Invalid geometry objects in Shapely list

Question

I have a creating a list of shapely polygons. While I am trying to create a geodataframe from that list it gives an error:

intersec_ls = [poly1, poly2, poly3]
cu = cascaded_union(intersec_ls)
differ = buffer.difference(cu)

fin_ls.append(differ)
fin_ls.append(intersec_ls)

geom = gpd.GeoSeries(fin_ls)
gdf = gdf( geometry= geom)

TypeError: Input must be valid geometry objects: [<shapely.geometry.polygon.Polygon object at 0x00000213702BEDA0>]

How can I deal with invalid geometry in the list?

Answer 1

There are two mistakes in your script.

1. Since intersect_ls is a list, use extend instead of append. The reason of getting error is that. Because the first item in fin_ls is a geometry, the other is a list, but it should have been a geometry too.

    fin_ls.append(differ)
    fin_ls.extend(intersec_ls)
   

2. Since gdf is a GeoDataFrame instance, you cannot use parenthesis with gdf as in gdf( geometry= geom). Instead, use

    gdf = gpd.GeoDataFrame(gdf, geometry=geom) 
   

Or just use gdf = gpd.GeoDataFrame(geometry=geom) if you didn't define gdf before. In this case gdf includes only geometries.