Two compasses are not enough!

From: Simon D. Hibbs (S.Hibbs@fcrd.gov.uk)
Date: Thu 08 May 1997 - 12:49:36 EEST


Thomas Gottschall :

>Please, all who believe two compasses are not enough do this :
>
>1.Take a map of Glorantha (or a piece of paper) and mark two point A and
>B on it.
>2.Now determine what direction compass A and B point to.
>3.Draw a line through point A with the same direction as the compass
>showed.

Which way round are you holding the map, and why? If you rotate the map,
the line you draw will be different. You need another (a third) known
fixed refference so you can draw the lines A and B relative to that.
What you are doing is using the bottom edge of your arbitrarily oriented
map as a base line, without actualy knowing it's orientation relative to A
or B.

>4.Do the same with compass B.
>5.Your lines meet in one point, this is the point where the two
>compasses show your before determined directions.

Suppose that in Dara Happa they usualy hold their maps with East (the
direction of the rising sun) at the top, but that in Sartar they always
hold them with north at the top. A Sartarite and a Dara Happan, both using
the same two compasses, would end up with two totaly different results
using this method. Try it yourself.

Simon

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