Lat/Long Distance

_problem.md

I'm having an issue with assignment 3:

for the coordinates (41.721194054071, -73.934258235003) & (33.7199, -116.232), which a the first coordinates used in the test file, my script returns ~ 2353 mi. As far as I can tell that's correct.

Unfortunately, testtour.py seems to be expecting ~ 4705 mi for the first test.

2352.731305 != 4705.462610 ... Incorrect

I've verified that the coordinates are correct:

start_latitude = 41.721194054071
start_longitude = -73.934258235003

and from the graph

{
    id: "264100516989470",
    ...
    {
        city: "Indio",
        state: "California",
        country: "United States",
        latitude: 33.7199,
        longitude: -116.232
    },
    ...
}

distance.py

import math

def lat_long_distance(c1, c2):

    r = 3960 # miles

    degrees_to_radians = ((2 * math.pi) / 360)

    lat1 = (90.0 - c1[0]) * degrees_to_radians
    lat2 = (90.0 - c2[0]) * degrees_to_radians

    long1 = c1[1] * degrees_to_radians
    long2 = c2[1] * degrees_to_radians

    cos = (math.sin(lat1) * math.sin(lat2) * math.cos(long1 - long2) + 
           math.cos(lat1) * math.cos(lat2))

    arc = math.acos( cos )
    res = arc * r

    return res

def main():
    c1 = (41.721194054071, -73.934258235003)
    c2 = (33.7199, -116.232)
    print c1
    print c2
    print str(lat_long_distance(c1, c2)) + ' miles'

if __name__ == '__main__':
    main()

output.txt

(41.721194054071, -73.934258235003)
(33.7199, -116.232)
2352.73130502 miles