Open source geospatial software—spatial data management, GIS, and related developer tools and end-user applications delivered with an open source license—has co-existed with proprietary geospatial software for decades. Software developers and users often mix and match the two. The Open Source Initiative developed the definition of open source license, which consists of ten criteria. Two of these criteria are that:
Unlike proprietary software, which is written by a development team from a single software company, open source software is written by a community of developers from all over the world, some doing this as part of their paid jobs and some as volunteers. Their contributions and bug lists are managed by a steering committee. Local groups can immediately make changes to the code, but it may take a while for those changes to be accepted by the steering committee and placed into the current version. Like proprietary software, open source software is commercial in that companies can profit from it by offering services (such as installation, customization, or training) or related software.
I discussed the interplay between open source and proprietary geospatial software with: