Re: Unique identifiers & barcodes
Date: Wed, 21 Jul 1999 09:15:49 -0500
From: "James S. Ashe" <ashe@falcon.cc.ukans.edu>
To: John Pickering <pick@pick.uga.edu>
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Subject: Re: Unique identifiers & barcodes
Hi John and everyone,
This continuing discussion seems to indicate that we at KU are the
only ones that like code 128. I am surprised that it is so uniformly
found to be inadequate. Except for the compromise of accepting only a
2-letter acronym, we find that code 128 exceeds other codes in it's
primary function of facilitating data entry.
I agree that if you want a long list of alpha characters included in
the barcode symbology then code 128 simply cannot be made small enough.
We experimented with this considerably before deciding to include a
shortened institutional identifier (we use "SM" for "Snow Museum") in
the barcode symbology. We also include the full institutional
identifier (we use "KUNHM-ENT" for "University of Kansas Natural History
Museum - Division of Entomology") in an additional text line. The
additional text line is possible because a single stacked barcode can be
much narrower, so that one can get 3 lines of information on the label
(we have the barcode symboloby, the full alpha-numeric written out, and
the full institutional identifier written out). We recognzed that this
was a compromise. However, we believed that it was reasonable because
the single-stacked code 128 was small (our barcode labels are 7 by 15
mm) and it is extremely easy, accurate and fast to read, and allowed us
to place the barcode as the bottom label and still read it from above.
Our primary goal was to make data entry as fast and accurate as
possible, while at the same time preserving essential information. We
thought that the compromise of having a shortened institutional
identifier in the symbology, and the full identifier written out on the
label allowed one to easily determine the origin of the specimen. In
effect, we felt that the full written alpha-numeric specimen identifier
is the only truely "archival" part of the label - the barcode is
transitory technology.
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. 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. In
addition, triple-stacked codes take longer to read, and may produce more
errors. I would be reluctant to change from code 128 to code 49
symbology. Still, if one can identify a barcode symbology that combines
the advantages of code 128 with the greater information content of code
49, I would be glad to change our system.
We have considerable commitment to code 128 - a database of over
180,000 specimens that have code 128 barcodes on them, and an investment
in about 100,000 additional code 128 labels. It has served our needs
well. Nonetheless, I have no enthusiasm for being the only collection
using code 128, if it fails to meet community needs for institutional
identifier. While I don't think that the specific symboloby used is
critical, the issue of consistency in institutional identifiers is an
important one. If we need to change to another barcode symboloby to
satisfy those needs, then we will. But I strongly urge the community
NOT to make the issue of barcode standards so stringent and restrictive
that they serve as an disincentive for development of accurate and
informative specimen databases, These are our real goals - barcodes
should only be a facilitate that end. I am increasingly concerned that
the debate about barcode standards will discourage and delay, rather
than energize people toward, development of specimen databases.
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. Still, I'm not sure that we can ever expect to impose absolute
standards for barcode symbology on the community - and to have that be a
truely effective solution. Who is going to police the standards, and
how will they enforce them? In addition, such a rigid standard
discourages innovation, prevents incorporation of new technology, traps
the community in a standard that will become archaic (note that this
discussion began because of the possibility that code 49 was already in
danger of becoming outdataed) and discourages people from developing
databases who find it difficult to meet that standard.
The cost of barcoding specimens that John mentioned is probably not
avoidable. Good barcode scanners are essential for efficient and
error-free reading - inexpensive ones don't work well enough with the
small labels required for insect specimens. We have saved in the long
term by purchasing a bar-code printer (with the Division of Botany), and
we make our own. We expect a long-term need for barcodes, and the
potential use of hundreds of thousands, so such an investment pays off
in the long run. However, I would not recommend this solution for all
users. The initial cost for printer, barcode formating software,
scanner, label stock and printer ribbons was well over $5000 (this is
probably cheaper today than 4 years ago), not to mention the
considerable investment in time for learning to use the difficult (to us
anyway!) programs required to make customized barcodes. In addition,
both label stock and printer ribbons are a significant continuing cost.
I agree that the entomological community is not likely to be a large
enough market to significantly force the price down. At least on the
surface, there seems to be relatively little economy of scale to be
gained because each institution requires that the barcodes be
"customized" with their institutional identifier.
It is important for everyone to remember however, that the cost of
barcodes should not be an excuse for failing to database entomological
specimens. It is easy to forget in this discussion that the barcode is
only an identifier for a specimen. Its' sole purpose is to increase the
efficiency, speed and accuracy of entry of that identifier into a
database. The cost can be avoided by simply labeling specimens with a
alpha-numeric label that identifies the specimen. One looses the
data-entry advantages of barcodes, but the goal of a unique identifier
for each specimen is fully achieved by the "low-tech" alpha-numeric
printed label. Most vertebrate collections do not use barcodes because
they handle so few specimens (relative to insect collections) that the
simple alpha-numeric identifier on the specimen label is adequate for
databasing standards - and many of these vertebrate collections have
fully functioning databases of their collections that do not suffer in
the slightest from the fact that their collection is not barcoded. On
the other hand, coding the specimen identifier into a barcode improves
the handling rate (and accuracy) by several seconds per specimen. These
seconds add up into very large blocks of time when the number of
specimens that entomologists handle are taken into account.
I hope these randon thoughts are useful additions to our
discussion. My best wishes to all.
Steve Ashe
> >******************************************************
> >John T. Longino
> >Lab I, The Evergreen State College
> >Olympia WA 98505 USA
> >longinoj@evergreen.edu
> >Ants of Costa Rica on the Web at http://www.evergreen.edu/ants
> >Project ALAS at http://viceroy.eeb.uconn.edu/ALAS/ALAS.html
> >******************************************************
--
James S. Ashe
Division of Entomology
Snow Hall
KU Biodiversity Research Center/Natural History Museum
University of Kansas
Lawrence, KS 66045
U.S.A.
Phone: (785)-864-3030
Fax: (785)-864-5260
e-mail: ashe@falcon.cc.ukans.edu
| Discover Life in America | Science | Unique Identifiers & Barcodes | Correspondence | James Ashe - 21 July, 1999 |