Fig. 2
From: Experiments using Semantic Web technologies to connect IUGONET, ESPAS and GFZ ISDC data portals
Main classes and elements of the extended ISDC DIF data model. The cyan colored elements are taken from NASA’s DIF standard; the yellow and green colored one are ISDC extensions to this standard. The figure is taken from Sabine Pfeiffer’s Master of Engineering Thesis (Pfeiffer 2010)