Hybrid GIS: combining commercial/proprietary GIS with open source GIS

We have developed a set of conceptual models that demonstrate how organizations can integrate commercial-off-the-shelf (COTSGIS) GIS software (such as ESRI's ArcView) with free and open source GIS software (FOSGIS) to increase desktop GIS functionality while decreasing GIS software costs.
Consider the cost savings involved when replacing ESRI's Spatial Analyst with a free and open source GIS application:

The video presentation below provides a comprehensive overview of how these models work, and the cost savings resulting from their use.

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