dist_tp_1.py

#!/usr/bin/python
# -*- coding: utf-8 -*-

# Distances on Globe and Flat Earth
# Instructions:
# - Input each information as asked;
# - Input coordinates in degrees (23.1234);
# - If coordinates are at South or West, use negative numbers (-23.1234);
# - North Pole to Equator based on a Flat Earth with 40.075km equatorial perimeter.
# Earth radius = 6371km rounded, so little diferences are expected if you're considering WGS84 geoid.
# Author: MrBiTs (mrbits@mrbits.com.br)
# CHUPA POMBAIADA!!!

from math import pi, sin, cos, sqrt, radians, atan2


def globe(lat1, long1, lat2, long2):
    '''Assume Earth as a sphere'''

    dlat = radians(lat2 - lat1)
    dlon = radians(long2 - long1)
    a = sin(dlat / 2) * sin(dlat / 2) + cos(radians(lat1)) * cos(radians(lat2)) * sin(dlon / 2) * sin(dlon / 2)
    c = 2 * atan2(sqrt(a), sqrt(1 - a))
    d = R * c

    return d


def flatland(lat1, long1, lat2, long2):
    pi2 = pi / 2
    lat1 = radians(lat1)
    long1 = radians(long1)
    lat2 = radians(lat2)
    long2 = radians(long2)

    r1 = (1 - lat1 / pi2) * EQ
    r2 = (1 - lat2 / pi2) * EQ
    x1 = r1 * cos(long1)
    y1 = r1 * sin(long1)
    x2 = r2 * cos(long2)
    y2 = r2 * sin(long2)
    dx = x2 - x1
    dy = y2 - y1

    return sqrt(dx**2 + dy**2)


if __name__ == "__main__":

    place = raw_input("Name your places: ")
    lat1 = raw_input("Type Latitude at first place in degrees: ")
    long1 = raw_input("Type Longitude at first place in degrees: ")
    lat2 = raw_input("Type Latitude at second place in degrees: ")
    long2 = raw_input("Type Longitude at second place in degrees: ")
    EQ = raw_input("Type North Pole to Equator in Flat Earth (or leave it blank to assume 10,007.543398km): ")

    R = 6371.0

    if not EQ:
        EQ = R * pi / 2

    LG = globe(
        float(lat1),
        float(long1),
        float(lat2),
        float(long2)
    )

    print "Distance on Globe: {0} km".format(LG)

    LF = flatland(
        float(lat1),
        float(long1),
        float(lat2),
        float(long2)
    )

    print "Distance on FE: {0} km".format(LF)