added get_bounds function to query nominatim for admin boundaries based on lat/lon. Not used anywhere just yet

1 files changed, 38 insertions, 0 deletions

diff --git a/app/locations/models.py b/app/locations/models.py
index 5c27702..25326fc 100644
--- a/app/locations/models.py
+++ b/app/locations/models.py
@@ -1,3 +1,6 @@
+import json
+import requests
+from django.contrib.gis.geos import GEOSGeometry, fromstr, MultiPolygon
 from django.contrib.gis.db import models
 from django.contrib.sitemaps import Sitemap
 from django.utils.safestring import mark_safe
@@ -157,3 +160,38 @@ class WritingbyCountrySitemap(Sitemap):
 
     def items(self):
         return Country.objects.filter(visited=True)
+
+
+def get_bounds(lat, lon):
+    '''
+    given a set of lat,lon coords return the nearest administrative level boundary (usually turn out to be city, but sometimes it's a county, occasionally a state)
+    '''
+    r = requests.get('http://nominatim.openstreetmap.org/reverse',
+                     params={
+                         'lat': lat,
+                         'lon': lon,
+                         'accept-language': 'en',
+                         'format': 'json'
+                     })
+    r.raise_for_status()
+    data = json.loads(r.text)
+    adr = data.get('address', {})
+    city = adr.get('hamlet') or adr.get('village') or adr.get('town') or adr.get('city')
+    state = adr.get('state')
+    country = adr.get('country')
+    r = requests.get('http://nominatim.openstreetmap.org/search',
+                 params={
+                     'city': city,
+                     'state': state,
+                     'country': country,
+                     'polygon_text': 1,
+                     'format': 'json',
+                     'featuretype': 'neighborhood'
+                 })
+    r.raise_for_status()
+    data = json.loads(r.text)
+    poly = GEOSGeometry(data[0]['geotext'])
+    # Sometimes you get a multipolygon, sometimes just a polygon
+    if poly.geom_type == 'Polygon':
+        poly = MultiPolygon(fromstr(data[0]['geotext']))
+    return poly