PostGIS install on Ubuntu 12.04

11 years, 6 months ago

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This post shows you (and me when I forget in a couple of months!) how to set up a basic toolchain for spatial queries on Ubuntu 12.04. After installing PostgreSQL and PostGIS, we'll load data from a shapefile, try some queries, and display the spatial database layer in QGIS

Step 1: Install PostGIS

Install the packages you’ll need

sudo apt-get install postgresql-9.1-postgis postgresql-contrib-9.1 pgadmin3

Become postgres user

sudo -u postgres

Create a separate database user for your spatial databases

createuser -SdR gisuser

Create your database

createdb -E UTF8 -O gisuser dbname

Load the pl/pg procedural language (the postgis functions are written using this)

createlang plpgsql dbname

Load the postgis spatial functions

psql -d dbname -f /usr/share/postgresql/9.1/contrib/postgis-1.5/postgis.sql

Load the spatial reference systems table

psql -d dbname -f /usr/share/postgresql/9.1/contrib/postgis-1.5/spatial_ref_sys.sql

Change table ownership

psql dbname -c "ALTER TABLE geometry_columns OWNER TO gisuser"

psql dbname -c "ALTER TABLE spatial_ref_sys OWNER TO gisuser"

Change the postgres user’s database password so you can use it to log in with pgadmin3, and the gisuser’s password so you know what it is

psql dbname

ALTER USER postgres WITH PASSWORD 'newpassword';

ALTER USER gisuser WITH PASSWORD 'gispassword';/q

Log out of postgres user session

exit

Step 2: Look at your new database in pgadmin3

Load up pgadmin3. click the plug icon to create a new connection.

• name: localhost
• server: localhost
• user: postgres
• password: the database password you set for the postgres user

If it connects successfully, expand server groups > servers > localhost > databases, and click the name of your database (if you can’t expand something, click once to connect, then try again). you’ll see the objects that make up your database. to see tables, expand schemas > public > tables. if you click on a table, you’ll see the SQL create statement that made it in the pane in the lower right corner of the window.

You should see two tables: spatial_ref_sys and geometry_columns

Step 3: Try a query in pqadmin3

Click the SQL magnifying glass icon in the pgadmin3 toolbar

Try the following:

SELECT srtext FROM spatial_ref_sys WHERE srid = 4269;

Run the query using the green pay button in this window’s toolbar. you should see information about this projection.

Step 4: Load the zipcodes shapefile into the database

Download a file of california zipcodes from http://www.census.gov/geo/cob/bdy/zt/z500shp/zt06_d00_shp.zip

sudo cp Downloads/zt06_d00_shp.zip /var/lib/postgresql/

sudo chmod 777 /var/lib/postgresql/zt06_d00_shp.zip

sudo su - postgresunzip zt06_d00_shp.zip

shp2pgsql -c -D -s 4269 -I zt06_d00.shp public.zipcodes > zips.sql

psql -d dbname -f zips.sql

psql dbname -c "ALTER TABLE zipcodes OWNER TO gisuser"

exit

Step 5: Look at the zipcodes spatial table in QGIS

sudo apt-add-repository ppa:ubuntugis/ubuntugis-unstable

sudo apt-get update

sudo apt-get install qgis

Start qgis from terminal or gui menu

In top menu, click layer > add postgis layer

• name: dbname
• service:
• host: localhost
• database: dbname
• user: gisuser
• password: gispassword

Click test connection - if it works, check the boxes to save username and password then click ok.

Click connect to connect to the connection you just set up. select the zipcodes table and click add.

Zipcode polygons appear!

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