[R] NADA Data Frame Format: Wide or Long?

Jean V Adams
2012-07-05T17:27:40Z

Rich,

I am not familiar with the NADA package, but the reference manual (
http://cran.r-project.org/web/packages/NADA/NADA.pdf) has many examples
using several data sets included in the package.  Look up one of the
functions that you plan to use, run the example in R, and look at the data
that is used in the example to see how it is organized.

Jean

Rich Shepard <rshepard@appl-ecosys.com> wrote on 07/03/2012 11:57:30 AM:

>    I have water chemistry data with censored values (i.e., those less
than
> reporting levels) in a data frame with a narrow (i.e., database table)
> format. The structure is:
>
>   $ site    : Factor w/ 64 levels
"D-1","D-2","D-3",..: 1 1 1 1 1 1 1 1
...
>   $ sampdate: Date, format: "2007-12-12" "2007-12-12"
...
>   $ preeq0  : logi  TRUE TRUE TRUE TRUE TRUE TRUE ...
>   $ param   : Factor w/ 37 levels
"Ag","Al","Alk_tot",..: 1 2 8 17 3 4 9
...
>   $ quant   : num  0.005 0.106 1 231 231 0.011 0.001 0.002 0.001 100 ...
>   $ ceneq1  : logi  TRUE FALSE TRUE FALSE FALSE FALSE ...
>   $ floor   : num  0 0.106 0 231 231 0.011 0 0 0 100 ...
>   $ ceiling : num  0.005 0.106 1 231 231 0.011 0.001 0.002 0.001 100 ...
>
>    The logical 'preeq0' separates sampdate into two groups;
'ceneq1'
> indicates censored/uncensored values; 'floor' and 'ceiling'
are the
minima
> and maxima for censored values.
>
>    The NADA package methods will be used, but I have not found
information on
> whether this format or the wide (i.e., spreadsheet) format should be
used.
> The NADA.pdf document doesn't tell me; at least, I haven't found
the
answer
> there. I can apply reshape2 to melt and re-cast the data in wide format
if
> that's what is appropriate. Please provide a pointer to documents I can
read
> for an answer to this and related questions.
>
> Rich

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