nautical issues :: testing tasks - correcting for magnetic variation
Marine Navigation
Testing tasks: Correcting for magnetic variation

Example 1

An information to read out on the navigational map. To calculate correcting for magnetic variation for 2004

DEKLINACJA -0,5° W (1995)
Rocznie algebraicznie +0.1°

Solution:

2004 - 1995 = 9 year, Magnetic variation after 9 years:

d = (-0,5°) + 9 × (+0,1°) = + 0,4° E

 

Example 2

An information to read out on the navigational map. To calculate correcting for magnetic variation for 2004

Magnetic Variation
2°40 E 2000 (4' E)

Solution:

It passed 4 years from 2000: 4 × 4' = 16' which we are adding to: 2° 40', so:

d = 2° 40' E + 16' = 2° 56' E

 

Example 3

An information to read out on the navigational map. To calculate correcting for magnetic variation for 2004

Variation 0°40' E (1990)
increasing about 5' annualy

Solution:

2004 - 1990 = 14,
14 × 5' = 70' which we are adding to 0° 40' E; Magnetic variation after 14 years

d = 0° 40' E + 70' = 1° 50' E

 

Example 4

An information to read out on the navigational map. To calculate correcting for magnetic variation for 2004

Variation 1°00' W (1994)
decreasing about 20' annualy

Solution:

Magnetic variation after 10 years:

d = 1° 00' W – 10 × 20' = 2° 20' E

 

Example 5

An information to read out on the navigational map. To calculate correcting for magnetic variation for 2004

Variation 1° E (-10')
The Magnetic Curves are for 1980

Solution:

2004 - 1980 = 24 lata
24 × (-10') = (- 240')
(- 240') = (- 4°)
(- 4°) = 4° W
Magnetic variation for the year 2004: d = 1° E + 4° W = 3° W


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