Geopandas buffer using geodataframe while maintaining the dataframe

Question

The objective is to create a geoDataFrame with buffered geometries AND with all the "attributes" of the original geodataframe.

I am able to perform a buffer on my geoDataFrame using:

gdfHybasBuffer = gdfHybas['geometry'].buffer(-0.005,resolution=16)

but the result is a geoSeries and not a geoDataFrame, and therefore does not contain the data from the original geoDataFrame nor does it contain an index to join the data to the original data. Is there a better way to perform a buffer while maintaining the original attribute data?

github Code

It is pretty straight forward to create a buffer on a geopandas geoSeries.

• RutgerH: I already found one error in my code: gdfHybas = gdfHybas.set_index('PFAF_ID') instead of gdfHybas.set_index('PFAF_ID'). In that case, the index will be preserved in the geoSeries and I can use merge to replace the old geometry with the new buffers
• RutgerH: The next problem I encountered when using geopandas merge, is that it does not by default merge on the indices (if you do not specify "on=")

Answer 1

from shapely.geometry import Point
import pandas as pd
import geopandas as gpd
p1 = Point((1,2))
p2 = Point((5,6))
df = pd.DataFrame({'a': [11,22]})
gdf = gpd.GeoDataFrame(df, geometry = [p1,p2])
gdf
#out: 
# a geometry
#0 11 POINT (1 2)
#1 22 POINT (5 6)

You can directly assign the buffer as a new geometry column to your GeoDataFrame:

gdf['geometry'] = gdf.geometry.buffer(2)
#out:
# a geometry
#0 11 POLYGON ((3 2, 2.990369453344394 1.80396571934...
#1 22 POLYGON ((7 6, 6.990369453344394 5.80396571934...
gdf.plot()

buffer

• user32882: This won't work if your original dataframe has null geometries
• Alz: @user32882 you cannot even create a GeoDataFrame if your input geometries are not valid
• user32882: not invalid... null geometry (empty) its not the same thing
• Alz: can you give an example?
• jesnes: @Alz Does this mean that the geopandas overlay and geometry manipulation functions are vectorized?