As well as describing his own projection of a hemisphere onto a plane, al-Biruni showed that by the age of 22 he was already extremely well read for he had studied a wide selection of map projections invented by others and he discusses them in the treatise.
Pati na rin ang naglalarawan ng kanyang sariling projection ng isang hating-globo papunta sa isang eroplano, al-Biruni ay nagpakita na ng edad na 22 siya ay labis na maayos basahin para sa niya-aral ng isang malawak na pagpipilian ng mga map projections imbento ng iba at siya discusses ang mga ito sa treatise .