Redsnake trivia: speed of a swallow

swallow.py

import math
import string
from time import struct_time

import json
from requests import request

def get_geocoord(pt):
    '''
    Take the Web2.0y approach and get Google to do all the
    hard geocoding work for us.
    '''
    geoapi_addr = 'http://maps.googleapis.com/maps/api/geocode/json'
    geoapi_args = { 'sensor': 'false' }
    geoapi_args['address'] = pt

    response = request('GET', geoapi_addr, params=geoapi_args)
    if response.ok:
        result = json.loads(response.text)
        latlng = result['results'][0]['geometry']['location']
        return [latlng['lat'], latlng['lng']]
    else:
        print 'Aaaaaaaahhh!: ' + response


def calc_great_circle(pt1, pt2):
    '''
    Sphereical law of cosines formula
    '''
    lat1 = pt1[0]
    long1 = pt1[1]
    lat2 = pt2[0]
    long2 = pt2[0]

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

    r = 6372.8 # avg radius of Earth in km
    dist = r * math.radians(ang)
    return dist


def what_is_the_airspeed_of_a_swallow(orig, dst, t, was_laden=False):
    '''
    Takes address or lat/long for each point, and a time as a time_struct
    '''
    pt1 = get_geocoord(orig)
    pt2 = get_geocoord(dst)
    dist = calc_great_circle(pt1, pt2)

    elapsed = (t.tm_hour +
               (t.tm_min / 60.0) +
               (t.tm_sec / 3600.0))

    airspeed = dist / elapsed

    # because we know an unladen swallow's flight is at
    # least two laden swallow's flights.
    if was_laden:
        airspeed = airspeed * 2

    return 'Estimated airspeed: {0} km/h'.format(round(airspeed, 0))