- geopandas.sjoin_nearest(left_df: GeoDataFrame, right_df: GeoDataFrame, how: str = 'inner', max_distance: Optional[float] = None, lsuffix: str = 'left', rsuffix: str = 'right', distance_col: Optional[str] = None) GeoDataFrame #
Spatial join of two GeoDataFrames based on the distance between their geometries.
Results will include multiple output records for a single input record where there are multiple equidistant nearest or intersected neighbors.
Distance is calculated in CRS units and can be returned using the distance_col parameter.
See the User Guide page https://geopandas.readthedocs.io/en/latest/docs/user_guide/mergingdata.html for more details.
- left_df, right_dfGeoDataFrames
- howstring, default ‘inner’
The type of join:
‘left’: use keys from left_df; retain only left_df geometry column
‘right’: use keys from right_df; retain only right_df geometry column
‘inner’: use intersection of keys from both dfs; retain only left_df geometry column
- max_distancefloat, default None
Maximum distance within which to query for nearest geometry. Must be greater than 0. The max_distance used to search for nearest items in the tree may have a significant impact on performance by reducing the number of input geometries that are evaluated for nearest items in the tree.
- lsuffixstring, default ‘left’
Suffix to apply to overlapping column names (left GeoDataFrame).
- rsuffixstring, default ‘right’
Suffix to apply to overlapping column names (right GeoDataFrame).
- distance_colstring, default None
If set, save the distances computed between matching geometries under a column of this name in the joined GeoDataFrame.
Since this join relies on distances, results will be inaccurate if your geometries are in a geographic CRS.
Every operation in GeoPandas is planar, i.e. the potential third dimension is not taken into account.
>>> countries = geopandas.read_file(geopandas.datasets.get_path("naturalearth_lowres")) >>> cities = geopandas.read_file(geopandas.datasets.get_path("naturalearth_cities")) >>> countries.head(2).name pop_est continent name iso_a3 gdp_md_est geometry 0 920938 Oceania Fiji FJI 8374.0 MULTIPOLYGON (((180.00000 -16.06713, 180.00000... 1 53950935 Africa Tanzania TZA 150600.0 POLYGON ((33.90371 -0.95000, 34.07262 -1.05982... >>> cities.head(2).name name geometry 0 Vatican City POINT (12.45339 41.90328) 1 San Marino POINT (12.44177 43.93610)
>>> cities_w_country_data = geopandas.sjoin_nearest(cities, countries) >>> cities_w_country_data[['name_left', 'name_right']].head(2) name_left geometry index_right pop_est continent name_right iso_a3 gdp_md_est 0 Vatican City POINT (12.45339 41.90328) 141 62137802 Europe Italy ITA 2221000.0 1 San Marino POINT (12.44177 43.93610) 141 62137802 Europe Italy ITA 2221000.0
To include the distances:
>>> cities_w_country_data = geopandas.sjoin_nearest(cities, countries, distance_col="distances") >>> cities_w_country_data[["name_left", "name_right", "distances"]].head(2) name_left name_right distances 0 Vatican City Italy 0.0 1 San Marino Italy 0.0
In the following example, we get multiple cities for Italy because all results are equidistant (in this case zero because they intersect). In fact, we get 3 results in total:
>>> countries_w_city_data = geopandas.sjoin_nearest(cities, countries, distance_col="distances", how="right") >>> italy_results = countries_w_city_data[countries_w_city_data["name_left"] == "Italy"] >>> italy_results name_x name_y 141 Vatican City Italy 141 San Marino Italy 141 Rome Italy