## Degrees, Minutes, and Seconds – Decimalise Example

Conversions If you are calculating the time you will arrive at your destination, you would use the Speed, Distance, Time formula. To enable the use of a calculator we must convert the minutes (or seconds as per the example) to a decimal. Once calculated, the navigator would not say, “We will arrive in 3.5 hours, …

## The Great Circle

The Great Circle is the largest circle that can be drawn around the Earth’s sphere. When cutting a sphere exactly in half you have cut along one of its great circles. All Meridians are great circles. The Equator is a great circle (i.e. cutting the Earth in half). Great circles are useful in planning routes …

## How are Longitude Angles Measured?

The green shaded area depicts the angle measured from the centre of the Earth to the Prime Meridian to the longitude line west (in this example, measured at 080°W) B is the centre of the Earth C is the Prime Meridian A is the 080°W line of longitude The orange shaded area depicts the angle …

## Where on Earth are we?

More importantly, what does that mean? Navigation is basically the art of determining where you are and what direction and distance you must go. Therefore, we must learn to find out where we are and what that means for us. We do this by understanding the nautical chart, plotting our position, and laying off direction …