Latitude and Longitude

Writing latitude and longitude correctly is extremely important. The next person on watch must be able to read and understand what you have written on the chart and in the log book.

Latitude should always be written first (in some areas in the USA longitude is written first, latitude first is more widely accepted):

E.g.                         00° 36ʹ 12ʺ S    080° 25ʹ 42ʺ W

Written above shows: degrees (°), minutes (ʹ) and seconds (ʺ).

There are sixty minutes in a degree and sixty seconds in a minute.

You can instantly spot an error if the minutes (ʹ) or seconds (ʺ) are sixty or higher. The highest number of minutes that can be used is fifty-nine: e.g. 1     00° 59ʹ 12ʺ

00° 61’ 12” is incorrect and should be: 01° 01ʹ 12ʺ

E.g. 2     001° = sixty minutes

00° 62ʹ is written incorrectly and should be written as 01° 02ʹ

Just like a clock we have 60 seconds to the minute, 60 minutes to the degree and 360 degrees to the circle. This means that we can now express angles down to a very small measure, e.g. 76°35’36”. This can also be expressed as 76°35.6′. Here, we have decimalised the seconds. This method is the most common when using angular measure. To do this we divide the number of seconds by 60.

EXAMPLE:           36 seconds   =                    36 / 60  = 0.6 minutes

6 seconds = 0.1

12 seconds = 0.2

18 seconds = 0.3

24 seconds = 0.4

30 seconds = 0.5

36 seconds = 0.6

42 seconds = 0.7

48 seconds = 0.8

54 seconds = 0.9

60 seconds = 1

Leave a Reply