Forest list archive: msg00068

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Re: Vegetation field data & handheld computers



     In response questions and comments about field computers from:
        Warren Kovach  <WarrenK@kovcomp.demon.co.uk and
        Marti Rijken   mrijken@inter.NL.net

     We have used a small field computer to a limited degree and are
     thinking about expanding its use.  Our unit is a "Husky Hunter"
     available in forestry supply catalogs.  It is a PC compatible unit
     with an 8088 chip.  It is not fast, but doesn't have to be for data
     entry.  I would not try to do any analysis or even try to run a word
     processor on it, but for field data entry, it is great.  I do not
     endorse any particular brand of field computer, but do feel that their
     use has great potential. My main complaint is the small screen.

     >  - The research makes long walks off the road necessary. The
     >  equipment must be as light as possible. Nothing can beat a paper
     >  form.

        The Husky Hunter is very small and lightweight; it hardly weighs
     more that a field clipboard.  This little computer can be easily
     carried anywhere in the field.  According to the owners manual, it can
     be completely submerged and still function (we have not tried this).
     You cannot say the same for paper, even write-in-the-rain paper.

     >  - The screen is not large enough to hold a full A4-size form with
     >  preprinted species names. So typing names will be necessary. In
     >  many cases not the whole species list will fit on one screen. This
     >  makes it more difficult to keep a track of the complete species
     >  list.

        I agree in full that the small screen on field computers is a
     serious drawback.  It would be much preferable to have more of a "data
     sheet" visible on the screen.  Typing in species names, however, is
     not really a problem.  We use 4 digit acronyms for species names (TADI
     for Taxodium distichum, for example).  Rather than looking up and down
     a list of species names you could have your program such that you
     enter the species and it would append the information to the master
     list internally.  A good program would also have a "hot key" to allow
     scanning of the list or examination of the data.  I like programs like
     the old dBase III+ for data entry on a field computer, or you could
     write your own in just about any programming language.

     >  - With data entry in the field you have nothing to fall back onto,
     >  if later you find unprobabilities in the data.

        This has always been one of my concerns, but if the data entry
     program is configured correctly you can have it check for errors as
     you enter data.  If you enter a 4 digit acronym that is not recognized
     or if you enter 100 when the possible values must be less than 10
     etc., the computer could let you know that something is wrong.  In
     falling back on paper data sheets I have often found obvious errors on
     the data sheet and had "nothing to fall back onto."  Every time you
     handle the data, recording the data in the field or entering the data
     in the lab, you have the potential for introducing errors.  By
     reducing the number of times the data is handled, you may reduce the
     possibility of errors.

     >  - In our climate we can count on some days with bad weather :-)
     >  We can use these days to do data entry at home or at the office,
     >  with more accuracy than in the field.

        Yes, bad weather is a bear and it often keeps us in from the field.
     If your data had been entered in the field you could spend bad weather
     days analyzing data or writing or reading journal articles or . . .
     rather than entering data.  Plus, with a weather resistant field
     computer, you can keep entering data in the field if bad weather
     develops.  Even with write-in-the-rain paper I have had to give up and
     go back to the lab during rainstorms because the paper becomes mush if
     it gets too wet (although it does work quite well in light rain).
     Sometimes, if you just have a little work to finish a plot or you are
     collecting time-series data that MUST be collected at a specific time,
     it is necessary to collect data in bad weather and a weather tight
     field computer is great.

     >  I must emphasize this point.
     >  It is important to let the researchers do their own data entry to
     >  prevent errors. I've tried to let typist do it, with really bad
     >  results, even with an error checking program.

        I totally agree.  The best scenario is for the researcher to record
     the data directly into a computer in the field.

        My main concern was that the batteries would go dead in the middle
     of a field trip and all of the days data would be lost.  The little
     computer we have has a lithium backup battery that maintains data
     storage while you change the main batteries.

     BobK




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# Bob Keeland, Ph.D.                 FOREST ECOLOGIST         #
# NBS, Southern Science Center       PHONE: (318) 266-8663    #
# 700 CajunDome Blvd.                  FAX: (318) 266-8592    #
# Lafayette, LA  70506            INTERNET: keelandb@nwrc.gov #
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