Extracting latitude and longitude pairs as list from LineString in GeoPandas

Question

I have a GeoPandas GeoDataFrame that looks like this:

shape_id    geometry
1000252     LINESTRING (4.91790 52.34725, 4.91797 52.34715...
1000254     LINESTRING (4.80382 52.34495, 4.80413 52.34500...
1000255     LINESTRING (4.89922 52.37811, 4.89923 52.37807...

I would like to extract the coordinates in the geometry column for each shape_id row individually as a list. For example, the output for shape_id = 1000252 should be as follows:

[[52.34725, 4.91790],
 [52.34715, 4.91797],
 [52.34742, 4.91723],
 [52.34752, 4.91713]]

What is the most efficient way to achieve this?

Answer 1

Maybe not "most efficient" but it will get you the result you want:

import geopandas as gpd

df = gpd.read_file(r'/home/bera/Drives/Lagring/GISdata/OpenStreetmap/sweden-latest-free.shp/gis_osm_railways_free_1.shp')

def f(frame):
    xy = frame.geometry.xy
    longs = xy[0].tolist()
    lats = xy[1].tolist()
    return [list(z) for z in zip(lats, longs)]

df['coords'] = df.apply(f, axis=1)

1 second for 25000 features

Answer 2

You can use this one-liner if you are happy with a list of tuples instead of a list of lists:

df['coords'] = df.geometry.apply(lambda geom: list(geom.coords))

Answer 3

Another option is to use the .mapping() method.

import geopandas as gpd
from shapely.geometry import LineString, mapping

d = {
    'id': [1, 2],
    'geometry': [
         LineString([
             (350630.319649, 5333438.389906),
             (410389.192817, 5298093.202727),
             (466139.848883, 5303194.569949),
             (500391.885943, 5310482.237409),
             (522254.888322, 5300643.886338),
             (547761.72443, 5287890.468284),
             (594038.412798, 5288254.851657),
             (620638.399026, 5307931.553798),
             (643230.16815, 5355301.392285)
             ]),
         LineString([
             (465059.389802, 5337643.246403),
             (428840.7437, 5395427.193238)]
             )]
    }

gdf = gpd.GeoDataFrame(d, crs="EPSG:25832")

def line_to_coords(geom):
    m = mapping(geom)
    list_of_tuples = m['coordinates'] # alternative -> geom.coords[:]
    list_of_lists = list(map(list, list_of_tuples))
    return list_of_lists

gdf['coords'] = gdf.apply(lambda row: line_to_coords(row.geometry), axis=1)

print(gdf)

The above code will result in:

   id  ...                                             coords
0   1  ...  [[350630.319649, 5333438.389906], [410389.1928...
1   2  ...  [[465059.389802, 5337643.246403], [428840.7437...

[2 rows x 3 columns]