The Cartographic Mapping Lab at cml.upenn.edu is one of the most useful tools in looking at housing and other issues. I am the only one who has authorized access, but I allow students to use the database.
The user name is charper
The password is bootbeast51
DO NOT CHANGE THE PASSWORD UNDER ANY CIRCUMSTANCES! IT REQUIRES AN OFFICIAL REQUEST AND ABOUT THREE MONTHS TO OBTAIN!
Also, make sure you log out when you are finished.
You can use any of these databases, but the most helpful for housing is Neighborhood Information System.
After you log in, you will agree to use and then see this screen:
The neighborhood base is the most useful, although you can check out the other databases.
Here is can map a specific address, an area and query specific data.
This choice provides you with the ability to search a specific address.
It is important to read how to use this database. It is not incredibly difficult, but you really need to know how to query, save data and use the material to your best advantage.