Python Practice: Distance Between Points

Below is a function that will calculate the sortest distance between any two points on the Earth’s surface. Do not worry about how it works. It is simply a tool for this exercise.:

def calculate_distance(point1, point2):
    """
    Calculate the distance (in miles) between point1 and point2.
    point1 and point2 must have the format [latitude, longitude].
    The return value is a float.

    Modified and converted to Python from: http://www.movable-type.co.uk/scripts/latlong.html
    """
    import math

    def convert_to_radians(degrees):
        return degrees * math.pi / 180

    radius_earth = 6.371E3 # km
    phi1 = convert_to_radians(point1[0])
    phi2 = convert_to_radians(point2[0])
    delta_phi = convert_to_radians(point1[0] - point2[0])
    delta_lam = convert_to_radians(point1[1] - point2[1])

    a = math.sin(0.5 * delta_phi)**2 + math.cos(phi1) * math.sin(0.5 * delta_lam)**2
    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))
    return radius_earth * c / 1.60934 # convert km to miles

The JSON file at this URL contains some cities with international airports, each with a latitude, a longitude, and a city that it connects to. For the curious, the list of airports comes from Wikipedia.

Write a function that,

• given a starting city and an ending city, will return a path between the two cities (including the two cities).
• also returns the total distance traveled between cities.
• appropriately handles the situation where no path exists.

Stretch Goals

Try to incorporate any (or all) of these. They are/can be independent of each other.

• Add to your function a parameter that makes it return the shortest path (lowest distance) between the two cities.
• Add to your function a parameter that makes it return the path with the fewest stops between the two cities.
• Have your function take a parameter for a limit to the distance between any two cities. If specified, your function returns a path where each city-to-city jump is less than or equal to that limit.

Submitting Your Work

Create a flight-paths branch in your code-katas repository. Add this function in a script to your flight-paths branch.

The tests that demonstrate your code works should be in a test_flight_paths.py file. Add documentation about your code in the repo’s README.md. Make sure to add notes about and resources or collaborators you worked with in solving this problem.

After you’ve added your code solution into GitHub, send a pull request to your master branch. Submit the link to that pull request to Canvas.

Use the comment box in Canvas to add any questions, comments or reflections on this assignment and your approach to it.