BUG: 'GeometryArray' object has no attribute 'value_counts'

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

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Code Sample, a copy-pastable example

gdf["geometry"].value_counts()

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-25-fb6329993e01> in <module>
----> 1 gdf["geometry"].value_counts()

C:\tools\miniconda3\envs\project-dev\lib\site-packages\pandas\core\base.py in value_counts(self, normalize, sort, ascending, bins, dropna)
   1243         dtype: int64
   1244         """
-> 1245         result = value_counts(
   1246             self,
   1247             sort=sort,

C:\tools\miniconda3\envs\project-dev\lib\site-packages\pandas\core\algorithms.py in value_counts(values, sort, ascending, normalize, bins, dropna)
    790 
    791             # handle Categorical and sparse,
--> 792             result = Series(values)._values.value_counts(dropna=dropna)
    793             result.name = name
    794             counts = result._values

AttributeError: 'GeometryArray' object has no attribute 'value_counts'

Problem description

The “geometry” columns of a geopandas data frame should act like a regular pandas Series. This includes supporting “value_counts”.

I can’t even monkey-patch it with something that uses collections.Counter since the geometry types are unhashable, i.e. the following also fails:

import collections
pd.Series(collections.Counter(gdf["geometry"]), name="geometry")

Expected Output

Same as pd.Series.value_counts(*args, **kwargs)

Output of geopandas.show_versions()

SYSTEM INFO

python : 3.8.6 | packaged by conda-forge | (default, Nov 27 2020, 18:58:29) [MSC v.1916 64 bit (AMD64)] executable : C:\tools\miniconda3\envs\project-dev\python.exe machine : Windows-10-10.0.18362-SP0

GEOS, GDAL, PROJ INFO

GEOS : None GEOS lib : None GDAL : 3.1.4 GDAL data dir: None PROJ : 7.1.1 PROJ data dir: C:\tools\miniconda3\envs\project-dev\Library\share\proj

PYTHON DEPENDENCIES

geopandas : 0.8.1 pandas : 1.1.5 fiona : 1.8.18 numpy : 1.19.4 shapely : 1.7.1 rtree : 0.9.4 pyproj : 2.6.1.post1 matplotlib : 3.3.3 mapclassify: 2.3.0 geopy : 2.0.0 psycopg2 : None geoalchemy2: None pyarrow : 2.0.0

[m-richards]

I think I’ll work on this as well, seems pretty straightforward and nice to have.

[jorisvandenbossche]

Would it be simple to do something like convert the geometry series to into a regular pandas binary series using WKB, then use regular value_counts and then convert the index back to a geometry type?

Yes, that would be the idea. Something like this (untested code), method on GeometryArray:

def value_counts(self, ...):
    values = to_wkb(self)
    from pandas import Series, Index
    result = Series(values).value_counts(...)
    result.index = Index(from_wkb(result.index))