calc_distance_on_unit_sphere

pyhelpers.geom.calc_distance_on_unit_sphere(pt1, pt2, unit='mile', precision=None)[source]

Calculate distance between two points.

Parameters:

  • pt1 (shapely.geometry.Point | tuple | numpy.ndarray) – one point

  • pt2 (shapely.geometry.Point | tuple | numpy.ndarray) – another point

  • unit (str) – distance unit (for output), defaults to 'miles'; valid options include 'mile' and 'km'

  • precision (None | int) – decimal places of the calculated result, defaults to None

Returns:

distance (in miles) between pt1 and pt2 (relative to the earth’s radius)

Return type:

float | None

Examples:

>>> from pyhelpers.geom import calc_distance_on_unit_sphere
>>> from pyhelpers._cache import example_dataframe

>>> example_df = example_dataframe()
>>> example_df
            Longitude   Latitude
City
London      -0.127647  51.507322
Birmingham  -1.902691  52.479699
Manchester  -2.245115  53.479489
Leeds       -1.543794  53.797418

>>> london, birmingham = example_df.loc[['London', 'Birmingham']].values
>>> london
array([-0.1276474, 51.5073219])
>>> birmingham
array([-1.9026911, 52.4796992])

>>> arc_len_in_miles = calc_distance_on_unit_sphere(london, birmingham)
>>> arc_len_in_miles  # in miles
101.10431101941569

>>> arc_len_in_miles = calc_distance_on_unit_sphere(london, birmingham, precision=4)
>>> arc_len_in_miles
101.1043

Note

This function is modified from the original code available at [GEOM-CDOUS-1]. It assumes the earth is perfectly spherical and returns the distance based on each point’s longitude and latitude.