A rich treasure of open source tools is at hand for anyone interested in exploring the cutting edge of geospatial analysis. Tyler Mitchell, a geographer and open source geospatial advocate, surveys the breadth and depth of free software for the management, manipulation, and presentation of geographic data on the desktop or via web services. Building on open standards for interoperability, the energetic open geo community is in the vanguard of mapping technologies, making these open tools a competitive alternative to GIS packages from commercial vendors.

Many free mapping tools and projects are out there, but keeping track of which ones do what jobs takes some guidance. Mitchell first sketches current options for database storage and analysis of geographic information, which can be a more powerful option than desktop software. One prominent example is the PostGIS database (based on PostgresSQL) which provides the analytical power of a query language, and supports a broad range of data types. The Geospatial Data Abstraction Layer (GDAL, sometimes pronounced 'goodle') provides useful command line tools for the conversion of raster and vector datasets. For those interested in internet mapping through web services, Mapserver is a powerful way to build spatially-enabled internet applications to render geo data on the web.

More functions for map creation and data visualization, manipulation, analysis, and conversion can be had by combining a variety of libraries and utilities. Be sure to view Mitchell's presentation file (see Resources below) for a good summary of the available options. As these projects develop further in common with the open source mindset, we can expect that timely updates and new innovations will continue to flow.