Calculate cardinal points from GPS?

[Håkon]

Tomas Gustavsson wrote:
> Hello!
>
> I was thinking if was possible to calulate the cardinal points (N,E,S,W)
> by the difference (in longitude and latitude) between your current
> location and a fixed one. By doing so we should have our compass, at
> least in my mind ;).
>
> So what do you think guys? Is this even possible?
> [...]

The GPS knows where north is. The thing it doesn't know is in which
direction the device is pointig.

When you are moving, you can calculate which direction you are moving in, so
if you point the device in that direction, it could know which way north
is.

What you also could do (maybe I misunderstood, and this is what you were
thinking about?), is to set a fixed point at the top of a mountain or
something else that vill be visible during your whole trip, so that if you
point your device at that point, you would know which way north is.

Or you could point the device at the direction of the sun, calculate its
position based on the time of day and you location, and find north.

Or you could just use a compass in addition to the gps. ;)

Oh, and sorry about not having an "In-Reply-To"-header (messing up the thread).
I don't have the original message, I have just read it online, so I
don't know how to create the header.