Converting Pandas DataFrame to GeoDataFrame
Convert the DataFrame's content (e.g. Lat
and Lon
columns) into appropriate Shapely geometries first and then use them together with the original DataFrame to create a GeoDataFrame.
from geopandas import GeoDataFrame
from shapely.geometry import Point
geometry = [Point(xy) for xy in zip(df.Lon, df.Lat)]
df = df.drop(['Lon', 'Lat'], axis=1)
gdf = GeoDataFrame(df, crs="EPSG:4326", geometry=geometry)
Result:
Date/Time ID geometry
0 4/1/2014 0:11:00 140 POINT (-73.95489999999999 40.769)
1 4/1/2014 0:17:00 NaN POINT (-74.03449999999999 40.7267)
Since the geometries often come in the WKT format, I thought I'd include an example for that case as well:
import geopandas as gpd
import shapely.wkt
geometry = df['wktcolumn'].map(shapely.wkt.loads)
df = df.drop('wktcolumn', axis=1)
gdf = gpd.GeoDataFrame(df, crs="EPSG:4326", geometry=geometry)
Update 201912: The official documentation at https://geopandas.readthedocs.io/en/latest/gallery/create_geopandas_from_pandas.html does it succinctly using geopandas.points_from_xy
like so:
gdf = geopandas.GeoDataFrame(
df, geometry=geopandas.points_from_xy(x=df.Longitude, y=df.Latitude)
)
You can also set a crs
or z
(e.g. elevation) value if you want.
Old Method: Using shapely
One-liners! Plus some performance pointers for big-data people.
Given a pandas.DataFrame
that has x Longitude and y Latitude like so:
df.head()
x y
0 229.617902 -73.133816
1 229.611157 -73.141299
2 229.609825 -73.142795
3 229.607159 -73.145782
4 229.605825 -73.147274
Let's convert the pandas.DataFrame
into a geopandas.GeoDataFrame
as follows:
Library imports and shapely speedups:
import geopandas as gpd
import shapely
shapely.speedups.enable() # enabled by default from version 1.6.0
Code + benchmark times on a test dataset I have lying around:
#Martin's original version:
#%timeit 1.87 s ± 7.03 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
gdf = gpd.GeoDataFrame(df.drop(['x', 'y'], axis=1),
crs={'init': 'epsg:4326'},
geometry=[shapely.geometry.Point(xy) for xy in zip(df.x, df.y)])
#Pandas apply method
#%timeit 8.59 s ± 60.6 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
gdf = gpd.GeoDataFrame(df.drop(['x', 'y'], axis=1),
crs={'init': 'epsg:4326'},
geometry=df.apply(lambda row: shapely.geometry.Point((row.x, row.y)), axis=1))
Using pandas.apply
is surprisingly slower, but may be a better fit for some other workflows (e.g. on bigger datasets using dask library):
Credits to:
- Making shapefile from Pandas dataframe? (for the pandas apply method)
- Speed up row-wise point in polygon with Geopandas (for the speedup hint)
Some Work-In-Progress references (as of 2017) for handling big dask
datasets:
- http://matthewrocklin.com/blog/work/2017/09/21/accelerating-geopandas-1
- https://github.com/geopandas/geopandas/issues/461
- https://github.com/mrocklin/dask-geopandas