lab_weather/weather/weather_apis.py

86 lines
3.2 KiB
Python

# weather_apis.py
# ---------------
# By MWC Contributors
#
# This module contains functions which interact with external APIs related to weather.
# The module relies on USA-specific services; it will need to be extended using local
# services for other regions.
# The National Weather Service (NWS) provides weather forecasting services across US
# states and territories. NWS divides the country into a grid of 2.5km squares, and
# provides a forecast for each grid square.
#
# You will need to use these functions, but you don't need to edit this file.
import geocoder
import requests
def geocode_location(location_string):
"""Translates a location string into latitude and longitude coordinates.
Uses the OpenStreetMap API. Returns a dict with keys 'lat' and 'lng'
as shown below. When no result is found, returns None.
>>> geocode_location('11 Wall Street, New York')
{"lat": -74.010865, "lng": 40.7071407}
"""
result = geocoder.osm(location_string)
if result:
lat, lng = result.latlng
return {'lat': lat, 'lng': lng}
def estimate_location(ip_address=None):
"""Estimates a location based on the request's IP address, returning
latitude and longitude coodrdinates. When no IP address is provided,
uses the user's current IP address.
>>> geocode_ip_address()
{'lat': 23.6585116, 'lng': -102.0077097}
"""
result = geocoder.ip(ip_address or 'me')
if result:
lat, lng = result.latlng
return {'lat': lat, 'lng': lng}
def get_weather_office(lat, lng):
"""Looks up the NWS weather office for a pair of lat/lng coordinates.
Returns a dict containing keys 'office', 'x', and 'y'.
If no matching weather office is found, returns None.
>>> coords = geocode_ip_address()
>>> get_weather_office(coords['lat'], coords['lng'])
{'office': 'BUF', 'x': 39, 'y': 59}
"""
url = "https://api.weather.gov/points/{},{}".format(lat, lng)
response = requests.get(url)
if response.ok:
result = response.json()
return {
"office": result['properties']['gridId'],
"x": result['properties']['gridX'],
'y': result['properties']['gridY']
}
def get_forecast(office, x, y, metric=False):
"""Fetches the weather forecast for the given NWS office, and (x, y) NWS grid tile.
Returns a list of time periods, where each time period is a dict containing keys
as shown below. If no forecast can be found, returns None.
When metric is True, returns temperatures in Celcius and wind speeds in km/hr.
"""
url = "https://api.weather.gov/gridpoints/{}/{},{}/forecast".format(office, x, y)
if metric:
url += "?units=si"
response = requests.get(url)
if response.ok:
result = response.json()
forecast = []
for period in result['properties']['periods']:
forecast.append({
'name': period['name'],
'temperature': period['temperature'],
'wind_speed': period['windSpeed'],
'wind_direction': period['windDirection'],
'description': period['shortForecast'],
})
return forecast