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Open Source Software

This project uses “open source” software.  Software distributed under the various open source licenses are all free of charge to users.  They are typically downloaded directly from the project's website, or downloaded from any number of software repositories.  This is the “free as in free beer” aspect of open source.  This aspect provides our project participants affordable access to a variety of GIS and web mapping application software.

Another key aspect of open source is its “free as in free speech” aspect.  Source code for open source products is also available for anybody to download, modify, distribute, and use.  Typically, once a user modifies the software for his/her use (whether for personal or commercial purposes), the user is expected to make that modified code available to the open source community.  Exactly how and under what circumstances the modified code must be submitted to the community is the subject of a large variety of open source licenses which govern software usage and development.  Our project does not participate in this aspect.

One definition of open source is available from website of the Open Source Initiative.  Software thus developed are collectively known as Free and Open Source Software (FOSS).

Another unique aspect of open source software development is that most of the software is being written in a totally volunteer capacity by professional programmers and by computer-savvy specialists in other fields.  Most of these developers have day jobs, and do their open source programming in their spare time.

Dr. Ian Turton, the erstwhile instructor of Geog 585 - Open Web Mapping at Pennsylvania State University's MGIS program, explains this phenomenon thus:
You might also have a nagging doubt as to why people would write software in their spare time.  In many cases it's simply because they can.  Why else would people build models of the Golden Gate Bridge out of toothpicks?  Also, a lot of developers actually write FOSS during their work time (often with their employer's knowledge).  For example, the Geography department at Penn State produces several open source programming projects and contributes to several more.  We'll even get to play with some of them during this course (which justifies the work and makes everyone happy).
Software development by enthusiastic volunteers in their spare time has certain drawbacks, as will be discussed in more details in the Project Tutorials subsection and in the References section of this website.

A common aspect of the multitude of available open source GIS software is adherence to open standards.  In the geospatial field, the Open Geospatial Consortium (OGC) establishes standards, accepted world-wide, to allow spatial data sharing and interoperability.  Refer to this Penn State Open Web Mapping Courseware page for some of the OGC standards upon which this project's web mapping component depends.  Other OGC standards of interest to both the desktop GIS and web mapping components include Keyhole Markup Language (KML) and Geographic Markup Language (GML).

Another advantage to adopters of open source software, whether in the geospatial field or in others, is that because software is standards-compliant, and because software is free of charge, users can avoid the so-called “vendor lock-in.”   Purchasing a license from a proprietary software vendor typically forces purchasers into upgrade cycles as the vendor unilaterally decides to change (proprietary) file formats and software interfaces, rendering older software “incompatible” with these newer formats and interfaces.  Standards-compliant open source software greatly reduces the risk of current software becoming incompatible with existing open standards.  When open standards, by community consensus, evolve, software upgrades can be made at no charge to the user.  If an organization elects to purchase support services for open source software through a software service company, the organization can change support providers at will without jeopardizing software license contracts (Shorter, 2010).

There are numerous open source software products with sufficient functionality to serve as replacements for their commercial counterparts.  For example, LibreOffice and OpenOffice are open source alternatives to the Microsoft Office suite, while the open source GIMP provides an alternative to the raster manipulation capabilities of Adobe Photoshop.  The  open source vector file creation and manipulation counterpart  to GIMP is Inkscape.  Other open source alternatives to commercial software in a variety of consumer product categories can be researched at websites such as Open Source as Alternative and alternativeTo.  Go and browse these sites; you will most likely be surprised at what's available!

In the next subsection, we will discuss the open source geospatial community, our source of open source GIS software!