Query database instead of overpass

geocode/model.py

@@ -2,6 +2,10 @@ from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.schema import Column
 from sqlalchemy.types import Integer, Float, Numeric, String
 from sqlalchemy.dialects import postgresql
+from sqlalchemy.orm import column_property
+from sqlalchemy.ext.hybrid import hybrid_property
+from sqlalchemy import func
+
 from geoalchemy2 import Geometry
 from .database import session
 
@@ -12,10 +16,22 @@ class Polygon(Base):
     __tablename__ = "planet_osm_polygon"
 
     osm_id = Column(Integer, primary_key=True, autoincrement=False)
+    admin_level = Column(String)
 
     way_area = Column(Float)
     tags = Column(postgresql.HSTORE)
     way = Column(Geometry("GEOMETRY", srid=4326, spatial_index=True), nullable=False)
+    area = column_property(func.ST_Area(way))
+
+    @hybrid_property
+    def area_in_sq_km(self):
+        return self.area / (1000 * 1000)
+
+    @classmethod
+    def coords_within(cls, lat, lon):
+        point = func.ST_SetSRID(func.ST_MakePoint(lon, lat), 4326)
+        return cls.query.filter(cls.admin_level.isnot(None),
+                                func.ST_Within(point, cls.way))
 
 class Scotland(Base):
     __tablename__ = "scotland"

geocode/overpass.py

@@ -1,36 +0,0 @@
-from flask import current_app
-from . import headers
-import os
-import json
-import requests
-
-OVERPASS_URL = "https://lz4.overpass-api.de"
-
-
-def run_query(oql):
-    return requests.post(
-        OVERPASS_URL + "/api/interpreter", data=oql.encode("utf-8"), headers=headers
-    )
-
-
-def is_in_lat_lon(lat, lon):
-    oql = f"""
-[out:json][timeout:25];
-is_in({lat},{lon})->.a;
-(way(pivot.a); rel(pivot.a););
-out bb tags qt;"""
-
-    return run_query(oql)
-
-
-def get_osm_elements(lat, lon):
-    filename = f"cache/{lat}_{lon}.json"
-    use_cache = current_app.config["USE_CACHE"]
-
-    if use_cache and os.path.exists(filename):
-        return json.load(open(filename))["elements"]
-
-    r = is_in_lat_lon(lat, lon)
-    if use_cache:
-        open(filename, "wb").write(r.content)
-    return r.json()["elements"]

lookup.py

@@ -2,10 +2,9 @@
 
 from flask import Flask, render_template, request, jsonify, redirect, url_for
 import geocode
-from geocode import wikidata, overpass, scotland, database, model
+from geocode import wikidata, scotland, database, model
 import urllib.parse
 import random
-from geopy.distance import distance
 
 # select gid, code, name from scotland where st_contains(geom, ST_Transform(ST_SetSRID(ST_MakePoint(-4.177, 55.7644), 4326), 27700));
 
@@ -32,15 +31,6 @@ def get_random_lat_lon():
     return lat, lon
 
 
-def bounding_box_area(element):
-    bbox = element["bounds"]
-
-    x = distance((bbox["maxlat"], bbox["minlon"]), (bbox["maxlat"], bbox["maxlon"]))
-    y = distance((bbox["minlat"], bbox["maxlon"]), (bbox["maxlat"], bbox["minlon"]))
-
-    return x.km * y.km
-
-
 def wd_to_qid(wd):
     # expecting {"type": "url", "value": "https://www.wikidata.org/wiki/Q30"}
     if wd["type"] == "uri":
@@ -131,7 +121,7 @@ def lat_lon_to_wikidata(lat, lon):
 
         return {"elements": elements, "result": result}
 
-    elements = overpass.get_osm_elements(lat, lon)
+    elements = model.Polygon.coords_within(lat, lon)
     result = do_lookup(elements, lat, lon)
 
     # special case because the City of London is admin_level=6 in OSM
@@ -190,12 +180,10 @@ def get_commons_cat_from_gss(gss):
 
 
 def osm_lookup(elements, lat, lon):
-    elements.sort(key=lambda e: bounding_box_area(e))
+    elements = sorted(elements, key=lambda e: e.area)
 
     for e in elements:
-        if "tags" not in e:
-            continue
-        tags = e["tags"]
+        tags = e.tags
         admin_level_tag = tags.get("admin_level")
         admin_level = (
             int(admin_level_tag)
@@ -265,7 +253,7 @@ def index():
 def random_location():
     lat, lon = get_random_lat_lon()
 
-    elements = overpass.get_osm_elements(lat, lon)
+    elements = model.Polygon.coords_within(lat, lon)
     result = do_lookup(elements, lat, lon)
 
     return render_template(
@@ -286,7 +274,7 @@ def wikidata_tag():
         elements = []
         result = build_dict(hit, lat, lon)
     else:
-        elements = overpass.get_osm_elements(lat, lon)
+        elements = model.Polygon.coords_within(lat, lon)
         result = do_lookup(elements, lat, lon)
 
     return render_template(

templates/detail.html

@@ -32,7 +32,7 @@
 
 {% for element in elements %}
 {% set tags = element.tags %}
-  <pre>{{ element | pprint }}</pre>
+  <pre>{{ element.tags | pprint }}</pre>
 {% endfor %}