Why we use Mercator sailing Instead of Plane Sailing ?

 * Mercator sailing is another method of Rhumb line sailing .

* It is used to find the course and distance between two position that are in different latitude from the large d'lat and distance.

* It is similar to plane sailing except that plane sailing is used for small distance.

* In mercator sailing the d'lat is expressed in longitudinal units, which is the difference of meridianal parts.

* In plane sailing the d'long is expressed in latitude units or Nautical miles.