Even though most open-source software is freely distributed, your time is limited. So which software should you try first? That depends on what you want to accomplish, the kind of free software you want to deploy and the environment in which you work. The Free GIS FAQlisted below can help you identify the characteristics that are important to you. If you have more questions you want to see there, another opinion to offer, etc. let meknow.

The FAQ is followed by an annotated list of free, open-source software. Additions to the list are also most welcome. Just let meknow.

-- Sara Yurman - 20 Nov 2004

Enterprise GIS

Is there an open source, enterprise level spatial database available?

Yes.

• PostGISis an open source back-end database for spatial data, based on PostgreSQL.
• MySQLhas incorporated spatial extensions.

What if I want to keep running ArcSDE, or Oracle Spatial? Can I connect open source tools to it?

Certainly. For example, Here'sa page that describes how to connect ArcSDE to MapServer, a popular open source web map server. Here'sthe equivalent page for Oracle Spatial.

Open Source Concerns

What is free and open source software and why would I want it?

This question is not specific to GIS, and there are lots of places to explore it. Here are just a few:

• The Open Source Initiative
• The Free Software Foundation

Does this stuff actually work? How do I pick one?

In general, yes. The caveat is that your definition of "works" depends on the package and what you want to do with it. Some good rules of thumb for choosing a package are:

• Pick something widely used in organizations like yours.Look at the activity on the mailing list. If the list looks "dead", you might want to keep looking. Are the people on the list from organizations like yours? USGS uses a lot of free software. Look for them on the list. Are they doing things you want to do? You'll be in a better position to get support if there are users with similar problems.
• Pick community-based software.Some packages are projects that are completely based in a single company, others are dependent on a single person. The first can be vulnerable to budget cuts, the second could be vulnerable to the vagaries of modern life. If a package is based in a company, look for one with outside developers. If a package is the responsibility of an individual, look for a long track record and relationships with other developers and packages.
• Look for software that does what you want to do.Sounds obvious enough, but it can be easy to fall for software with an interface that looks familiar. Look through the mail list archives for people who are doing similar work.

How do I get support?

Most support for free software packages is through mailing lists. You'll find some through project web sites, or on central resources like MapTools.org. The advantage to this method is that it works well world-wide, regardless of time zones or business hours. The GIS free software community is small enough that you'll often see the software authors answering questions.

Some firms sell support for free software packages. Please let meknow if you have names of support companies for free GIS software to contribute.

What kinds of free and open source GIS software are available?

Free and open source software now encompasses the entire gamut of GIS needs. Most of these packages don't have a marketing department, so you have to find them. Software source sites are included in the list that follows this FAQ.

What arethe barriers to using free software?

If you're just starting with GIS, there aren't any.

If you have an extensive installed base consider the following:

• If you are a manageryou'll need to evaluate training needs. Remember that if you have customized packages in-house you're training anyway. Talk with someone who manages a shop based on free GIS software and see how they're fairing. And start small. Add a free web map server to your repertoire, for example, before changing any existing applications. Make sure any changes you make are simple and effective, and don't worry about going all proprietary or all open source. Purity is hardly the point.
• If you're a staff memberthink about how to make something work, or work better, with free software before approaching your manager. They have to live with the fallout from your idea. And it really shouldn't be difficult to make improvements using free and open source software.
• If you want to move your operating system to Linux, make sure you have support for it or use Knoppix. You have enough to do with GIS without adding system administration duties to your list.

Computing Environment

Can I run open source GIS software in windows?

Yes. It can be harder, depending on the software you want to run. For example, here'sthe page describing what you have to do to install PostGIS in windows. It runs through Cygwin, a Linux environment that runs within windows. That's a lot of layers to go through. Your mileage may vary.

FreeGIS.orgkeeps a good listof free GIS software that runs on windows, some of it in "native" windows and some through Cygwin.

What about my Mac?

If you're on MacOS X you shouldn't have any problem at all: it's a kind of Unix. FreeGIS.org keeps a listof free GIS software that runs on it.

What if I want to run something on Linux, but feel particularly clueless on the topic?

Never fear. Try one of the bootable CDs from the Knoppixproject. No installation required. There's even one specifically for GIS.

Java

Java is a consideration. If you need a variety of Java Virtual Machines (JVMs) on a single machine, you can start to have conflicts. Some of the open source GIS packages are built on Java. If you choose one of them, pay attention to the JVM requirements, and take note of any JVMs that are already installed on the machine. You may wish to use non-Java packages to avoid these conflicts.

What are pre-compiled binaries? Do I want them?

If you haven't compiled your own software before, yes, these are probably what you want. Most Unix systems assume you're going to want to custom compile some of your software. The tools to do it are provided with the operating system, and they're simple to use. Windows doesn't supply these tools. If you're running windows, it's easiest to get pre-compiled software that was specifically built for windows.

Free and Open Source GIS Resources

• News about free and open source GIS
  • http://www.digitalearth.org/
• Free and open source software sites specific to GIS
  • http://freegis.org/
  • http://www.maptools.org/
  • http://www.remotesensing.org/
• Free and open source software sites that include GIS
  • http://sourceforge.org/
  • http://freshmeat.org/

Bundled Software

Sometimes it's just easier to go one place. Here are some places worth going.

FWTools http://fwtools.maptools.org/

Frank Warmerdammaintains most of the open source infrastructure for handling projections and file formats. It's handy to know what and where they are, since they are often prerequisites for installing other packages: proj4and GDAL(pronounced "goodle", rhymes with noodle).

FWTools includes pre-compiled binaries for both Windows and Linux of GDAL and proj4, along with the web map server MapServer and raster-oriented desktop OpenEV. Frank contributes to or maintains all these packages.

GIS Knoppix http://www.sourcepole.com/sources/software/gis-knoppix/

GIS Knoppixis a self-booting Linux CD set up to be a sort of Linux workstation on a CD. It has office productivity tools, like OpenOffice, along with a full set of GIS tools: desktop, web map server, etc.

MapServer for Windows (MS4W) http://www.maptools.org/ms4w/index.phtml

MS4Winstalls pre-compiled windows binaries that comprise a complete development environment for making applications with the MapServerweb map server.

Enterprise GIS: Spatially Enabled Databases

PostGIS http://postgis.refractions.net/

PostGISis the most commonly used back-end database in free software. Most of the desktops listed are PostGIS clients, as well as the MapServerand GeoServerweb map servers.

MySQL http://www.mysql.com/

MySQLhas spatial extensions, and is supported in both the MapServerand GeoServerweb map servers.

Desktops

GRASS http://grass.ibiblio.org/index.html

GRASS, the Geographic Resources Analysis Support System, is a long-standing, complete GIS system. It was originally written in Unix, and runs best in Linux or Unix of some kind. Although the interfaces have recently improved it still has a learning curve. The GRASS community is enormous, and world-wide, with commensurate support resources.

JUMP http://www.jump-project.org/

JUMPsupposedly works everywhere, but is much more windows oriented. Has a nice graphical user interface (GUI), and includes conflation tools. It requires SUN's Java Virtual Machine (JVM).

OpenEV http://openev.sourceforge.net/

OpenEVis a raster-oriented viewer with some editing capability. Can display vectors, and create simple shapefiles. Most vector capabilities (snapping, etc.) are not present.

Quantum GIS (QGIS) http://qgis.org/

QGISis mostly a viewer, with some fairly new editing capabilities. It is more mature on the Linux side of the house, but does have a windows preview release. It is extremely simple to operate, and creates configuration files for the MapServer web map server.

Thuban http://thuban.intevation.org/

Thubanis a viewer, and is definitely cross-platform (Windows, Linux, etc.). It's based on Python.

UDig http://udig.refractions.net/

UDigis still in development, but may suit your needs even in its current form. It's designed to expand on JUMPfunctionality, and conform to important Open Geospatial Consortiumstandards. Refractions Researchis planning to sell support for uDig.

Web Map Servers

There are quite a variety of these. The two listed below have the most developed capabilities.

MapServer http://mapserver.gis.umn.edu/

MapServerhas a very simple set-up and is economical with system resources. It is widely supported and integrated with other packages. The MapServer community has an annual conference.

GeoServer http://geoserver.sourceforge.net/html/index.php

GeoServeris Java-based, and has a fairly complex set-up. It is widely supported, and integrated with other packages.

-- Sara Yurman - 19 Nov 2004