Get street Geojson using Openstreet's Nominaim API

README.md

Get Street Geojson using Openstreet's Nominaim API

1. Update street names in all-streets.txt.
2. Update your COUNTRY_CODE = 'sg' in geojson_generator.py.
3. Run geojson_generator.py
4. Check *.csv and geojson.json file.

Nominatim is a search engine for OpenStreetMap data. This is the debugging interface. You may search for a name or address (forward search) or look up data by its geographic coordinate (reverse search). Each result comes with a link to a details page where you can inspect what data about the object is saved in the database and investigate how the address of the object has been computed. To enhance understand of Nominatim, recommend to visit https://nominatim.openstreetmap.org/ and play for a while.

all-streets.txt

Abingdon Road
Adam Drive
Adam Park

geojson.json

geojson_generator.py

import urllib.request
import json
import csv
import os

# file path setting
OPEN_STREETS_NAMES_FILE = 'all-streets.txt'
OUTPUT_DIR = 'output'
OUTPUT_CSV_FILENAME = 'street-coordinates.csv'
OUTPUT_JSON_FILENAME = 'geojson.json'

# nominatim api address
BASE_URL = 'https://nominatim.openstreetmap.org/?format=json&polygon_geojson=1&addressdetails=1&q='

# init 
CSV_DATA = [['id', 'name', 'coordinates']]

GEOJSON = {
    "type": "FeatureCollection",
    "features": []
}

ID = 0
COUNTRY_CODE = 'sg'

def flatten(something):
    if isinstance(something, (list, tuple, set, range)):
        for sub in something:
            yield from flatten(sub)
    else:
        yield something

def split(arr, count):
     return [ arr[i:i+count] for i in range(0, len(arr), count) ]


with open(OPEN_STREETS_NAMES_FILE) as f:
    lines = f.read().splitlines()
    for street in lines:
        search_street_name = street.replace(" ", "+")
        url = f'{BASE_URL}{search_street_name}+Singapore'
        print(url)
        res_body = urllib.request.urlopen(url).read()
        content = json.loads(res_body.decode("utf-8"))
        streets = [x for x in content if x['address']['country_code'] == COUNTRY_CODE]
        streets = [d for d in streets if d.get('geojson', -1) != -1]
        coordinates = [street['geojson']['coordinates'] for street in streets if street['geojson']['type'] == 'LineString']
        
        all_coordinates = []
        row = []

        if len(streets) > 0:
            all_coordinates = split(list(flatten(coordinates)), 2)

        ID = ID + 1
        row = [ID, street, all_coordinates]

        # add to csv
        CSV_DATA.append(row)

        street_geojson = {
            "id": ID,
                "type": "Feature",
                "geometry": {
                    "type": "LineString",
                    "coordinates": all_coordinates},
                "properties": {
                    "name": street
                }
        }

        # add to geojson
        GEOJSON['features'].append(street_geojson)

if not os.path.exists(OUTPUT_DIR):
    os.makedirs(OUTPUT_DIR)

with open(f'{OUTPUT_DIR}/{OUTPUT_CSV_FILENAME}', 'w') as csvFile:
    writer = csv.writer(csvFile)
    writer.writerows(CSV_DATA)
    print("writing completed")
    csvFile.close()

with open(f'{OUTPUT_DIR}/{OUTPUT_JSON_FILENAME}', 'w') as f:
    f.write(json.dumps(GEOJSON, sort_keys=True,
                       indent=4, separators=(',', ': ')))

street-coordinates.csv

id,name,coordinates
1,Abingdon Road,"[[103.9787969, 1.3692413], [103.9787469, 1.3692966], [103.9794143, 1.3684698], [103.9794005, 1.3685049], [103.979376, 1.3685506], [103.9787969, 1.3692413]]"
2,Adam Drive,"[[103.8176052, 1.3339948], [103.8176107, 1.3340427], [103.8176123, 1.33409], [103.8176081, 1.3341221], [103.8175954, 1.3341525], [103.817576, 1.3341744], [103.8175498, 1.3341896], [103.8175177, 1.3342015], [103.8174696, 1.3342135], [103.8116705, 1.3365496], [103.8119119, 1.3365496], [103.8121614, 1.3366166], [103.8122767, 1.3367507], [103.812376, 1.3369867], [103.8125208, 1.3372978]]"
3,Adam Park,"[[103.8140937, 1.3287749], [103.8140378, 1.3288127], [103.8139981, 1.3288462], [103.8139745, 1.3288971], [103.8139726, 1.3289442], [103.8141061, 1.3291786], [103.8141291, 1.3292492], [103.8141346, 1.3293362], [103.8141172, 1.3294503], [103.8140529, 1.3296554], [103.8137841, 1.3300845], [103.8137425, 1.3302173], [103.813713, 1.3303406], [103.81374, 1.3310596], [103.81363, 1.3313742], [103.813454, 1.3315882], [103.8131354, 1.3317404], [103.8125838, 1.331864], [103.8123316, 1.331977]]"
s

Hi! Thank you for this awesome script! Just wanted to say that in addition to changing COUNTRY_CODE one need to change country on line 41: url = f'{BASE_URL}{search_street_name}+Singapore'

@dmitribogonos oops! Thanks for letting me know :)