Now that we have the necessary data, we're ready to start implementing our GPS Heatmap system. Create a directory named gps-heatmap to hold the suite of programs and their associated data files, and then place the two data directories you created earlier (gps-data and roads) into this directory.
We're now ready to start coding. Let's start by implementing the init_db.py program to initialize our PostGIS database.
You should already have installed Postgres when you worked through Chapter 3, Spatial Databases. We're going to use Postgres to create and initialize a database to hold all our processed road data. The first step is to create the database itself, which you can do by typing the following into a terminal window:
% createdb gps_heatmap
This should create a database named gps_heatmap. If you get an authentication error, you will need to enter a password or use the -U postgres command-line option so that the createdb command...