polymaps.appspot.com

app.yaml

application: polymaps
version: 1
runtime: python
api_version: 1

handlers:
- url: /state/.*
  script: main.py

- url: /county/.*
  script: main.py

- url: /
  script: main.py

main.py

#!/usr/bin/env python
#
# Copyright 2007 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

import wsgiref.handlers
import os
from google.appengine.ext import webapp
from google.appengine.ext.webapp import util

class MainHandler(webapp.RequestHandler):
  def get(self):
    self.response.out.write('Hello world!')

class JsonHandler(webapp.RequestHandler):
  def get(self):
    path = os.path.join(os.path.dirname(__file__), self.request.path[1:])
    self.response.headers.add_header("Access-Control-Allow-Origin", "*")
    if os.path.exists(path):
      self.response.out.write(open(path, 'r').read())
    else:
      self.response.out.write('{"type":"FeatureCollection","features":[]}')

def main():
  application = webapp.WSGIApplication([
      ('/', MainHandler),
      ('/state/.*', JsonHandler),
      ('/county/.*', JsonHandler),
      ], debug=False)
  wsgiref.handlers.CGIHandler().run(application)

if __name__ == '__main__':
  main()

scraper.py

import os
import errno
import re
from urllib import urlopen
from json import JSONEncoder

import ModestMaps
import geojson
import simplejson
from shapely.geometry import asShape
from shapely.geometry import asPolygon

if __name__ == '__main__':

    provider = ModestMaps.builtinProviders['OPENSTREETMAP']()
    float_pat = re.compile(r'^-?\d+\.\d+$')

    def mkdir_p(path):
        try:
            os.makedirs(path)
        except OSError as exc: # Python >2.5
            if exc.errno == errno.EEXIST:
                pass
            else: raise

    def scrape(row, col, zoom):
        nw = provider.coordinateLocation(ModestMaps.Core.Coordinate(row, col, zoom))
        se = provider.coordinateLocation(ModestMaps.Core.Coordinate(row + 1, col + 1, zoom))
        url = 'http://localhost/pushpin?area=county&where=bbox:{nw.lat:f},{se.lon:f},{se.lat:f},{nw.lon:f}&zoom={Z}'.format(nw=nw, se=se, Z=zoom)
        print url
        fcb = geojson.loads(urlopen(url).read())

        if not len(fcb['features']):
            return

        nwc = provider.coordinateLocation(ModestMaps.Core.Coordinate(row - .01, col - .01, zoom))
        sec = provider.coordinateLocation(ModestMaps.Core.Coordinate(row + 1.01, col + 1.01, zoom))
        clip = asPolygon([[nwc.lon, nwc.lat], [sec.lon, nwc.lat],  [sec.lon, sec.lat], [nwc.lon, sec.lat]])
        match = 0

        for f in fcb['features']:
            g = f['geometry']
            shape = asShape(f['geometry'])
            if shape.intersects(clip):
                match = 1
                f['geometry'] = geojson.loads(geojson.dumps(shape.intersection(clip)))
            else:
                f['geometry'] = geojson.loads('{}')

        if not match:
            return

        dir = 'scrape/{Z}/{X}'.format(X=col, Y=row, Z=zoom)
        mkdir_p(dir)
        file = 'scrape/{Z}/{X}/{Y}.json'.format(X=col, Y=row, Z=zoom)
        print file
        open(file, 'w').write(''.join([(float_pat.match(x) and ('%.6f' % float(x)) or x) for x in JSONEncoder(separators=(',', ':')).iterencode(fcb)]))

        if zoom < maxZoom:
            zoom += 1
            row <<= 1
            col <<= 1
            scrape(row, col, zoom)
            scrape(row, col + 1, zoom)
            scrape(row + 1, col, zoom)
            scrape(row + 1, col + 1, zoom)

    minZoom = 3
    maxZoom = 7
    for row in range(0, 1 << minZoom):
        for col in range(0, 1 << minZoom):
            scrape(row, col, minZoom)

How can it work in http://bl.ocks.org/mbostock?