I'll give you another one too - for some reason the Earths Magnetic poles will flip over - South becomes North and North becomes South - but fortunately this is highly unlikely to affect us in our life timeTo compound matters, the earth's magnetic field doesn't run straight north-south, either. In some parts of the world the deviance can be 30 degrees! Any decent topographical map will tell you the magnetic deviation, the year the map was printed and the annual change in deviation
Map Reading Techniques (Tutorial)
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Add degrees or take them away....which one is it?
Hi All,
I was told an easy way to remember whether to add or subtract the deviation by a yatchy friend:
If your taking a bearing by sight to transfer to the map - take the bearing, then go down to the map (or chart ), down means less so take the deviation away. If your taking a bearing from the map to sight, up from the map so add the deviation on.
Hope this helps a little.
MJ
I was told an easy way to remember whether to add or subtract the deviation by a yatchy friend:
If your taking a bearing by sight to transfer to the map - take the bearing, then go down to the map (or chart ), down means less so take the deviation away. If your taking a bearing from the map to sight, up from the map so add the deviation on.
Hope this helps a little.
MJ