Where in the World am I?

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Latitude and Longitude Explained


We are at 17° 04′ North and 061° 53′ West.
Where are you?

Latitude & Longitude are reference grids used to identify specific points on Earth – they are used so we can see exactly where we are on a map or chart.

Grid Lines

The grid lines that go around the world are Latitude lines, or ‘Parallels’, and are based on the Equator, and the references are counted in degrees (°) North of the Equator and degrees (°) South of the Equator. The Equator is at 0° and the North Pole is at 90° North with the South Pole at 90° South.

Longitude is measured East and West from a grid line that starts at the North Pole and goes directly through London, UK – ending at the South Pole – this is known as the ‘Prime Meridian’ and is 0°.

Latitude lines are very useful to the navigator because they give us a way of measuring distance as well as locating our position. The grid lines are parallel, and therefore equally spaced out around the World. They are measured in degrees (°) and minutes (‘) – 1° is 60′ – 1’ is referred to also as One Nautical Mile (nm).

A Nautical mile is slightly more than 15% longer than a ‘land’ mile. It is 1852 meters long (a land mile is only 1609m). These nautical miles are divided into Tenths known as ‘Cables’ (185m)

The Latitude scale is on the left & right hand sides of a chart or map, and gives a simple measure for distance.

Longitude gives us a way of measuring time – the lines of Longitude, otherwise known as ‘Meridians’ are used to divide the world in to time zones – based on the time in Greenwich, London. The time at Greenwich used to be known as ‘Greenwich Mean Time’ (GMT) – it is now referred to as Universal Time (UT). The Earth revolves through 15° every hour – there are 24 hours in the day, and the earth revolves through 360° in these 24 hours. This is why the World has been allocated 24 Time Zones – taken to the West 12 hours & to the East 12 hours and meeting at the International Date Line near Australia & New Zealand (Approximately 180° East or West of Greenwich)

Time Zones

Pippa Turton
Chief instructor
Miramar Sailing School

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