It makes enquiries and consults appropriate authorities to establish, with as much authority as possible, the most suitable name, form, and spelling for all places shown.
Mae'n gwneud ymholiadau ac yn ymgynghori ag awdurdodau priodol i sefydlu, gyda chymaint o awdurdod â phosibl, yr enw, y ffurf a'r sillafiad mwyaf addas ar gyfer pob man a ddangosir.