Can't Form DataFrame from Parallel Offset Output

Question

I've been developing code to take a .csv with lat-long coords and convert them to LineStrings before creating parallel offsets for them. This has been working so far, but yesterday after clearing my variables, I started running into an error when running my code.

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

df = pd.read_csv("***/Kingsboro Rd NE.csv")
df = df.drop_duplicates()

geometry = [Point(xy) for xy in zip(df.lng, df.lat)]
df['geometry'] = geometry
df['agg'] = 1
df_line = gpd.GeoDataFrame(df.groupby(['agg'])['geometry'].apply(lambda x: LineString(x.tolist())), geometry='geometry')
df_line = df_line.set_crs("EPSG:4326")
df_line = df_line.to_crs("EPSG:2240")

df_offset_l = pd.DataFrame(df_line.iloc[0].geometry.parallel_offset(25, 'left', 2, mitre_limit = 100.0))

Everything runs fine until the final line, for which I get the following error:

ValueError: DataFrame constructor not properly called!

As I mentioned before, I have not been getting this error until yesterday, and I need it to work properly to perform the other data manipulation steps following this line of code.

Here's a sample of the input file:

lat	long
33.85556214	-84.35139656
33.85569133	-84.35140193
33.85556214	-84.35139656
33.85553986	-84.35136706
33.85550868	-84.35134828

Answer 1

DataFrame or GeoDataFrame needs an iterable parameter but you pass shapely object (LineString) to it. So you get that error.

Make offset line:

offset_line = df_line.iloc[0].geometry.parallel_offset(25, 'left', 2, mitre_limit = 100.0)

Then,

• If you need a DataFrame use this way:

  df_offset_l = pd.DataFrame({"geometry": [offset_line]})
  
  # OUTPUT (DataFrame)
  #     geometry
  # 0   LINESTRING (2240477.867 1402553.588, 2240476.3...
  

• If you need a GeoDataFrame use this way:

  df_offset_l = gpd.GeoDataFrame({"geometry": [offset_line]})
  
  # OUTPUT (GeoDataFrame)
  #     geometry
  # 0   LINESTRING (2240477.866711137 1402553.58829784...