On all charts is indicated the number of degrees to the east or the west this magnetic meridian is, relative to the true north meridian of the chart's Mercator projection or plan of drawing.
Kwiitshati zonke kubonakalisiwe ukuba amanani amaqondo kwimpuma okanye kwintshona yeMerdiyani kamazibuthe ihlobana nomntha Meridiyani yetshati yoboniso lweMekhatha okanye ukuzotywa kocwangciso.