[Taxacom] Data quality of aggregated datasets

Richard Pyle deepreef at bishopmuseum.org
Tue May 7 15:57:33 CDT 2013


Hi Dave,

My use of "+/-" was in reference to the accuracy of the GPS device.  I'm not
sure how such devices estimate the error radius, and I'm not sure how the
average field biologist would find out.  However, many GPS devices I've used
give me a simple number representing "Accuracy", expressed as a distance
(usually in feet or meters).  That's a number I can easily capture as a
radius.  How the GPS device generated that number, and what the basis of the
error estimate used by the GPS device is, may be a bit more cryptic.

Aloha,
Rich


> -----Original Message-----
> From: Dave Vieglais [mailto:dave.vieglais at gmail.com] On Behalf Of Dave
> Vieglais
> Sent: Tuesday, May 07, 2013 9:05 AM
> To: Richard Pyle
> Cc: TAXACOM
> Subject: Re: [Taxacom] Data quality of aggregated datasets
> 
> In addition, the confidence associated with the error estimate should also
be
> recorded. For example, does "+/- 100m" refer to the 95% confidence
> interval? Circular Error Probable (50%)? 3 sigma ellipse (98.9%)? etc.
> 
> On 2013.05.07, at 13:20-0400, Richard Pyle <deepreef at bishopmuseum.org>
> wrote:
> 
> >> There is nothing wrong with collecting fine scale records on a GPS
> >> using
> > longitudes and latitudes, but when you are using a GPS there
> >> is no need for a radius as the error is well within the walking
> >> distance
> > of most creatures.
> >
> > You should *always* capture the radius -- even for GPS coordinates.
> > You cannot know in advance what the information will be useful for,
> > and not all GPS devices record with the same accuracy.  A GPS with +/-
> > 100m may be no different from one with +/- 10m if you are doing
> > ecological analysis; but it could make a huge difference if your goal
> > is to return to the same tree or coral head or whatever.  I think it's
> > just silly to throw away information when it's easy to capture.  It's
> > also silly to think you know in advance what information will, or will
not, be
> useful to future researchers.
> >
> > Aloha,
> > Rich
> >
> >
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