magnetic deviation

Try this site here.

I think you may have your teminology mixed up .......

Deviation is the error in reading a bearing from the compass caused by the magnetic influence of some nearby object.

Variation/Declination in Perth is approximately 1.5 degrees West, so True North is approximately 1.5 degrees east of your compass reading.

Looking at my map of Port Hedland , variation is 1.9 degrees east , therefore , magnetic is least .

Peter,

the magnetic declination used 'in the field' is usually specific to that of the map or grid (in the case of surveying). assuming your trying to use the compass in conjunction with a particular map.

declination for that purpose is the difference between Magnetic North and Grid north.

all maps should state their declination (usually near north point or in title box)

a typical calm map in the south west of W.A. (DOLA -CALM would have a declination of 3-4 degrees. the NATMAP maps are closer to 2.5 degrees.

When converting a map bearing to a compass bearing, west is best (add declination), and east is least (subtract declination).

hope this helps
roopaw@westnet.com.au

Varies according to where you are as well, not everywhere in WA will be the same.

The largest declination I have experienced (not in WA) is 87 deg!

Hi and thanks for all input , I have a new digital compass to be used in WA the instructions list the Eastern states as an average of 10.8 deg East , as I will only be using it in and around southern WA I was looking for an average declination to enter in the compass
Peter