GIS Development: August 2007:Open Source Tools for GIS Professionals

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Open Source Tools for GIS Professionals

Salvador Bayarri, Alvaro Anguix
IVER Technologies, Valencia, Spain
Salvador.Bayarri@iver.es,Alvaro.Anguix@iver.es

Open Source Software (OSS) has been maturing over the last years into robust, well-supported tools whose code base grows exponentially. Open Source GIS is no exception to this trend and it is now able to address the needs of GIS professionals worldwide.

Open Source Software can be defined as software where the authors give a number of fundamental freedoms to the users via a license agreement, including the possibility to study how the programme works, to adapt and improve the code according to specific needs, to run it for any purpose on any number of machines and to redistribute copies of the code to other users.

The main advantages of using OSS, cited by respondents in business reports are the absence of licensing fees, vendor independence, flexibility, access to source code and better interoperability through standards-based technology. The UNU-Merit Report on the impact of Open Source in the European economy, funded by the European Commission, concludes that Free and OSS-related services could reach a 32% share of all IT services and a 4% of European GDP by 2010. According to the same report, Europe is the leading region in terms of globally collaborating FLOSS (Free/Libre/OpenSource/Software) developers and projects, followed closely by North America, Asia and Latin America. European initiatives like IDABC are promote the use of OSS as the way to interoperable services in and from the public administrations, and is indeed in public administrations where OSS has had a wider diffusion.

OSS IN GEOSPATIAL APPLICATIONS
Building on existing OSS operating systems, database, web services and software development technologies, today we find well-established OSS systems focused on geospatial applications. These systems range from spatiallyenabled databases like PostGIS, data analysis environments like GRASS, web server technologies (MapServer, GeoServer, Deegree) and client-building tools (MapBuilder, MapBender) to professional desktop GIS tools like gvSIG. Due to their emphasis on interoperability, these OSS tools have strong support for OGC standards, including web geoservices.

Most OSS GIS products rely on both open communities and private companies for development, integration, technical support and training. Because of the openness of the software, small and medium-size companies can easily provide customized solutions and services. It is our experience in Europe that many SMEs which previously relied on proprietary technologies are, more and more, using and providing OSS solutions. This process feeds itself in a kind of snowball effect, in which successful projects are used as reference and as template for new ones. In addition to the generic advantages mentioned before, some reasons for OSS expansion in the European geospatial sector are:

Open Source

The increase in functionality, quality and support of the OSS GIS tools. Compared to proprietary software, the open nature of OSS makes easier to fix problems and reuse libraries and pieces of code when creating new or integrated solutions.
The wide movement towards OSS migration by public administrations in Europe. This process has been encouraged and guided by EU-sponsored initiatives as well as national policies. Many case studies are listed in the UNU-Merit Report. This migration process frequently involves OSS GIS development, as we can see in Spain and it has been adopted by administrations at all levels. In fact, the regional and local governments are typically the most proactive.
The growing emphasis on interoperability and open standards at the European level. Of special importance for the geospatial community is the adoption of the EU INSPIRE (Infrastructure for Spatial Information in Europe) Directive, which aims at the creation of a European Spatial Data Infrastructure (SDI) that delivers integrated spatial information services linked by open standards (Fig.1).

Fig. 1: An SDI architecture built on Open Source Software (taken from [13])

This kind of OSS-based SDI architecture compares well with equivalent proprietary software providing standard web services, in terms of functionality, reliability and performance. Today, server technologies like MapServer, GeoNetwork and OSS client toolkits are competing in equal terms and being adopted in a huge number of SDI implementations (estimated 30K-50K for MapServer). But that's not the whole story.

BEYOND GEOPORTALS:THE EXAMPLE OF gvSIG

For many, to use a Spatial Data Infrastructure means accessing a geoportal for searching, displaying and maybe downloading data from remote services. However, in project after project we have found that professional GIS users want to combine SDI data access with a work flow that requires a thick client, a desktop GIS application. In the future, it is likely that some analysis processes may be carried out remotely (for instance, using the emerging WPS specification) and vector data editing could be implemented more efficiently and reliably via web services, but today these tasks and others are better served by a local GIS application, especially when it can be stripped down and customized to user needs, and replicated as many times as needed without license costs. A good example of how OSS desktop GIS has advanced in recent years is the development of gvSIG; a modular, plug-in-based system which in its current release can cover most of the GIS needs for a wide variety of users.