Open source has come a long way from its UNIX beginnings and the early Netscape browser days, persistently poking and prodding its way into technology and even societal models. Open source is an enabler, morphing the development environment’s persona. But what is open source, and how is it impacting the direction of GIS?

Open source is like an unspoken doctrine, a philosophy that supports pushing the envelope of imaginers’ minds toward freedoms of creativity and usage by removing the cost limitations. Generally, if a programmer creates an open source application, the application and its code is free of charge to the public. This code is not only available for use; it is also allowed to be copied, redistributed and modified for other purposes and intentions, as long as it remains “open” or freely accessible to the public.

Open source touches more than just software applications. Operating systems such as Linux, web browsers such as Mozilla Firefox, programming tools such as PHP and Python, web publishing platforms such as WordPress and the popular PostgreSQL Database, and many more are part of the open source family.

There are expansive definitions of open source on the web; a good place to start is on the Open Source Initiative website. To really get a feel for the difference with licensing and use between open source and that of a closed or proprietary company, try comparing OSI to Esri’s License Agreement.

GIS is being reshaped by organizations such as the nonprofit Open Source Geospatial Foundation. OSGeo’s mission is to support the collaborative development of open source geospatial software, and promote its widespread use—and there are many options to be used.

In terms of a desktop GIS option, there is Quantum GIS (QGIS). Quantum also offers a server, browser, and a web front end. Speaking of web front ends, OpenLayers allows you to use JavaScript (API) Application Programming Interface to place maps into your websites in a similar manner to Google Maps. Key components of any GIS contain imagery and terrain data, OSSIM (Open Source Software Image Map) has a powerful suite of tools that process remote sensing, photogrammetric and other map and vector data. Adding to the arsenal of tools available is GDAL (Geospatial Data Abstraction Library), which allows reading and writing of raster data. For those using Oracle Spatial, PostGIS can be substituted since it is a spatial database extender for PostgreSQL database and adds support for geographic objects. In other words, it allows location queries to be run in SQL! These are just a few of the many software and tools available for free.

However, here is where open source hits a roadblock, at least among the more traditional GIS crowd. To avoid equating free to a cheaply made product, a mental shift in thinking is required—one that is not easily made. Another concern facing open source implementation is the requirement to reveal the source code. This requirement tends to deter private for-profit companies from creating software products based on open source; they might think they will be giving an edge to their competitors by revealing the source code.

An added apprehension is that of the propriety software already installed. What are the costs of switching and retraining? What if there is a problem with the application—where and who will be tech support?

I have been and still am an avid user of Microsoft, Esri, and Oracle products, and for the most part they have been reliable solutions for the implementations I have done and overseen over my career. But open source options are also becoming valuable tools in the hands of GIS users.

Whether “open” or “closed,” both sides seem to be striving toward pushing the limits of visualizing and interpreting the geographic complexities of this world—and that will be the greatest benefit. Whether through mixing and matching GIS stacks, using solely open source or relying on proprietary solutions, GIS is here to stay and has carved its notch into technological history.