Introduction

In order to build postGIS you need some artifacts from the postgresQL development package. This is not as straight forward as it should be.  I encourage you to take a few minutes to read this through. First, your "disto repository" is not likely to be up to date with respect to postgresql packages. In other words, if you blindly type "yum install postgresql-devel", you may have trouble getting everything installed properly. I've seen errors regarding missing libraries and the like. To avoid the fuss, when you are installing postgresql packages, use the postgresql repositories instead of your ditsro repsository.

Here is how you do that. You should read this from top to bottom.
    http://yum.pgsqlrpms.org/howtoyum.php
Also read this; you can safley skip sections on this page.
    http://www.postgresonline.com/journal/index.php?/archives/45-An-Almost-Idiots-Guide-to-PostgreSQL-YUM.html

And this is good too:
    http://postgis.refractions.net/docs/ch02.html

Did you do your reading?

Main

We assume you have already installed postgresql.

First install these packages:
proj4 installgeos install

OK, now we build postGIS.

$ yum install postgresql-devel
$ tar xvfz postgis-1.3.1.tar.gz
$ cd postgis-1.3.1
$ ./configure \--with-pgsql=/usr/bin/pg_config \--with-geos=/usr/local/bin/geos-config \--with-proj=/usr/local
$ make
$ su
$ make install
$ exit

Errors I've seen:

error

configure: error: Can't find 'flex'

solution

yum install flex

make a postgis_template

This is optional.
This page shows how to create and use a db template:
http://geospatial.nomad-labs.com/2006/12/24/postgis-template-database/

make a database

You can make a postgis db "by hand" (see below)<br>
Or you can make a postgis db by using the template (see previous)<br>

$ su postgres
$ cd
$ createdb sfmaps
$ createlang plpgsql sfmaps
$ psql \-f /usr/share/lwpostgis.sql \-d sfmaps (error: could not load library)
$ psql \-f /usr/share/spatial_ref_sys.sql \-d sfmaps
$ psql sfmaps

if you encounter this error:

libgeos_c.so.1: cannot open shared object file: No such file or directory<br>

do this<br>
Add /usr/local/lib to the dynamic linker run-time bindings

echo '/usr/local/lib' >> /etc/ld.so.conf.d/local-lib.conf
ldconfig

test

How do we know if everything is working properly?

First, follow the install instructions (which I may not have included herein - sorry!)

    http://postgis.refractions.net/docs/ch02.html#id2630100

Have the developers run the automated unit tests. But if your impatient I think the following should work...

...test proj4 by running this SQL

    select asewkt(transform(GeomFromText('POINT(-122.4195 37.77767)', 4326), 900913))

If proj4 is installed and running properly you should see a couple of numbers reasonably close to these:

6007068, 2111312

If not, you’ll get a SQL error.

To test geos run this sql (needs eas database to be restored):
todo: need some sql here that does not require a database

    select *
    from
        address_base ab,
        addresses a
    where contains(
        st_transform(
            st_envelope(ST_GeomFromEWKT('SRID=4326;POLYGON((-122.42134 37.77179 0,-122.42134 37.77780 0,-122.41537 37.77780 0,-122.41537 37.77179 0,-122.42134 37.77179 0))')),
            2227
        ),
        ab.geometry
    )
    and ab.address_base_id = a.address_base_id
    limit 100;