49 lines
1.5 KiB
Python
49 lines
1.5 KiB
Python
"""Module with location helpers."""
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import collections
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from math import radians, cos, sin, asin, sqrt
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import requests
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LocationInfo = collections.namedtuple(
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"LocationInfo",
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['ip', 'country_code', 'country_name', 'region_code', 'region_name',
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'city', 'zip_code', 'time_zone', 'latitude', 'longitude',
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'use_fahrenheit'])
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def detect_location_info():
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""" Detect location information. """
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try:
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raw_info = requests.get(
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'https://freegeoip.net/json/', timeout=5).json()
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except requests.RequestException:
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return
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data = {key: raw_info.get(key) for key in LocationInfo._fields}
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# From Wikipedia: Fahrenheit is used in the Bahamas, Belize,
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# the Cayman Islands, Palau, and the United States and associated
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# territories of American Samoa and the U.S. Virgin Islands
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data['use_fahrenheit'] = data['country_code'] in (
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'BS', 'BZ', 'KY', 'PW', 'US', 'AS', 'VI')
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return LocationInfo(**data)
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# From: http://stackoverflow.com/a/4913653/646416
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def distance(lon1, lat1, lon2, lat2):
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"""
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Calculate the great circle distance in meters between two points specified
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in decimal degrees on the earth using the Haversine algorithm.
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"""
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# convert decimal degrees to radians
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lon1, lat1, lon2, lat2 = (radians(val) for val in (lon1, lat1, lon2, lat2))
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dlon = lon2 - lon1
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dlat = lat2 - lat1
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angle = sin(dlat/2)**2 + cos(lat1) * cos(lat2) * sin(dlon/2)**2
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# Radius of earth in meters.
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radius = 6371000
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return 2 * radius * asin(sqrt(angle))
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