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EOM July 2005 > Departments > Understanding Technology
Open Source Software: Opening the GIS Market From The Foundation Up
Chris Andrews
For system integration projects, open source software (OSS) is essential. Developers compile source code with tools such as Ant and Maven from the, a pioneering organization devoted to building reliable, useful OSS development tools. Project teams on many software development efforts use a free tool called XPlanner for tracking tasks and recording time. Knowledge management, software modeling, image manipulation, and many other vertical technologies benefit from OSS developed over the last decade. Even the GIS world grew its own share of open source projects over the years, but the average GIS project has been slow to adapt open source technology. Most mainstream GIS tools relied upon proprietary database and data exchange standards until very recently. This reliance on proprietary technology contributed to a lack of interoperability that helped to slow the development of open source GIS tools.
Figure 1: Go Spatial Ltd. is experimenting with the use of UMN MapServer to advertise the company's collection of vector and raster data for sale. The image shows the Go Spatial Ltd. mapping application with some data from Madagascar. Click on image to see enlarged.
Over the past 11 years, the Open Geospatial Consortium, Inc. (OGC) pioneered the definition and use of standard data formats and data exchange tools that have provided a backdrop for the OSS movement in GIS. However, the definition of OSS remains somewhat slippery. While the OGC promotes standards, standards alone only offer the promise of interoperability, not true openness. OSS must in some way be free of cost and, to truly be considered open source, must be distributed with a license that details exactly how the software is available to the public. Numerous OSS licenses exist in the marketplace, each with its own definition of "free." Software licensed under the GNU General Public License (GPL) are free for public use and require that any derivative products remain free and open for public use. Use of software under the GPL does not usually present a problem to agencies that do not produce software for redistribution. Software licensed under the "Berkeley-style" license, called the BSD license, may be used, included, and repackaged by software products that are free or sold in the commercial marketplace. BSD-licensed products may be, and often are, included with other software in a package sold and licensed commercially. There are many other open-source-styled licenses; however, OSS developers generally offer no warranty for users of their products.
The lack of a warranty is not a good reason for avoiding OSS. Good OSS projects benefit from a diverse, often international, user community that hacks away at OSS till bugs, deployment issues, and features are smoothed out and modified according to popular consensus. Probably the oldest free GIS application is GRASS, the Geographic Resources Analysis Support System, originally developed by a branch of the U.S. Army Corps of Engineers starting in 1982. GRASS has been in continuous development since the early 1980s and now offers high-end raster and vector GIS analysis capability. GRASS can even use a relational database for a data store and has plug-ins that offer the capability of standard GIS graphical user interfaces. The University of Minnesota MapServer project, originally funded by a National Aeronautics and Space Administration (NASA) grant, developed a toolkit for building GIS-based Web applications. MapServer is not intended to be a replacement for desktop GIS, but instead supports OGC-compliant Web operations, raster and vector data, and a variety of thematic mapping and map generation tools. One of the best features of MapServer is that new users can reach the core development team for technical help and suggestions directly, using mailing lists or instant messaging.
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A strong entry into the OSS GIS space has been the PostGIS project from Refractions Research of Victoria, British Columbia. PostGIS adds the capability of storage, retrieval, and indexing of geographic information to the OSS PostgreSQL object-relational database developed by The PostgreSQL Global Development Group at the University of California. Refractions' PostGIS site has more than 1,500 downloads per month. PostGIS offers a wide variety of "expected" spatial database functionality, including simple SQL queries for accessing geometry, functions for geometric unions and other complex operations, and indexing capability. According to Paul Ramsey, president of Refractions, users have indicated that they are choosing PostGIS over proprietary databases because PostGIS is less expensive and offers all of the functionality that can be found in a proprietary off-the-shelf package. For example, GlobeXplorer, LLC, a vendor of satellite and aerial imagery, uses PostGIS to support a high-performance ordering, billing, and tracking system for their business.
There are many reasons for the slow penetration of OSS into the GIS market. Large GIS vendors initially dominated the GIS industry and these vendors not only provided GIS software, but also funded many high-visibility experiments with the use of GIS technology. GIS vendors are software sales organizations, so their business models included no incentive to use or produce OSS. Many open source development tools start off generic and become customized to fit specific vertical business models after time has been invested in the generic solutions. In the GIS world, the inertia of legacy proprietary software implementations allowed the commercial software vendors to establish close ties between their software and specific business functions before OSS could be developed to fit these functions. In the past two years, we have finally seen OSS software that solves infrastructure problems such as Web-based data sharing and data storage. These OSS solutions provide the GIS market with a foundation for open source applications that will offer more vertically functional GIS tools as the market matures. 
The author thanks Paul Ramsey of Refractions Research and Chris Becwar of GlobeXplorer, LLC for their comments and suggestions.
About the Author
Chris Andrews has been an advocate for standardizing and extending the use of GIS technology in the enterprise for the past eight years. He has programmed and listened to customers in a variety of environments, from private industry to the Kennedy Space Center. Chris is currently employed with TAG The | Asset | Group, a division of MWH Global, Inc., in Denver, Colorado, and may be contacted at [email protected].
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