The map is a portolan chart, as shown by the four compass roses (two large and two small) from which lines of bearing radiate. Some analyses assert that the map is an azimuthal equidistant projection centered on Cairo, but a 1998 analysis by Steven Dutch of the University of Wisconsin Green Bay shows a better fit with a point near the intersection of the present-day prime meridian and the equator. There are extensive notes in Ottoman Turkish around the edges of the map, as well as some interior detail which is mostly inaccurate and fanciful.