Generic Mapping Tools (GMT) is a widely used set of scientific programs for data analysis and visualization with an extraordinary broad user base within the scientific community. The broader impacts of this software are extraordinary. GMT remains a foundation in the marine and solid Earth sciences, and other infrastructure software depends on it. Over many years the PIs have made both evolutionary and revolutionary changes to the GMT code base, resulting in 13 releases of the GMT 4 series between 2005 and February 2010 and a radically new and modularized GMT 5 platform. This award includes funding to stabilize, maintain, improve and extend GMT 5, including interoperability with Geographic Information Systems (GIS), interoperability with Google Earth and other improvements.