nautical tracker (open and parse file)

nautical_tracker.py

import math
import argparse
import itertools
import statistics

COORDINATE_INDEX = 1
SPEED_INDEX = 3

parser = argparse.ArgumentParser(description='Nautical Tracker')
parser.add_argument('-f', '--filename', required=True, type=str, help='path to file')

def calculate_distance_between(x, y):
    (latitude_x, longitude_x) = x
    (latitude_y, longitude_y) = y

    delta_latitude = latitude_y - latitude_x
    latitude_mean = (latitude_x + latitude_y) / 2
    delta_longitude = longitude_y - longitude_x
    ap = delta_longitude * math.cos(math.radians(latitude_mean))

    return 60 * math.sqrt(delta_latitude ** 2 + ap **2)

def parse_content(record):
    fields = record.split(',')
    return list([
        int(fields[0]), # time in seconds
        (float(fields[1]), float(fields[2])), # coordinates in degrees (latitude, longitude)
        float(fields[3]), # route in degrees
        float(fields[4]), # speed in knots
    ])

def main(filename):
    with open(filename) as f:
        content = f.read().splitlines()

    records = list(map(parse_content, content))

    distance = 0
    for x, y in zip(records, records[1:]):
        distance += calculate_distance_between(x[COORDINATE_INDEX], y[COORDINATE_INDEX])

    print('Cálculo da distância percorrida pelo navio: {}'.format(distance))

    speeds = list(map(lambda record: record[SPEED_INDEX], records))
    speed_mean = statistics.mean(speeds)

    print('Cálculo da velocidade média da viagem: {}'.format(speed_mean))

if __name__ == '__main__':
    args = parser.parse_args()
    main(args.filename)

Nao otimizado para fins didaticos.