A simple example of visualizing geoson data in python using Folium. We obtain Philly Indego bike data from opendataphilly website. We download the data using the website’s free public api.

import json,urllib2
import pandas as pd

# add a header so that the website doesnt give 403 error
opener = urllib2.build_opener()
opener.addheaders = [('User-agent', 'Mozilla/5.0')]
response = opener.open('https://api.phila.gov/bike-share-stations/v1')

# parse json using pandas
df = pd.read_json(response)
df.head()
features type
0 {u'geometry': {u'type': u'Point', u'coordinate... FeatureCollection
1 {u'geometry': {u'type': u'Point', u'coordinate... FeatureCollection
2 {u'geometry': {u'type': u'Point', u'coordinate... FeatureCollection
3 {u'geometry': {u'type': u'Point', u'coordinate... FeatureCollection
4 {u'geometry': {u'type': u'Point', u'coordinate... FeatureCollection


Now, df is a dictionary of dictionaries. We are interested in the features column. Each entry looks like this.

df['features'][0]

{u'geometry': {u'coordinates': [-75.16374, 39.95378], u'type': u'Point'},
 u'properties': {u'addressCity': u'Philadelphia',
  u'addressState': u'PA',
  u'addressStreet': u'1401 John F. Kennedy Blvd.',
  u'addressZipCode': u'19102',
  u'bikesAvailable': 6,
  u'closeTime': u'23:58:00',
  u'docksAvailable': 19,
  u'eventEnd': None,
  u'eventStart': None,
  u'isEventBased': False,
  u'isVirtual': False,
  u'kioskId': 3004,
  u'kioskPublicStatus': u'Active',
  u'name': u'Municipal Services Building Plaza',
  u'openTime': u'00:02:00',
  u'publicText': u'',
  u'timeZone': u'Eastern Standard Time',
  u'totalDocks': 25,
  u'trikesAvailable': 0},
 u'type': u'Feature'}

# number of rows (bike stations)
len(df["features"])

73

We organize data first before plotting to follow a Folium example. Basically we need to create a list of tuples with latitude and longtitude. We called it coordinates.

# Organize data
coordinates = []

for i in range(0,len(df['features'])):
    coordinates.append(((df["features"][i]["geometry"]['coordinates'])))

# convert list of lists to list of tuples      
coordinates = [tuple([i[1],i[0]]) for i in coordinates] 
print(coordinates[0:10])

[(39.95378, -75.16374), (39.94733, -75.14403), (39.9522, -75.20311), (39.94517, -75.15993), (39.98082, -75.14973), (39.95576, -75.18982), (39.94711, -75.16618), (39.96046, -75.19701), (39.94217, -75.1775), (39.96317, -75.14792)]

Let’s visualize the coordinates geoson data using Folium.

import folium
import numpy as np

#print(folium.__file__)
#print(folium.__version__)

# get center of map
meanlat = np.mean([i[0] for i in coordinates])
meanlon = np.mean([i[1] for i in coordinates])

# initialize map
mapa = folium.Map(location=[meanlat, meanlon],
                  tiles='OpenStreetMap', zoom_start=13)
# add markers
for i in range(0,len(coordinates)):
    
    # create popup on click
    html="""
    Address: {}<br>
    Bikes available: {}<br>
    Docks: {}<br>
    """
    html = html.format(df['features'][i]['properties']['addressStreet'],\
               df['features'][i]['properties']['bikesAvailable'],\
               df['features'][i]['properties']['docksAvailable'])
    iframe = folium.element.IFrame(html=html, width=150, height=150)
    popup = folium.Popup(iframe, max_width=2650)
    
    #  add marker to map
    folium.Marker(coordinates[i],
                  popup=popup,
                 ).add_to(mapa)

mapa # show map


We can cluster nearby points. Also, let’s look at a different background by changing the tiles argument. List of available tiles can be found in Folium github repo.

from folium.plugins import MarkerCluster # for marker clusters

# initialize map
mapa = folium.Map(location=[meanlat, meanlon],
                  tiles='Cartodb Positron', zoom_start=13)

# add marker clusters
mapa.add_children(MarkerCluster(locations=coordinates, popups=coordinates))
mapa


We can utilize Folium plugins to view the geoson data in different ways. For example, let’s generate a heat map of the bike stations in Philly. We can see that there are dense areas in center city and Chinatown mostly.

from folium.plugins import HeatMap

# initialize map
mapa = folium.Map(location=[meanlat, meanlon],
                  tiles='Cartodb Positron', zoom_start=13)

# add heat
mapa.add_children(HeatMap(coordinates))
mapa


For more examples go to the Folium’s examples page.

Resources used