I don't mean to possibly "sound" rude but some clarification is obviously needed:

"Variation": The difference between True North and Magnetic North.

Usually expressed in degrees & minutes, and labeled East or West; to be added or subtracted from the True North direction, as mapped/charted. Usually found within the Compass Rose and along the mapped Variation lines. There are annual additions or subtractions that must be made between the chart edition year and the year that you are using the map/chart. Use the following guides for converting to/from True North to Magnetic North:

Timid Virgins Make Dull Companions At Weddings
(true) (variation)(magnetic) (deviation) (compass) (add west)
000T + 2w = 002 - 2e = 000M

Can Dead Men Vote Twice And Eat
(compass)(deviation) (magnetic) (variation) (true)(add East)
000M + 2e = 002M - 2w = 002T

Deviation: Is the measured magnetic (usually steel construction) influence of an object (such as a ship) upon the magnetic flow around it. Ships are required to "swing compass" after shipyard work, gunfire, welding/cutting ops, and annually. Taking Deviation into effect on a vessel is necessary, but not for a hiker/backpacker trying to navigate. In the rhymes above, the hiker/backpacker would skip the deviation/magnetic parts to make the following:

Timid Virgins Make At Weddings

Can Vote Twice And Eat


Declination is a factor used in Celestial Navigation of all types. It is not a factor in terrestrial navigation using only a magnetic compass and map/chart.

Lagniappe Item: The difference between a chart and a map:
Maps are made to look at!
Charts are made to be worked upon!