DOC: Add example in GeoDataFrame docstring (#1456)
DOC: Add example in GeoDataFrame docstring (#1456)

* add example in GeoDataFrame docstring

* Update GeoDataFrame docstring

Co-authored-by: Martin Fleischmann <54669547a225ff20cba8b75a4adca540eef25858@martinfleischmann.net>

Co-authored-by: Martin Fleischmann <54669547a225ff20cba8b75a4adca540eef25858@martinfleischmann.net>
jdmcbr/geopandas,geopandas/geopandas,jdmcbr/geopandas,jorisvandenbossche/geopandas,jorisvandenbossche/geopandas,geopandas/geopandas,geopandas/geopandas,jorisvandenbossche/geopandas