Fig. 4From: Spatiotemporal analysis of tropical disease research combining Europe PMC and affiliation mapping web servicesMapAffil coverage. Coverage of MapAffil over time, showing the fraction of papers for which affiliation information is available (top) and the fraction of these with MapAffil geocodes (bottom). This poses a challenge, especially for narrow historical analyses going back further than 1990, and explains why much published bibliometrics work begin between 1990 and 1995Back to article page