ordigi/elodie/geolocation.py

210 lines
6.1 KiB
Python

"""Look up geolocation information for media objects."""
from os import path
from ConfigParser import ConfigParser
import fractions
import pyexiv2
import requests
import urllib
from elodie import constants
from elodie.localstorage import Db
class Fraction(fractions.Fraction):
"""Only create Fractions from floats.
Should be compatible with Python 2.6, though untested.
>>> Fraction(0.3)
Fraction(3, 10)
>>> Fraction(1.1)
Fraction(11, 10)
"""
def __new__(cls, value, ignore=None):
return fractions.Fraction.from_float(value).limit_denominator(99999)
def coordinates_by_name(name):
# Try to get cached location first
db = Db()
cached_coordinates = db.get_location_coordinates(name)
if(cached_coordinates is not None):
return {
'latitude': cached_coordinates[0],
'longitude': cached_coordinates[1]
}
# If the name is not cached then we go ahead with an API lookup
geolocation_info = lookup(name)
if(geolocation_info is not None):
if(
'results' in geolocation_info and
len(geolocation_info['results']) != 0 and
'locations' in geolocation_info['results'][0] and
len(geolocation_info['results'][0]['locations']) != 0
):
# By default we use the first entry unless we find one with
# geocodeQuality=city.
geolocation_result = geolocation_info['results'][0]
use_location = geolocation_result['locations'][0]['latLng']
# Loop over the locations to see if we come accross a
# geocodeQuality=city.
# If we find a city we set that to the use_location and break
for location in geolocation_result['locations']:
if(
'latLng' in location and
'lat' in location['latLng'] and
'lng' in location['latLng'] and
location['geocodeQuality'].lower() == 'city'
):
use_location = location['latLng']
break
return {
'latitude': use_location['lat'],
'longitude': use_location['lng']
}
return None
def decimal_to_dms(decimal, signed=True):
# if decimal is negative we need to make the degrees and minutes
# negative also
sign = 1
if(decimal < 0):
sign = -1
# http://anothergisblog.blogspot.com/2011/11/convert-decimal-degree-to-degrees.html # noqa
degrees = int(decimal)
subminutes = abs((decimal - int(decimal)) * 60)
minutes = int(subminutes) * sign
subseconds = abs((subminutes - int(subminutes)) * 60) * sign
subseconds_fraction = Fraction(subseconds)
if(signed is False):
degrees = abs(degrees)
minutes = abs(minutes)
subseconds_fraction = Fraction(abs(subseconds))
return (
pyexiv2.Rational(degrees, 1),
pyexiv2.Rational(minutes, 1),
pyexiv2.Rational(
subseconds_fraction.numerator,
subseconds_fraction.denominator
)
)
def dms_to_decimal(degrees, minutes, seconds, direction=' '):
sign = 1
if(direction[0] in 'WSws'):
sign = -1
return (
float(degrees) + float(minutes) / 60 + float(seconds) / 3600
) * sign
def get_key():
config_file = '%s/config.ini' % constants.application_directory
if not path.exists(config_file):
return None
config = ConfigParser()
config.read(config_file)
if('MapQuest' not in config.sections()):
return None
return config.get('MapQuest', 'key')
def place_name(lat, lon):
# Convert lat/lon to floats
if not isinstance(lat, float):
lat = float(lat)
if not isinstance(lon, float):
lon = float(lon)
# Try to get cached location first
db = Db()
# 3km distace radious for a match
cached_place_name = db.get_location_name(lat, lon, 3000)
if(cached_place_name is not None):
return cached_place_name
lookup_place_name = None
geolocation_info = reverse_lookup(lat, lon)
if(geolocation_info is not None):
if('address' in geolocation_info):
address = geolocation_info['address']
if('city' in address):
lookup_place_name = address['city']
elif('state' in address):
lookup_place_name = address['state']
elif('country' in address):
lookup_place_name = address['country']
if(lookup_place_name is not None):
db.add_location(lat, lon, lookup_place_name)
# TODO: Maybe this should only be done on exit and not for every write.
db.update_location_db()
return lookup_place_name
def reverse_lookup(lat, lon):
if(lat is None or lon is None):
return None
key = get_key()
try:
params = {'format': 'json', 'key': key, 'lat': lat, 'lon': lon}
headers = {"Accept-Language": constants.accepted_language}
r = requests.get(
'http://open.mapquestapi.com/nominatim/v1/reverse.php?%s' %
urllib.urlencode(params), headers=headers
)
return r.json()
except requests.exceptions.RequestException as e:
if(constants.debug is True):
print e
return None
except ValueError as e:
if(constants.debug is True):
print r.text
print e
return None
def lookup(name):
if(name is None or len(name) == 0):
return None
key = get_key()
try:
params = {'format': 'json', 'key': key, 'location': name}
if(constants.debug is True):
print 'http://open.mapquestapi.com/geocoding/v1/address?%s' % urllib.urlencode(params) # noqa
r = requests.get(
'http://open.mapquestapi.com/geocoding/v1/address?%s' %
urllib.urlencode(params)
)
return r.json()
except requests.exceptions.RequestException as e:
if(constants.debug is True):
print e
return None
except ValueError as e:
if(constants.debug is True):
print r.text
print e
return None