Charts are compiled from information usually obtained by hydrographic ships carrying an expert team working on sounding, sampling and surveying in a specific area.
litshati ziqokelelewe kulwazi olufunyanwa kwingcali zokubalwa kweetshati elwandle eziphethe iqela elisebenza ngokuzimisela kwizandi, kuvavanyo nasekubalweni indawo ethile.