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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