bernardz@... wrote:
> Jack Linthicum wrote:
> > Jack Linthicum wrote:
> > > bernardz wrote:
>
> And three degrees is 300 kilometers. When you box a compass your
> compass points are 16 Compass Pointers i.e. N,E,S,W; NE,SE,SW,NW;
> NE,ENE, ESE, SSE, SSW, WSW, WNW, NNW etc.
>
> That is 22.5 degrees. say +/- 11.2 degrees.
>
> If you double the number of points that is say +/- 5 degrees say 500
> kilometers. Enough to miss an Island completely.
Compass points have nothing to do with latitude. To measure latitude
you
measure elevation angles of stars and planets, Polar star in the
simplest
case. Anybody can measure that with their eyes and hands with 3 degree
accuracy. Add simplest tool, known at least in 1000 BC (a stick
with several perpendicular sticks), and you can measure Polar star
elevation
with 1 degree accuracy. That's max 2 degrees (220 km) latitude error
(Taking into account the fact that Polar star is not exactly over the
Pole).
If you know just a little bit more astronomy, you can probably measure
latitude with the same instrument with half degree accuracy, that's 55
km
distance.
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