geodesy.haversine_distance

Attributes

EARTH_RADIUS

Functions

haversine_distance(→ float)

Calculate great-circle distance between two points on a sphere,

Module Contents

geodesy.haversine_distance.haversine_distance(lat1: float, lon1: float, lat2: float, lon2: float) → float

Calculate great-circle distance between two points on a sphere, given longitudes and latitudes https://en.wikipedia.org/wiki/Haversine_formula

We know that the globe is “sort of” spherical, so a path between two points isn’t exactly a straight line. We need to account for the Earth’s curvature when calculating distance from point A to B. This effect is negligible for small distances but adds up as distance increases. The Haversine method treats the Earth as a sphere, which allows us to “project” the two points A and B onto the surface of that sphere and approximate the spherical distance between them. Since the Earth is not a perfect sphere, other methods which model the Earth’s ellipsoidal nature are more accurate, but a quick and modifiable computation like Haversine can be handy for shorter-range distances.

Args:

lat1: latitude of coordinate 1 in degrees lon1: longitude of coordinate 1 in degrees lat2: latitude of coordinate 2 in degrees lon2: longitude of coordinate 2 in degrees

Returns:

geographical distance between two points in metres

>>> from collections import namedtuple
>>> point_2d = namedtuple("point_2d", "lat lon")
>>> SAN_FRANCISCO = point_2d(37.774856, -122.424227)
>>> YOSEMITE = point_2d(37.864742, -119.537521)
>>> f"{haversine_distance(*SAN_FRANCISCO, *YOSEMITE):0,.0f} meters"
'253,748 meters'
>>> NEW_YORK = point_2d(40.712776, -74.005974)
>>> LOS_ANGELES = point_2d(34.052235, -118.243683)
>>> f"{haversine_distance(*NEW_YORK, *LOS_ANGELES):0,.0f} meters"
'3,935,746 meters'
>>> LONDON = point_2d(51.507351, -0.127758)
>>> PARIS = point_2d(48.856614, 2.352222)
>>> f"{haversine_distance(*LONDON, *PARIS):0,.0f} meters"
'343,549 meters'
>>> haversine_distance(0, 0, 0, 0)
0.0
>>> from math import isclose
>>> quarter_equator = haversine_distance(0, 0, 0, 90)
>>> isclose(quarter_equator, 10_007_543, rel_tol=1e-3)
True

geodesy.haversine_distance.EARTH_RADIUS = 6371000