C om putations are reckoned of the geographic and right coordinates of the points indicated ont he portolano (m aps based on the hypothesis th at the E arth is flat and th at depict the im portant features of a port) m ade in 1513. in the study conducted ont he Piri Reis m ap, the regions in proxim ity to the equator corresponded closely to alm ost every projection. C alculations for places m ore distant from the equator failed to accord \vitlı the projection systems. Extrem e Iack of congruity was evident in the regions close to A ntartica.