local/lib/python3.7/site-packages/pandas/core/series.py", line 4200, in apply
    mapped = lib.map_infer(values, f, convert=convert_dtype)
  File "pandas/_libs/lib.pyx", line 2388, in pandas._libs.lib.map_infer
  File "/home/windmyroof/.local/lib/python3.7/site-packages/shapely/wkt.py", line 10, in loads
    return geos.WKTReader(geos.lgeos).read(data)
  File "/home/windmyroof/.local/lib/python3.7/site-packages/shapely/geos.py", line 279, in read
    raise TypeError("Only str is accepted.")
TypeError: Only str is accepted.

The code with the shapefile import as a geodataframe (seems good), and an attempt of export shapefile (that fails) :

import geopandas as gpd
import pandas as pd
from shapely.ops import unary_union
from shapely.geometry import Point, Polygon
from shapely import wkt

def import_shapefile(path):
    # import shapefile using geopandas
    sjer_plot_locations = gpd.read_file(path)

    # create right dataset for geometry reconstruction
    columns = ['BAT_ID', 'BAT_COORD', 'BAT_HAUTEUR', 'Z_SOL']
    bat = gpd.GeoDataFrame(index=range(len(sjer_plot_locations.geometry[:])), columns=columns)

    for i in range(len(sjer_plot_locations.geometry[:])):
        bat.at[i, 'BAT_ID'] = sjer_plot_locations.ID[i]
        bat.at[i, 'BAT_HAUTEUR'] = sjer_plot_locations.HAUTEUR[i]
        bat.at[i, 'Z_SOL'] = sjer_plot_locations.Z_MIN_SOL[i]
        bat.at[i, 'BAT_COORD'] = sjer_plot_locations.geometry[i]

    return bat, sjer_plot_locations

bat, sjer = import_shapefile('/home/windmyroof/salome_shp/bats.shp')

n_bats = [i for i in range(len(bat.index))]

# cleaning geometry
# u = unary_union([bat.at[i, 'BAT_COORD'] for i in range(len(bat.index)) if i in n_bats])
# u = u.simplify(0.5)

bat.to_file('/home/windmyroof/salome_shp/bats_cleaned.shp')

And the error :

Traceback (most recent call last):
  File "cleanshp.py", line 33, in <module>
    bat.to_file('/home/windmyroof/salome_shp/bats_cleaned.shp')
  File "/home/windmyroof/.local/lib/python3.7/site-packages/geopandas/geodataframe.py", line 746, in to_file
    _to_file(self, filename, driver, schema, index, **kwargs)
  File "/home/windmyroof/.local/lib/python3.7/site-packages/geopandas/io/file.py", line 239, in _to_file
    schema = infer_schema(df)
  File "/home/windmyroof/.local/lib/python3.7/site-packages/geopandas/io/file.py", line 299, in infer_schema
    geom_types = _geometry_types(df)
  File "/home/windmyroof/.local/lib/python3.7/site-packages/geopandas/io/file.py", line 316, in _geometry_types
    geom_types_2D = df[~df.geometry.has_z].geometry.geom_type.unique()
  File "/home/windmyroof/.local/lib/python3.7/site-packages/pandas/core/generic.py", line 5130, in __getattr__
    return object.__getattribute__(self, name)
  File "/home/windmyroof/.local/lib/python3.7/site-packages/geopandas/geodataframe.py", line 173, in _get_geometry
    " column '%s'.)" % self._geometry_column_name
AttributeError: No geometry data set yet (expected in column 'geometry'.)

I fixed the problem using the comments. It was necessary to rename the column ‘BAT_COORD’ to ‘geometry’. Indeed importing directly in gdp and not pd works very well.

bat.set_geometry('BAT_COORD', inplace=True)