server0.py

from __future__ import division

from flask import Flask, send_from_directory, jsonify
from random import randint
import math
import pandas as pd

app = Flask(__name__, static_url_path='/')

# http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
def num2deg(xtile, ytile, zoom):
    n = 2.0 ** zoom
    lon_deg = xtile / n * 360.0 - 180.0
    lat_rad = math.atan(math.sinh(math.pi * (1 - 2 * ytile / n)))
    lat_deg = math.degrees(lat_rad)

    lat_deg += 0.001 if lat_deg==0.0 else 0.0
    lon_deg += 0.001 if lon_deg==0.0 else 0.0
    return (lat_deg, lon_deg)

@app.route('/jsonData/<x>/<y>/<z>')
def buildData(x,y,z):
    x = int(x)
    y = int(y)
    z = int(z)
    lat,lon = num2deg(x, y, z)

    #  latitudes 50 and 54 N, and longitudes 3 and 8 E.
    if 48 <= lat <= 56 and 3 <= lon <= 8:
        data = dutchData(lat,lon,z)
    elif 38 <= lat <= 48 and 3 <= lon <= 8:
        data = queryData(x, y, z)
    else:
        # data = randomData(lat,lon)
        data = []
    return jsonify(data)

def randomData(lat,lon):
    bluePart = randint(10,90)
    return [{
        "location": [ lon, lat ],
        "A": bluePart,
        "B": 100 - bluePart,
    }]

def dutchData(lat,lon,z):
    if z < 8:
        # Return aggregated data
        return [{
            "location": [ 5.0, 52.0 ],
            "A": 25,
            "B": 75,
        }]
    else:
        # Return expanded data
        return [{
            "location": [ 4.8, 52.3 ],
            "A": 90,
            "B": 10,
        }, {
            "location": [ 5.8, 51.8 ],
            "A": 10,
            "B": 90,
        }]

def buildPieData(latlon, group):
    d = group.groupby('cat').size().to_dict()
    nItems = sum(d.values())
    data = { k:100 * v/nItems for k,v in d.iteritems() }
    data["location"] = [ latlon[1], latlon[0] ]
    return data

def queryData(x,y,z):
    lat0,lon0 = num2deg(x, y, z)
    lat1,lon1 = num2deg(x + 1, y + 1, z)
    # Here instead of loading data from file, we will load data clustered
    # for the lat/lon we are intereste on
    data = pd.read_csv('data.csv', sep=' ', names=['lat', 'lon', 'w', 'cat'])
    byLL = data.groupby(['lat', 'lon'])
    return [ buildPieData(latlon,g) for latlon,g in byLL ]

@app.route('/<path:path>')
def send_files(path):
    return send_from_directory('', path)

app.run(host='0.0.0.0', port=8000, debug=True)