def geolocate(tag_sentence, username):
"""
Function to pull location information from a sentence. The location
is then passed to the `geonames_api` to obtain latitude and
longitudes for each event.
Inputs
------
tag_sentence : sentence with POS tags as generated by the NLTK
function `pos_tag()`. List of tuples.
username : username for geonames.org. String.
Returns
-------
lat : latitude coordinate
lon : longitude coordinate
"""
#TODO: What about two word cities? Baton Rouge, New Orleans, etc.
#Create bigrams
bigrams = nk.bigrams(tag_sentence)
loc = None
#Words that indicate a location
keep = ['in', 'to', 'from']
#Select words from the bigram where the first word is 'to' or 'in'
#and the second word has a proper noun tag.
for (w1, t1), (w2, t2) in bigrams:
if (w1 in keep) and (t2 == 'NNP'):
loc = w2
#If the above didn't work, try trigrams
if not loc:
trigrams = nk.trigrams(tag_sentence)
for (w1, t1), (w2, t2), (w3, t3) in trigrams:
if (t1.startswith('N') and t2 == 'IN' and t3 == 'NNP'):
loc = w3
#If it found a location
if loc:
#Create parameters to pass to the geonames_api
loc = nk.stem.PorterStemmer().stem(loc)
params = geonames_api.make_params({'q': loc})
#Try to obtain coordinates from geonames
try:
lat, lon = geonames_api.get_lat_lon(params, username)
return lat, lon
#but if something went wrong, return 'NA' for lat, lon
except IndexError:
lat, lon = 'NA', 'NA'
return lat, lon
#If a location hasn't been found, return 'NA' for lat, lon
if not loc:
lat, lon = 'NA', 'NA'
return lat, lon
def geolocate(trigrams, username):
"""
Function to pull location information from a sentence. The location
is then passed to the `geonames_api` to obtain latitude and
longitudes for each event.
Parameters
------
username: String.
Username for geonames.org.
Returns
-------
lat: String.
latitude coordinate
lon: String.
longitude coordinate
"""
#TODO: What about two word cities? Baton Rouge, New Orleans, etc.
#Create bigrams
loc = None
#Words that indicate a location
keep = ['in', 'to', 'from']
#Select words from the bigram where the first word is 'to' or 'in'
#and the second word has a proper noun tag.
for (w1, t1), (w2, t2), (w3, t3) in trigrams:
if (w1 in keep) and (t2 == 'NNP'):
loc = w2
elif (t1.startswith('N') and w2 in keep and t3 == 'NNP'):
loc = w3
#If it found a location
if loc:
#Create parameters to pass to the geonames_api
loc = nltk.stem.PorterStemmer().stem(loc)
params = geonames_api.make_params({'q': loc})
#Try to obtain coordinates from geonames
try:
lat, lon = geonames_api.get_lat_lon(params, username)
return lat, lon
#but if something went wrong, return 'NA' for lat, lon
except IndexError:
lat, lon = 'NA', 'NA'
return lat, lon
#If a location hasn't been found, return 'NA' for lat, lon
if not loc:
lat, lon = 'NA', 'NA'
return lat, lon
