[Taxacom] GPS units that record the time a waypoint was taken

Karl Magnacca kmagnacca at wesleyan.edu
Thu Mar 19 05:17:55 CDT 2009


On Thu, March 19, 2009 5:57 am, Peter Oboyski wrote:
>
> And what about accuracy?? Location accuracy can be very important and
> most georeferencing databases include a field for it. The information is
> presented on the screen at the time the waypoint is taken. Are there any
> units that include this information with the waypoint (along with date
> and time) in the download file?

Of course, then there is the question of how accurate "accuracy"
measurements are.  If the unit says that the accuracy is 20 m, but over
a long period at the same point (or repeatedly moving away and coming
back to it), it only fluctuates by 3 m, does that mean the accuracy is
really 3 m?  Or is it that the point might be consistently 15 m off? 
Also, WAAS is supposed to increase the accuracy, but when enabled on my
unit it inevitably decreases the accuracy shown (but again, I don't know
whether it might be actually recording more accurate data).

Karl
=====================
Karl Magnacca
Postdoctoral Researcher
Department of Zoology
Trinity College, Dublin 2
Ireland





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