Purchased programs require an up-front cost, but generally offer greater support, better user interfaces, and more analytical tools.  Many free GIS programs offer limited functionality and little to no support other than user forums.  However, free tools may contain specific tools or interoperability with statistical programs necessary for your work. Many paid programs also offer a free viewer with limited functionality.

Two notes on this document.  First, this is in no way comprehensive.  There are dozens of GIS programs available on the market (and often small but significant differences between programs).  If you need a specific tool or function for your work, it is worth doing the leg work before diving in.

Second, many governments and corporations use custom GIS programs (such as IRIS by the Mexican Government or PX-Map by the Norwegian and Swedish governments).  These often include country- or industry-specific data, but often at the cost of not being able to export to another program.

ESRI (ArcGIS)

ESRI is the industry standard, and the shapefile (.shp) file serves as the most interoperable file in the GIS community.  However, as market leader, ESRI has emphasized the development of certain functions, while neglecting others.  For example, ArcGIS does not work on Apple computers, and ArcGIS does not have native tools for some GIS functions like precincting/redistricting, and many scholars have criticized its statistical computing tools as being too limited and inflexible. Starting with Arc10, ArcGIS incorporates the ability to use the Python scripting language to edit the statistical tools.

Availability: Students at UCSD can obtain a free copy of ArcMap from the GIS Coordinator at Geisel Library, Mike Smith.

Other Paid Programs

Maptitude (Caliper)

Maptitude offers a much simpler GIS framework than ArcGIS, and simplifies many tasks sucks as editing tables and geocoding.  However, it lacks the scope of the analytical tools that ArcGIS offers. It is the industry leader program in redistricting and commonly used for precincting and electoral work.  Its sister product TransCAD is also heavily used in the transportation industry for modeling and working with transportation data.  Maptitude requires Windows or a Windows partition on Apple.

MapInfo (Pitney Bowes)

Once ArcGIS’ leading competitor, MapInfo continues to be a common alternative in business environments.  Its close integration with the Microsoft suite of products, including Bing and Silverlight, is one of its key strengths.  However, like Maptitude, the scope of editing tools is limited.  MapInfo requires Windows.

Free Stand-Alone Programs

Free programs may be open source (OpenGeo), in which the program’s code is available for viewing and modifying, or closed source, where the program is free, but the code is secret and may not be modified.  Most free government programs like GRASS are closed source but free.  Free stand-alone programs generally offer similar mapping functionality as the paid programs, but often have limited analytical capabilities—though they can be paired with the extensions for R or Stata.  Here is a selection of free programs that launch a stand-alone program when installed:

GRASS (http://grass.osgeo.org/) is probably the best of the open-source GIS options.  Sponsored by the US Corps of Engineers as well as numerous universities and government agencies across the world, GRASS allows users to create C/C++ or Python modules which can be added to the basic GIS editor, much in the same way as the R package works.  GRASS is a particularly good option for Mac or Unix-based users.  Support is entirely community-based.

GeoDA (http://geodacenter.asu.edu/) is a good program for spatial statistics, offering a wider array of tools than the ArcGIS Spatial Statistics toolbox.  The main drawbacks of GeoDA are the lack of support and the infrequent updates, but it offers a visual user-interface alternative for spatial statistics to the R or Stata packages below.

OpenGeo (http://opengeo.org/) and Quantum GIS (http://qgis.org/) are both free, open source, stand-alone GIS programs that use the shapefile file format. Both programs allow users to create and modify maps, though both have limited statistical/analytical capabilities.  Support is community-based through forums and wikis, though OpenGeo has a paid option (Enterprise Edition) which includes tech support.

Google Earth (http://www.google.com/earth/index.html) is more focused on visualization than analysis, but its widespread use demands consideration.  Google Earth offers quick map creation and data display of custom data in coordinate or address form.  Its analytical tools are limited, and most are found at the for-pay, “Google Earth Enterprise” levels only. 

DIVA-GIS (http://diva-gis.org) is a free computer program for mapping and geographic data analysis. With DIVA-GIS you can make maps of the world, or of a very small area, using, for example, state boundaries, rivers, a satellite image, and the locations of sites where an animal species was observed. They also provide free spatial data for the whole world that you can use in DIVA-GIS or other programs.  DIVA-GIS is particularly useful for mapping and analyzing biodiversity data, such as the distribution of species, or other 'point-distributions'. It reads and write standard data formats such as ESRI shapefiles, so interoperability is not a problem. DIVA-GIS runs on Windows and (with minor effort) on Mac OSX (see instructions).

Extensions for other programs

These tools do not have their own programs, but rather work in the context of another program (like R) to allow a user to do spatial analysis without needing to install a program with a mapping interface.  These extensions often contain the greatest analytical power (and are the easiest to work with in developing new tools for the computer programmers), but this generally comes at the cost of limited control over the final map produced—or the geographic files must be exported to another program like ArcGIS to make a report-quality map.

Free Tools for R (http://cran.r-project.org/web/views/Spatial.html)

The website above provides a good overview of the many packages for R that can be used to perform spatial analysis. sp is the core library for handling spatial data in R.  Other packages like Spatstat (basic spatial statistics), and spdep (geospatial regression) are purely analytical tools, while others like maps (map creation), maptools (tools for improving map look), and RArcInfo (converting ArcGIS files) deal with map creation.

Free Tools for Stata [version 9 or newer] (http://www.stata.com/support/faqs/graphics/spmap.html)

As with R, Stata has several extensions for dealing with spatial data.  Unlike R, however, Stata can only work with data in the shapefile or MapInfo formats, so you will need to convert your data to one of these two formats before uploading.  shp2dta and mif2dta are the two packages that allow Stata to work with shapefiles and MapInfo files, respectively.  Spmap by Maurizio Pisati is the package that will allow you to produce basic map outputs.

(For Purchase) Tools for Matlab (http://www.mathworks.com/products/mapping/description2.html)