Distance calculation between two latitude and longitude points with python (using spherical trigonometry)

import math


def get_distance_m(lat1, lon1, lat2, lon2):
    """
Distance between two points(m)
Simple distance calculation using spherical trigonometry
Google Map API geometory.computeDistanceBetween logic
    https://www.suzu6.net/posts/167-php-spherical-trigonometry/
    """
    R = 6378137.0  #Equatorial radius
    lat1 = math.radians(lat1)
    lon1 = math.radians(lon1)
    lat2 = math.radians(lat2)
    lon2 = math.radians(lon2)
    diff_lon = lon1 - lon2
    dist = math.sin(lat1) * math.sin(lat2) + math.cos(lat1) * math.cos(lat2) * math.cos(diff_lon)
    return R * math.acos(min(max(dist, -1.0), 1.0))


if __name__ == "__main__":
    #Calculate the distance when moving 1 arcsecond in the latitude and longitude directions
    distance = get_distance_m(lon1=139.0,
                              lat1=35.0,
                              lon2=139.0 + 1.0 / 3600.0,
                              lat2=35.0 + 1.0 / 3600.0)
    print(distance)

Execution result

39.972442531744505