bigframes.bigquery.st_length#

bigframes.bigquery.st_length(series: Series | GeoSeries, *, use_spheroid: bool = False) → Series[source]#

Returns the total length in meters of the lines in the input GEOGRAPHY.

If a series element is a point or a polygon, returns zero for that row. If a series element is a collection, returns the length of the lines in the collection; if the collection doesnt contain lines, returns zero.

The optional use_spheroid parameter determines how this function measures distance. If use_spheroid is FALSE, the function measures distance on the surface of a perfect sphere.

The use_spheroid parameter currently only supports the value FALSE. The default value of use_spheroid is FALSE. See: https://cloud.google.com/bigquery/docs/reference/standard-sql/geography_functions#st_length

Examples:

>>> import bigframes.geopandas
>>> import bigframes.pandas as bpd
>>> import bigframes.bigquery as bbq

>>> from shapely.geometry import Polygon, LineString, Point, GeometryCollection

>>> series = bigframes.geopandas.GeoSeries(
...         [
...             LineString([(0, 0), (1, 0)]),  # Length will be approx 1 degree in meters
...             Polygon([(0.0, 0.0), (0.1, 0.1), (0.0, 0.1)]), # Length is 0
...             Point(0, 1),  # Length is 0
...             GeometryCollection([LineString([(0,0),(0,1)]), Point(1,1)]) # Length of LineString only
...         ]
... )

>>> result = bbq.st_length(series)
>>> result
0    111195.101177
1              0.0
2              0.0
3    111195.101177
dtype: Float64

Parameters:

• series (bigframes.series.Series | bigframes.geopandas.GeoSeries) A series containing geography objects.

• use_spheroid (bool, optional) Determines how this function measures distance. If FALSE (default), measures distance on a perfect sphere. Currently, only FALSE is supported.

Returns:

Series of floats representing the lengths in meters.

Return type:

bigframes.series.Series