Line and polygon intersection in GeoPandas/Python

Question

I am trying to intersect two GeoPandas data frames, the first one is the street data (streets) and the second one is a buffer (polygon) around a point (buffer). I want to find the intersection of streets in this buffer zone and if a street extends outside of the buffer I want it to be cut on the border. I can do the following:

streets_in_buffer=geopandas.sjoin(streets,buffer,how='inner', op='intersects')

However, I cannot cut the street (in red) at the border of the buffer (in blue) and it extends outside of the boundary like this:

I was wondering if there is a way to only get the portion of the streets inside the circle and end up with something like this:

Answer 1

As stated in the description of geopandas.overlay:

Perform spatial overlay between two polygons.

And in your problem there is one polygon (buffer) and many linestrings (streets)

1) A first solution is to iterate over the streets geometries and compute the intersections with the buffer polygon or directly use unary_union ((Shapely unary_union) to intersect one shapely geometry with other, but the result is a shapely geometry (not a GeoDataFrame)

lines = streets.geometry.unary_union
intersection = lines.intersection(buffer.geometry[0])
type(intersection)
<class 'shapely.geometry.multilinestring.MultiLineString'>
# create a GeoDataFrame
result = geopandas.GeoDataFrame({'geometry':intersection})

It is possible to do it directly:

result = geopandas.GeoDataFrame(geometry=list(streets.unary_union.intersection(buffer.unary_union)))
print(result.head(2))
             geometry
0  LINESTRING (191.0345140167503 -88.977418522730...
1  LINESTRING (141.9720460135291 -210.61516114749...

2) A second solution is to use the function clip_shp() of earthpy.clip and the result is directly a GeoDataFrame (with the original attributes)

from earthpy import clip as cl
result = cl.clip_shp(streets, buffer)
type(result)
<class 'geopandas.geodataframe.GeoDataFrame'>
print(result.head(2))
   id                    geometry
1   2  LINESTRING (141.9720460135291 -210.61516114749...
0   1  LINESTRING (191.0345140167503 -88.977418522730...

PS

sjoin (geopanda.sjoin(streets, buffer, how='left', op='intersects') gives only the left geometry (or the right geometry) and not the geometry of the intersections.