Re: Unique identifiers & barcodes
Subject: Re: Unique identifiers & barcodes
Date: Thu, 22 Jul 1999 16:36:52 +1000
From: "Robert K. Colwell" <colwell@uconnvm.uconn.edu>
To: "James S. Ashe" <ashe@falcon.cc.ukans.edu>,
"John Pickering" <pick@pick.uga.edu>
cc: <sackley@compuserve.com>, "Steve Ashe" <ksem@kuhub.cc.ukans.edu>,
<brianb@mizar.usc.edu>, <Gladys_Cotter@usgs.gov>,
<christine.deal@intermec.com>, <faulzeitler@ascoll.org>,
<mark_fornwall@usgs.gov>, "David Furth" <Furth.David@NMNH.SI.EDU>,
"Winnie Hallwachs" <whallwac@sas.upenn.edu>,
"Dan Janzen" <djanzen@sas.upenn.edu>,
"Norman F. Johnson" <Johnson.2@osu.edu>, <mkaspari@ou.edu>,
"Jack Longino" <longinoj@elwha.evergreen.edu>,
"Scott Miller" <scottm@bishop.bishop.hawaii.org>,
<becky_nichols@nps.gov>, <Chuck_Parker@nps.gov>,
<msharkey@byron.ca.uky.edu>, <ctemple@intermec.com>,
<cthompso@sel.barc.usda.gov>, <jugalde@inbio.ac.cr>,
"Piotr Naskrecki" <pin93001@uconnvm.uconn.edu>,
<windsord@tivoli.si.edu>, <dl@pick.uga.edu>
Steve,
Thanks for the thoughtful and helpful contribution to the discussion.
Just a couple of things about Code 49 and related matters...
>As I mentioned in an earlier communication, we experimented a lot
>with various codes before compromising on code 128 - including
>considerable experimentation with code 49. After these experiments, I
>am very unenthusiastic about code 49 - we found that its limitations as
>a data entry tool far outweighed its value as a tool for maintaining the
>maximum amount of information.
Of course, that depends on how you much you value each of those two
things.
>Because it is triple stacked, one must
>be able to scan all three lines of code before one can get an accurate
>reading. This means that the position of the barcode is limited to a
>position on the specimen from which a very large portion of the label
>can be "seen" by the scanner. This is why most people who use code 49
>place them upside down as the bottom label on the specimen. This
>increases the handling time, and we found it to be awkward.
I could not agree more--in MY inexperienced hands. But it does not take
long for "virtuoso" performance levels to develop that (e.g. for our ALAS
parataxonomists) allow remarkably rapid, 100% first-try scans. And
ergonomically, if reads are planned for points in the protocol when
specimens need to be "pulled" and re-placed in the pinning trays anyway,
the time cost of that part the process is built in anyhow.
We also use (adhesive) Code 49 barcodes on microscope slides for mites,
in Project ALAS. In this case, there is certainly no advantage to
single-row codes, since the the slide could not be read in a slide box in
any case.
> In
>addition, triple-stacked codes take longer to read, and may produce more
>errors.
Once under the reader, they do not take any longer in experienced hands
than single-row codes. As for errors, I think I can say that we have
experience absolutely NO reading errors with Code 49. If the reader beeps
its confirmation, the code is always correctly read.
But your comment made me wonder how accurately one can read the facing-up
barcode of an INDIVIDUAL pinned specimen, in situ in a tightly packed
drawer or unit tray. How can one be sure the correct specimen was "seen"
by the reader? If you have to take it out and scan it to make sure, then
nothing is saved over Code 49. But I have no experience with scanning in
situ in drawers/unit trays...so you comments would be helpful.
>Probably the only way to achieve John's goal of being able to
>instantly read all the barcodes in a tray of specmens from numerous
>museums is to force everyone to use exactly the same barcode symbology.
>If not, the reader will need to be recalibrated for each different
>code.
I believe you are mistaken. At least with the Intermec barcode readers we
use (and I suspect they are representative of high-quality ones by other
makers), the same reader can read any "mixed" serious of codes that it
has been enabled (programmed) to read. If enabled for Codes 39, 128, and
49, for example, it can read any mixture of labels with those codes, one
after another.
ALAS is not wedded to Code 49, except (as you are to 128) by prior
investment, but I want to be sure that it is accurately represented.
Best,
Rob
_________
Robert K. Colwell, Dept. of Ecology & Evolutionary Biology, U-43
University of Connecticut, Storrs, CT 06269-3042, USA
Voice: 860-486-4395 Fax 860-486-6364
colwell@uconn.edu
Visit the Biota Website at http://viceroy.eeb.uconn.edu/biota
& the EstimateS Website at http://viceroy.eeb.uconn.edu/estimates.
| Discover Life in America | Science | Unique Identifiers & Barcodes | Correspondence | Robert Colwell - 22 July, 1999 |