PPA (Philadelphia Parking Authority)

This repo is a set of scripts for scraping parking ticket data from the Philadelphia Parking Authority website. I have yet to find a good use for it.

Setup

The following Python modules are required:

$ easy_install pymongo
$ easy_install requests
$ easy_install bottle
$ easy_install beautifulsoup4

Importing the database

From the same directory as this README:

$ mongorestore

This creates one database, ppa, with two collections:

ticket

Example of an unresolved ticket:

{
    "_id" : 58536252,
    "magic-num" : 8,
    "issueDate" : "01/18/2013",
    "time" : "11:37PM",
    "issueTime" : ISODate("2013-01-18T23:37:00Z"),
    "location" : "400 BLK N 7TH ST ES",
    "meterNumber" : "7828215",
    "plate" : "PAGNF5261",
    "resolved" : false,
    "valid" : true,
    "violation" : "METER EXPIRED CC",
    "violationCode" : "1210051  C"
}

Example of a resolved ticket:

{
    "_id" : 58536710,
    "magic-num" : "5"
    "resolved" : true,
}

The actual PPA ticket number consists of a consecutive 8-digit number, followed by a "magic" digit, for which there is a semi-predictable pattern.

location

Locations are geocoded using the Google Geocoding API.

Example of a location:

{
    "_id" : ObjectId("510afb526f9bdd39b0bc3567"),
    "checked" : true,
    "distance" : 2.9851718406691896,
    "location" : {
        "lat" : 39.9601501,
        "lng" : -75.1971039
    },
    "text" : "3800 LANCASTER AV PHILADELPHIA PA"
}

Here, distance is the distance from this point to City Hall, and is used to filter out bad geolocations.

Collecting more data

The system is set up so that the "master" interacts with the DB and receives RESTful calls from any number of "slaves", which can operate on different machines. This was done to pre-empt any IP blocking, which did not occur.

$ ./master.py
$ ./slave.py

The PPA website is frail, however, and currently cannot handle more than one or two slaves simultaneously before it goes down. The slaves are rate-limited to give the site enough breathing room to handle one or two of them. It is not recommended to run more than two slaves.

You can request the data for a specific 8-digit ticket ID using the single_slave command-line utility:

$ ./single_slave 58536710

Geocoding

The "master" does not geocode automatically. This is because the Google Geocoding API rate-limits geocoding requests, as well as having a daily limit on the number of requests (2500). In order to play nice, geocoding is done as a separate function. Simply:

$ ./geocode.py

Note

If you fork this repo and produce additional ticket data, please submit a patch to push a new dump back.