flatten geometry series (3D to 2D) in geopandas dataframe

geopandas_convert_geometry_3D_2D.py

# Often when reading in a ShapeFile from Basemap, you'll get: "ValueError: readshapefile can only handle 2D shape types"
# A trick can be to convert your geometry in your GeoPandas Dataframe and restoring the new flattened 2D geometry
# series back into a shapefile and try again.

# edit from http://stackoverflow.com/questions/33417764/basemap-readshapefile-valueerror  

from shapely.geometry import Polygon, MultiPolygon, shape, Point
import geopandas as gp
def convert_3D_2D(geometry):
    '''
    Takes a GeoSeries of 3D Multi/Polygons (has_z) and returns a list of 2D Multi/Polygons
    '''
    new_geo = []
    for p in geometry:
        if p.has_z:
            if p.geom_type == 'Polygon':
                lines = [xy[:2] for xy in list(p.exterior.coords)]
                new_p = Polygon(lines)
                new_geo.append(new_p)
            elif p.geom_type == 'MultiPolygon':
                new_multi_p = []
                for ap in p:
                    lines = [xy[:2] for xy in list(ap.exterior.coords)]
                    new_p = Polygon(lines)
                    new_multi_p.append(new_p)
                new_geo.append(MultiPolygon(new_multi_p))
    return new_geo

geodf_2d = gp.GeoDataFrame.from_file(shp_file) # plug_in your shapefile
geodf_2d.geometry = convert_3D_2D(geodf_2d.geometry) # new geodf with 2D geometry series

# geodf_2d.to_file(path + shapefile.shp, driver = 'ESRI Shapefile') will sore a shapefile with 2D shape types

Thanks! works great.