Marvel introduces some of the amazing open source Spatial Data Infrastructure available. There is much more to an SDI than just a standalone desktop or web GIS application.
SDI is a framework of geographic data, technologies, metadata, institutional arrangements and standards that facilitate the creation, exchange and use of geospatial data across an information-sharing community. This community can be at an organization level, national level or global level.
In all cases, SDI facilitates a standardized, automated means of evaluating and exchanging crucial geospatial information and other related resources.