This post is a quick instruction for installing Postgres 9.2, PostGIS 2.0 and pgRouting 2.0.

1. For Postgres, download the installer from enterprisedb.com.
2. Run the installer. You’ll have to pick a superuser password – remember it, you’ll need it again soon.
3. At the end of the installation process, allow the installer to start Stack Builder.
4. In Stack Builder, select the Postgres 9.2 installation and install PostGIS from the list of available extensions.
5. The PostGIS installation procedure will prompt you for the superuser password you picked before.
6. I suggest letting the installer create a sample database We’ll need it later anyway.

Now for the pgRouting part:

1. Download the pgRouting zip file for your system (32 or 64 bit) from Winnie.
2. Unzip the file. It contains bin, lib and share folders as well as two text files.
3. Copy these folders and files over to your Postgres installation. In my case C:\Program Files\PostgreSQL\9.2

Installation – done.

Next, fire up pgAdmin. If you allowed the PostGIS installer to create a sample database, you will find it named postgis20 or similar. Otherwise just create a new database using the PostGIS template database. You can enable pgRouting in a database using the following steps:

1. In postgis20, execute the following query to create the pgrouting extension. This will add the pgRouting-specific functions:

   CREATE EXTENSION pgrouting;

2. Test if everything worked fine:

   SELECT pgr_version();

   It should return "(2.0.0-dev,v2.0.0-beta,18,a3be38b,develop,1.46.1)" or similar – depending on the version you downloaded.

How about some test data? I’ll be using the public transport network of the city of Vienna provided in GeoJSON format from http://data.wien.gv.at/daten/geo?service=WFS&request=GetFeature&version=1.1.0&typeName=ogdwien:OEFFLINIENOGD&srsName=EPSG:4326&outputFormat=json:

1. Just copy paste the url in Add Vector Layer | Protocol to load the dataset.
2. Use DB Manager to load the layer into your database. (As you can see in the screenshot, I created a schema called network but that’s optional.)

1. To make the line vector table routable, we use pgr_createTopology. This function assumes the columsn called “source” and “target” exist so we have to create those as well:

   alter table network.publictransport add column source integer;
   alter table network.publictransport add column target integer;
   select pgr_createTopology('network.publictransport', 0.0001, 'geom', 'id');
   

   I’m quite generously using a tolerance of 0.0001 degrees to build the topology. Depending on your dataset, you might want to be more strict here.

2. Let’s test it! Route from source #1 to target #3000 using pgr_dijkstra:

   SELECT seq, id1 AS node, id2 AS edge, cost, geom
     FROM pgr_dijkstra(
       'SELECT id, source, target, st_length(geom) as cost FROM network.publictransport',
       1, 3000, false, false
     ) as di
     JOIN network.publictransport pt
     ON di.id2 = pt.id ;

   Note how the query joins the routing results and the network table together. (I’m aware that using the link length as a cost attribute will not lead to realistic results in a public transport network but bear with me for this example.)

3. We can immediately see the routing results using the Load as new layer option:

Nice work! pgRouting 2.0 has come a long way. In a post from April this year, Boston GIS even announced to add pgRouting into the Stack Builder. That’s going to make the installation even more smooth.