BUG: iloc indexing Dataframe with only one column (`geometry`) raises TypeError

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of geopandas.

• (optional) I have confirmed this bug exists on the master branch of geopandas.

---

Code Sample, a copy-pastable example

from shapely.geometry import Polygon
from geopandas import GeoSeries, GeoDataFrame

polys = GeoSeries(
    [
        Polygon([(0, 0), (2, 0), (2, 2), (0, 2)]),
        Polygon([(1, 1), (3, 1), (3, 3), (1, 3)]),
    ]
)

gdf = GeoDataFrame({"geometry": polys, "number": range(len(polys))})
gdf.iloc[[0]] = gdf.iloc[[1]]  # works

gdf = GeoDataFrame({"geometry": polys})
gdf.iloc[[0]] = gdf.iloc[[1]]  # does not work

Problem description

One may not always have other columns than geometry when wanting to use .iloc

Example of code where I first encountered this issue:

from shapely.geometry import Polygon
from geopandas import GeoSeries, GeoDataFrame, overlay

polys = GeoSeries(
    [
        Polygon([(0, 0), (2, 0), (2, 2), (0, 2)]),
        Polygon([(1, 1), (3, 1), (3, 3), (1, 3)]),
        Polygon([(2, 2), (4, 2), (4, 4), (2, 4)]),
    ]
)

gdf = GeoDataFrame({"geometry": polys})

for i in range(0, len(gdf) - 1):
    gdf.iloc[[i]] = overlay(gdf.iloc[[i]], gdf.iloc[[i + 1]], how="difference")

Expected Output

No TypeError.

Output of geopandas.show_versions()

Failed CDLL(libgeos_c.so.1) Failed CDLL(libgeos_c.so)

SYSTEM INFO

python : 3.9.5 (default, May 11 2021, 08:20:37) [GCC 10.3.0] executable : /home/username/Documents/project_name/env/bin/python machine : Linux-5.11.0-18-generic-x86_64-with-glibc2.33

GEOS, GDAL, PROJ INFO

GEOS : None GEOS lib : None GDAL : 3.3.0 GDAL data dir: /home/username/Documents/project_name/env/lib/python3.9/site-packages/fiona/gdal_data PROJ : 8.0.1 PROJ data dir: /home/username/Documents/project_name/env/lib/python3.9/site-packages/pyproj/proj_dir/share/proj

PYTHON DEPENDENCIES

geopandas : 0.9.0 pandas : 1.2.4 fiona : 1.8.20 numpy : 1.20.3 shapely : 1.7.1 rtree : 0.9.7 pyproj : 3.1.0 matplotlib : 3.4.2 mapclassify: None geopy : 2.1.0 psycopg2 : None geoalchemy2: None pyarrow : None pygeos : None

[martinfleis]

Thanks for the report! I can confirm that this is a bug in the way how GeometryArray handles gdf (it does not 😃).

I think we need to add one more condition handling this situation here: https://github.com/geopandas/geopandas/blob/cb88dd4a9100bb990f6eb9b286e1ef3a0b185e3c/geopandas/array.py#L371

Would you like to try to fix it?

[Akylzhan]

@JoakimJoensuu, do you plan to work on this issue? If no, I want to try to fix