using GPS units for not getting lost in the scrub

Subject: using GPS units for not getting lost in the scrub
From: Paul Taylor <>
Date: Thu, 11 Oct 2001 12:16:13 +1000
Vicki Powys wrote:

> I'm now using a GPS unit (the most basic Magellan unit available from RAOU)
> for atlassing.  I've tried it out around home for "not getting lost" and
> I've found I really need to use a magnetic compass in conjunction with the
> GPS unit, to find direction accurately.  Is this what other people do?
> Perhaps there are more precise units than mine?

The direction shown on GPS units is really direction of travel,
and is calculated by comparing two or more consecutive coordinate
readings.  If you aren't moving, or don't move far enough to 
register a difference in coordinate readings, the direction 
indicated is more or less random.  This affects all GPS units
other than those with a magnetic compass built-in (e.g. Silva
> To find North via my GPS, I need first to take a reading, then proceed at a
> fast gallop for 20-30 metres before the corrected north arrow shows up on
> the GPS screen, and fast gallops are not possible on mountain tops, or in
> scrub.  Hence the compass.  Any other ideas?

Most GPS units let you mark waypoints, and will give you a 
bearing and distance to the waypoint from your current position.
Some will also give you the bearing and distance between two
waypoints.  If you mark your starting point then walk a reasonable
distance, say 50m, you should get a reliable bearing to the 
starting point even while standing still.

   Paul Taylor                           Veni, vidi, tici -
                    I came, I saw, I ticked.
Birding-Aus is on the Web at
To unsubscribe from this mailing list, send the message
"unsubscribe birding-aus" (no quotes, no Subject line)

<Prev in Thread] Current Thread [Next in Thread>

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the birding-aus mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU