Jeremy Tunnell

Announcements

Thumbtack just rolled out new landing pages! Read More »

Favorite Sites

• Thumbtack - Your marketplace for local services
• Rostr - My personal project.
• Neighborhood Bands - My other personal project.
• Ars Technica
• Daily Worse Than Failure
• Joel on Software
• Coding Horror
• A List Apart
• Evhead
• High Scalability

PostGIS Basics - Part 1 - Installation

Why PostGIS?

PostGIS (good writeup) is actually the main reason I chose to go with PostgreSQL over MySQL for this new project I'm working on (there are many other benefits, though, and I really can't see myself ever going back). I'll leave the discussion of capabilities for another post, but for now I thought I'd share my experience installing and configuring this (very) squirrely extension to PostgreSQL.

Installation

Using the official documentation (which, unfortunately and like every other linux application, assumes that you are compiling from source) and a very helpful PostGIS basics guide I was able to get 90% there.

My OS is CentOS, so I used yum to handle installs from the rpm database. The thing with CentOS is that it is purposefully one step behind the cutting edge, so the most recent version of certain applications are not available (PHP, Postgres, etc). To get around this limitation, you have to instruct CentOS to look elsewhere for updated RPMs.

One location is the Postgresql repository: http://www.postgresql.org/download/linux

Another location for these is DAG. To set this as an additional rpm source, run this command as root (this works for RHEL 5 and CentOS):

rpm -Uhv http://apt.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0.3.6-1.el5.rf.i386.rpm

Now we have the ability to get more up-to-date rpms.

Next, we must work on getting all of the dependencies for PostGIS installed, which amount to:

• ProJ4
• GEOS 3
• The PL/pgSQL procedural language

Proj4

Unfortunately, rpms for the proj-4 application still weren't available from the repository, so I found an rpm here: Proj-4 rpms. This installed with a quick rpm -U software-2.3.4.rpm

GEOS

Geos is thankfully available from Dag, so yum should find it and install it. There may be some weird dependencies you will have to work through. The below packages should help, but they'll all have to be installed eventually, so you may as well go ahead and do it.

• php-pear
• php-devel

* At this point, if you are using PDO and haven't installed the pgsql PDO drivers, you can do it now: "pecl install pdo_pgsql"

PL/pgSQL

You'll need to run the following commands from a command line (either as root or the postgres user, I can't recall which one is needed by which). Please note all of these paths seem to be unique to each installation, so yours might be different.

/usr/bin/initdb -D /var/lib/pgsql/data_dir    //Create the database

psql create language plpgsql  

psql -d database_name -f /usr/share/pgsql/contrib/lwpostgis.sql
psql -d database_name -f /usr/share/pgsql/contrib/spatial_ref_sys.sql

The last two lines load the spacial functions into the database for use.

Comments