## Rhumb Lines

We are now aware of great circles, which are circles drawn on the surface of earth with their centre and radius same as that of earth. Equator and Meridians are perfect examples of a great circle. Both would cut the earth into two equal halves. Their difference lies in the fact that equatorial plane is perpendicular to the axis of rotation of earth. Whereas, the plane of any meridian is parallel to the axis of rotation of earth. If we draw circles on the earth with their planes parallel to…

Great Circles In this lesson we will be discussing about Great Circles, their properties and importance. Great circles are circles drawn on the surface of earth with their centre & radius same as that of the earth. Equator is an example of a great circle with the centre and radius same as that of the earth. One of the important properties of a great circle is that, the plane of the great circle divides earth into two equal halves. Also, only one great circle can be drawn between any two…

## Measurement of Directions

Basic Directions Let us talk about the basic directions on the surface of earth. In order to define directions, we need a datum or reference point. The easiest and most obvious one is the direction of sunrise. The sun does not rise, but appears to rise in the east due to the earthâ€™s rotation about its axis. Therefore, we can define Easterly direction as the direction into which earth rotates. In the similar manner, Westerly direction is the direction from which earth rotates. If we look east, with arms wide…