World maps of plasma frequency foF2 obtained with IRI RTAM by assimilating data from the Global Ionospheric Radio Observatory (GIRO) into the IRI model for foF2. The left panel shows the final map. The right panel shows the GIRO digisonde stations (circles) that contributed and the color in the circle percentage difference between IRI and the GIRO measurements. The color in the rest of the right panel shows the percentage difference between RTAM and IRI.