[Swlug] Re Maths calculations

[Alan Gray]

Hello Rhys,

Jason has done an excellent analysis of the issue.

I think, though, he is wrong in thinking that it's 'o' level stuff. They 
might deal with sin, cos etc, but the analysis would be beyond most.

I also came across this on "geeksforgeeks" under "Haversine formula to 
find distance between two points on a sphere"

# Python 3 program for the
# haversine formula
import math

# Python 3 program for the
# haversine formula
def haversine(lat1, lon1, lat2, lon2):

     # distance between latitudes
     # and longitudes
     dLat = (lat2 - lat1) * math.pi / 180.0
     dLon = (lon2 - lon1) * math.pi / 180.0

     # convert to radians
     lat1 = (lat1) * math.pi / 180.0
     lat2 = (lat2) * math.pi / 180.0

     # apply formulae
     a = (pow(math.sin(dLat / 2), 2) +
          pow(math.sin(dLon / 2), 2) *
              math.cos(lat1) * math.cos(lat2));
     rad = 6371
     c = 2 * math.asin(math.sqrt(a))
     return rad * c

# Driver code
if __name__ == "__main__":
     lat1 = 51.5007
     lon1 = 0.1246
     lat2 = 40.6892
     lon2 = 74.0445

     print(haversine(lat1, lon1,lat2, lon2), "K.M.")

# This code is contributed
# by ChitraNayal


Kindest regards

Alan Gray