[Taxacom] Data quality of aggregated datasets

Dave Vieglais vieglais at ku.edu
Tue May 7 18:20:36 CDT 2013


Hi Rich,
The confidence interval for the error estimate these devices provide should be available in the specifications, though that may not be the case in devices not warranted for instrumentation. Where it is available though, it is useful to record in the metadata since this is helpful for analyses, and where it's not, at least the device name and model should be noted.

cheers,
  Dave V.

On 2013.05.07, at 16:57-0400, Richard Pyle <deepreef at bishopmuseum.org> wrote:

> 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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> 
> 





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