我的 geopy 大圆距离计算有什么问题？

Question

I want to compute the distance (in km) using geopy library between two points defined by their respective (lat, lon) coordinates.

My code

from geopy.distance import great_circle

# lat, lon
p1 = (45.8864, -7.2305)
p2 = (46.2045, -7.2305)

# distance in km
great_circle(p1, p2).km
>>> 35.371156132664765

To check above results, I used the tool available here: https://www.movable-type.co.uk/scripts/latlong.html but the two outputs do not match.

The output of my code is 35.371156132664765 though the above tool returns a distance of 15.41 km. How come the results are different?

Answer 1

Your calculation for the points p1 and p2 is wrong, you need to convert the minutes and seconds into degree correctly. Otherwise the code works prefectly.

Answer 2

Your arguments are flipped: geopy expects coordinates in (lon, lat) order.

p2 = (-7.2305, 46.2045)
p1 = (-7.2305, 45.8864)
great_circle(p1, p2).km
# => 35.08987842072082

(Additionally, as moreON says in comments, the web tool you have linked treats 46.2045 and 46 20 45N very differently.)