Query database instead of overpass

This commit is contained in:
Edward Betts 2021-04-17 18:31:58 +02:00
parent 54b280655f
commit 44241751b2
4 changed files with 23 additions and 55 deletions

View file

@ -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"

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@ -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"]

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@ -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(

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