What is difference between Mercator projection and Gnomonic projection?

MERCATOR PROJECTIONGNOMONIC PROJECTION
On a mercator projection chart, lines of latitude are parallel as are lines of longitude.On gnomonic projection charts, meridians converge and lines of latitude are curved.
A rhumb line course of 040° crosses each meridian (lines of longitude) at the same angle.Great circle routes are straight lines and rhumb lines are curved.
A rhumb line course is used in all coastal navigation. If a passage is over 600 miles it may be quicker to sail a great circle route, in practice this not always practical as winds, currents and weather systems all influence the choice of the best route.A great circle is the longest line that can be drawn around the earth. A segment of a great circle is the shortest distance between two points on the earth surface.

SUMAN KUMAR